Yolk Sac Tumor
Yolk sac tumor (YST; endodermal sinus tumor) is a malignant neoplasm defined by primitive extraembryonic/endodermal differentiation rather than by one anatomic site or one molecular route. It occurs as a pure tumor or as a component of a mixed germ cell tumor in gonadal, extragonadal, and central nervous system sites; morphologically similar, somatically derived YST differentiation can also arise in a non-germ-cell carcinoma. These settings are not biologically interchangeable. In particular, prepubertal-type testicular YST is generally unrelated to germ cell neoplasia in situ (GCNIS) and usually lacks 12p gain, whereas postpubertal-type testicular YST is a GCNIS-related component of type II germ cell tumor and may belong to a 12p-gained clone. Diagnosis integrates morphology, immunohistochemistry, and serum alpha-fetoprotein (AFP); staging and management remain site- and age-specific.
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Classifications
ICD-O Morphology
Subtypes
7
Prepubertal-type testicular yolk sac tumor
NCIT:C192100
Usually a pure testicular tumor in infants and young boys. It belongs to the GCNIS-unrelated/type I testicular germ cell tumor pathway and is molecularly distinct from postpubertal-type YST.
Postpubertal-type testicular yolk sac tumor
NCIT:C192099
A GCNIS-related/type II testicular germ cell tumor histology, usually encountered as one component of a mixed nonseminomatous tumor. Claims about the entire mixed tumor are not automatically assigned to its YST component.
Ovarian yolk sac tumor
MONDO:0006344
A malignant ovarian germ cell tumor affecting children, adolescents, and young adults. Pure, mixed, and AFP-defined putative YST cohorts must be distinguished when interpreting treatment and outcome data.
Pediatric extracranial extragonadal yolk sac tumor
Includes sacrococcygeal, retroperitoneal, vaginal, and other extracranial sites in children. Site modifies presentation, staging, and outcome.
Mediastinal postpubertal-type yolk sac tumor
Usually part of a primary mediastinal nonseminomatous germ cell tumor in an adolescent or adult male. This setting has distinct poor-risk management, a strong association with Klinefelter syndrome, and a specific risk of clonally related hematologic malignancy. It should not be conflated with pediatric mediastinal type I germ cell tumors or with gonadal YST, and the mediastinal-germ-cell-tumor risks are not automatically YST-component-specific.
Central nervous system yolk sac tumor
MONDO:0016739
An AFP-secreting nongerminomatous CNS germ cell tumor component. CNS tumor-marker thresholds, staging, radiation fields, and protocols are distinct from extracranial disease and are curated in the CNS germ cell tumor entry.
Somatically derived yolk sac tumor differentiation
YST morphology and immunophenotype arising in association with a non-germ-cell malignancy. The probable histogenesis is lineage plasticity of a malignant somatic precursor rather than a conventional germ cell tumor.
Discussions and Knowledge Gaps
4Which precursor cells and developmental trajectories generate prepubertal-type, postpubertal GCNIS-related, ovarian, extragonadal, CNS, and somatically derived YST, and which molecular events are shared versus context-specific?
Attached to
Morphologic convergence on primitive endoderm does not prove common origin. Pediatric and postpubertal testicular tumors differ in GCNIS and 12p biology; SNP-array analysis also found several histogenetic routes and intratumoral genomic differences. Cross-sectional tumors cannot directly reconstruct the lineage.
Show evidence (1 reference)
"Our data indicate that GCTs may have various histogenesis and intratumoral genomic differences, which might provide important information for the identification of GCTs, especially for those with different histologic areas."
The SNP-array study directly supports diverse origins and within-tumor genomic differences.
Which genomic, epigenomic, transcriptional, and microenvironmental features reproducibly predict primary or acquired platinum resistance in YST, and do they generalize beyond ovarian cohorts?
The principal ovarian sequencing cohort associated MSI-related signatures and OVOL2 overexpression with resistance, but sample numbers were small and the authors called for independent validation. Relapsed tumors may reflect therapy selection, and findings cannot yet be generalized to pediatric, testicular, mediastinal, or CNS YST.
Show evidence (1 reference)
"This study lays a critical foundation for understanding key molecular aberrations in YSTs and developing related therapeutic strategies."
The authors characterize the work as a foundation rather than a validated clinical biomarker set.
What treatment effects and outcomes are attributable to a YST component itself after stratifying pure YST from mixed germ cell tumors by site, age, stage, component proportion, treatment, and somatically derived status?
Many clinical series combine pure YST, mixed tumors containing YST, and marker-defined putative YST. Overall-tumor behavior cannot be assigned to a microscopic component without component-resolved pathology and molecular analysis. Rare extragonadal sites and somatically derived YST are especially underpowered.
Show evidence (1 reference)
"Histology was pure, mixed, and putative in 129, 56, and 66 cases, respectively."
The largest pooled ovarian analysis illustrates the mixed evidentiary strata.
How can pediatric and adult, ovarian and testicular, extracranial and CNS staging/risk systems be harmonized for comparative YST research without erasing clinically meaningful site-specific distinctions?
Current care correctly stages the whole tumor using site-specific systems, but that complicates cross-study comparison. A harmonized research mapping needs central pathology, explicit pure-versus-mixed component annotation, and parallel retention of the native clinical stage.
Pathophysiology
8Primitive Endodermal Differentiation Program
YST is defined by differentiation toward primitive extraembryonic endoderm and related mesenchymal programs. This developmental identity explains its reticular-microcystic and other endodermal patterns, but does not establish one universal precursor cell for every gonadal, extragonadal, CNS, and somatically derived context.
Animal models
Testicular YST patient-derived xenograft
The human testicular YST xenograft preserves characteristic yolk-sac morphology together with the source tumor's AFP/SALL4 expression profile, reproducing assayable features of primitive endodermal differentiation.
Downstream
Extraembryonic endodermal differentiation produces the AFP-positive phenotype.
Show evidence (1 reference)
"Their complex nomenclature and histogenesis stress the fact that they are not a discrete entity, but represent a multifaceted group of neoplasms, for which the term primitive endodermal tumours would be more appropriate, accounting for their capacity to differentiate into various extraembryonal..."
The pathology review supports primitive-endodermal differentiation while explicitly rejecting treatment of all YST settings as one discrete entity.
AFP Synthesis and Secretion
YST cells synthesize AFP. After resection of an AFP-secreting tumor, serial serum AFP decay can report residual active tumor or preclinical recurrence; AFP is not specific to YST and tissue staining may be focal.
Show evidence (1 reference)
"Positive AFP staining was seen in the vast majority of YSTs (56 of 59 or 95%); however, 32 (54%) YSTs showed staining in less than 30% tumor cells."
A 59-case extragonadal YST series directly establishes frequent but often focal AFP expression.
Childhood Malignant-GCT Chromosomal-Imbalance Pattern
A 51-tumor study of germ cell tumors in children younger than 10 years included 33 malignant tumors of multiple histologies and sites; it was not a pure-YST cohort. At that childhood malignant-GCT level, most tumors lacked adult-type 12p gain and recurrent imbalances included distal 1p loss, 1q/20q gain, and 4q/6q deletion. This contextual pattern must not be assigned specifically to prepubertal testicular YST or generalized to all pediatric YST.
Downstream
Childhood malignant GCTs with this cohort-level copy-number pattern can converge on YST differentiation, but the imbalances are neither a YST-specific initiating set nor a resolved causal sequence.
Show evidence (2 references)
"With the exception of one testicular and two ovarian tumors, malignant GCTs in children do not show chromosomal gain of 12p, which is characteristic of GCTs in adult patients."
The 51-tumor pediatric CGH cohort directly separates childhood malignant GCT genetics from the adult 12p-gain pathway.
"Irrespective of the primary site, childhood GCTs show chromosomal imbalances of chromosome 1 (loss of distal 1p, gain of 1q), deletion of 4q and 6q as well as gain of 20q at a high frequency."
This provides the recurrent pediatric copy-number pattern without claiming that each alteration is universal or initiating.
Variable Epigenetic Reprogramming and Tumor-Suppressor Methylation
YSTs show heterogeneous imprinting/reprogramming states and more frequent tumor-suppressor-gene promoter methylation than seminoma or teratoma in one 45-tumor study. The methylation burden did not predict outcome, so it is a molecular characteristic rather than an established prognostic driver.
Show evidence (2 references)
"The methylation pattern of the H19 and SNRPN DMRs was total erasure in seminomas, mostly physiological in teratomas, and various in yolk sac tumors."
The tumor series directly demonstrates heterogeneous imprinting states in YST.
"Furthermore, we found that yolk sac tumors had a higher number of methylated TSGs than seminomas (P < 0.001) teratomas (P = 0.004) or other childhood tumors."
The comparative methylation analysis supports relative enrichment in YST.
Ovarian YST Somatic-Driver Landscape
Sequencing of 41 ovarian YST samples from 30 patients identified recurrent candidate mutations and copy-number drivers, including KRAS and KIT, and linked higher MSI scores and OVOL2 overexpression to cisplatin resistance. These findings are ovarian-cohort observations requiring external validation.
Show evidence (2 references)
"We identify somatic driver candidates, including significantly mutated genes KRAS and KIT and copy-number alteration drivers, including deleted ARID1A and PARK2, and amplified ZNF217, CDKN1B, and KRAS."
Whole-exome and RNA sequencing directly support the ovarian YST candidate-driver landscape.
"We silenced the OVOL2 expression using two independent small interfering RNAs (siRNAs) (Fig. 7B) and found that, in NOY1, the knockdown of OVOL2 dose- and time-dependently decreased cell viability in the presence of cisplatin."
The mechanistic link was tested by OVOL2 perturbation in the NOY1 YST cell line, so this is in-vitro evidence rather than a clinical association.
Somatic-Lineage Plasticity to YST Differentiation
YST-like differentiation associated with a non-germ-cell malignancy may arise from a malignant pluripotent somatic precursor. This is a distinct histogenetic setting and must not be represented as proof of a migrated primordial germ cell.
Downstream
A malignant somatic precursor may converge on YST-like primitive endodermal differentiation, but the proposed lineage route remains distinct from conventional germ-cell-derived YST and is not settled.
Show evidence (1 reference)
"YSTs associated with non-germ cell tumours probably originate from malignant pluripotent somatic stem cells."
The review explicitly frames somatic origin as probable, so the node is kept separate and not treated as a proven universal origin.
Histopathology
3
Reticular-Microcystic Pattern
The most common pattern is a reticular or microcystic network. YST is histologically heterogeneous, so absence of this pattern does not exclude it.
Show evidence (1 reference)
"The commonest pattern was reticular-microcystic, but macrocystic, papillary, endodermal sinus (Schiller-Duval bodies), labyrinthine, myxomatous, glandular, and solid patterns were also observed."
A pure pediatric testicular YST series documents both the dominant and variant patterns.
Schiller-Duval Bodies
Endodermal-sinus structures are characteristic when present but are only one pattern within the broader morphologic spectrum; diagnosis should not require them in every tumor.
Show evidence (1 reference)
"The commonest pattern was reticular-microcystic, but macrocystic, papillary, endodermal sinus (Schiller-Duval bodies), labyrinthine, myxomatous, glandular, and solid patterns were also observed."
The cohort places Schiller-Duval bodies within, rather than above, the full pattern spectrum.
SALL4-Positive OCT4-Negative Immunophenotype
Diffuse nuclear SALL4 is highly sensitive in extragonadal and pediatric YST. In the cited extragonadal series, OCT4 negativity separated YST from OCT4-positive germ cell components; AFP and glypican-3 were less diffuse than SALL4 in many tumors.
Show evidence (2 references)
"All 59 YSTs were negative for OCT4."
The extragonadal series directly supports OCT4 negativity.
"Strong SALL4 staining was seen in all 59 YSTs (in more than 90% tumor cells in 54 and 70% to 85% tumor cells in 5 YSTs)."
The series establishes diffuse SALL4 sensitivity in extragonadal YST.
Pathograph
Use the checkboxes to hide or show graph categories. Hover nodes for evidence and cross-linked metadata.
Phenotypes
5Genitourinary 1
Testicular neoplasm in infancy or early childhood
HP:0010788
Human Phenotype Ontology (HP)
Relation: this clinical feature is this phenotype
This clinical feature is Testicular neoplasm (HP:0010788), qualified as infantile onset. HP:0010788 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
"We report 33 pure yolk sac tumors of the testis from boys 5 to 71 months of age (mean 20.7 mo) diagnosed from 1918 to 2014."
A pure-YST series directly supports the early-childhood testicular context.
Metabolism 1
Elevated serum alpha-fetoprotein
Elevated circulating alpha-fetoprotein concentration
HP:0006254
Human Phenotype Ontology (HP)
Relation: this clinical feature is this phenotype
This clinical feature is Elevated circulating alpha-fetoprotein concentration (HP:0006254). HP:0006254 is a phenotype from the Human Phenotype Ontology.
Other 3
Ovarian mass
Ovarian neoplasm
HP:0100615
Human Phenotype Ontology (HP)
Relation: this clinical feature is this phenotype
This clinical feature is Ovarian neoplasm (HP:0100615). HP:0100615 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
"We present the case of a 21-year-old female who was admitted urgently due to a large abdominopelvic mass."
The mixed ovarian GCT case documents one mass presentation without establishing frequency.
Abnormal vaginal bleeding
HP:0034263
Human Phenotype Ontology (HP)
Relation: this clinical feature is this phenotype
This clinical feature is Abnormal vaginal bleeding (HP:0034263). HP:0034263 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
"We present a case of vaginal YST involving a one-year-old girl who presented with prolonged vaginal bleeding and urinary retention."
The pediatric vaginal YST case directly supports the site-specific symptom.
Mediastinal mass
HP:0033823
Human Phenotype Ontology (HP)
Relation: this clinical feature is this phenotype
This clinical feature is Mediastinal mass (HP:0033823). HP:0033823 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
"mediastinal forms are mostly restricted to young adult males"
The review supports the age/site pattern while the description preserves mixed-tumor scope.
Genetic Associations
6
Pediatric recurrent chromosomal imbalances
(Recurrent childhood malignant-GCT pattern of distal 1p loss, 1q/20q gain, and 4q/6q deletion in a mixed-site, mixed-histology cohort; not a prepubertal-testicular-YST-specific or obligatory driver set)
Show evidence (1 reference)
"Irrespective of the primary site, childhood GCTs show chromosomal imbalances of chromosome 1 (loss of distal 1p, gain of 1q), deletion of 4q and 6q as well as gain of 20q at a high frequency."
The evidence is pediatric malignant-GCT-level rather than isolated pure-YST sequencing.
Isochromosome 12p or other 12p gain
(Shared clonal hallmark of GCNIS-related/type II testicular germ cell tumors)
Show evidence (1 reference)
"A common molecular alteration in type II TGCTs is the presence of an isochromosome 12p or gain of 12p material."
The claim is explicitly restricted to the postpubertal/type II context.
KRAS
(Candidate recurrent somatic driver mutation and copy-number amplification in ovarian YST)
Show evidence (1 reference)
"We identify somatic driver candidates, including significantly mutated genes KRAS and KIT and copy-number alteration drivers, including deleted ARID1A and PARK2, and amplified ZNF217, CDKN1B, and KRAS."
The ovarian cohort identifies KRAS through both mutation and amplification analyses.
KIT
(Candidate recurrent somatic driver mutation in ovarian YST)
Show evidence (1 reference)
"We identify somatic driver candidates, including significantly mutated genes KRAS and KIT and copy-number alteration drivers, including deleted ARID1A and PARK2, and amplified ZNF217, CDKN1B, and KRAS."
The ovarian cohort identifies KIT as a significantly mutated candidate driver.
TP53
(Infrequently mutated in the studied ovarian YST cohort; not a universal absence)
Show evidence (1 reference)
"YSTs have very infrequent TP53 mutations, whereas the tumors from patients with abnormal gonadal development contain both KRAS and TP53 mutations."
The source supports rarity with a defined gonadal-development exception.
Klinefelter syndrome (47,XXY) association
(Strongly increased incidence of extragonadal germ cell tumor, particularly mediastinal disease, in a Klinefelter syndrome cohort; this is a mediastinal-GCT association rather than a YST-component-specific estimate)
Show evidence (1 reference)
"For EGCT, the crude age-standardised incidence ratio was 83.0 (95% CI, 2.1-460.5)."
The cohort quantifies the Klinefelter-extragonadal-GCT association, while the wide interval and one mediastinal event require cautious interpretation.
Medical Actions
10
Testicular Inguinal Orchiectomy
Radical inguinal orchiectomy establishes diagnosis and local control for a testicular tumor containing YST. Subsequent surveillance, staging, and systemic therapy differ between prepubertal-type pure YST and postpubertal GCNIS-related pure or mixed nonseminomatous tumors.
Show evidence (1 reference)
"Inguinal orchiectomy is the main diagnostic procedure, and is also curative for most localized tumors, while patients with unfavorable risk factors for recurrence, or those who are unable or unwilling to undergo close follow-up, may require adjuvant treatment."
The guideline supports the testicular operation without generalizing follow-up across ages and risks.
Ovarian Fertility-Sparing Surgery
Unilateral salpingo-oophorectomy with limited, site-appropriate staging is preferred when feasible for adolescent and young-adult ovarian malignant germ cell tumors containing YST. Operative extent depends on stage, tumor burden, fertility goals, and whether the lesion is pure YST, a mixed germ cell tumor, or YST differentiation in a somatic epithelial neoplasm.
Show evidence (1 reference)
"Fertility-sparing surgery, including unilateral salpingo-oophorectomy with minimal staging, is recommended for adolescent and young adult patients."
The review supports the ovarian site-specific fertility-preserving approach.
Postpubertal and Adult Risk-Adapted BEP Chemotherapy
BEP is a cisplatin-based backbone for postpubertal/adult malignant germ cell tumors containing YST, with cycles and alternatives selected by site, anatomic stage, marker kinetics, and IGCCCG group. It also has an ovarian role, but this record does not assign adult BEP to every pediatric or CNS setting.
Show evidence (2 references)
"Patients with persistent markers after orchiectomy or advanced disease at diagnosis should be staged and classified according to the IGCCCG prognostic classification. BEP is the most recommended chemotherapy, but other schedules such as EP or VIP may be used to avoid bleomycin in some patients."
The current guideline ties postpubertal testicular systemic treatment to IGCCCG context.
"The bleomycin/etoposide/cisplatin regimen remains the first-line therapy."
The ovarian malignant-germ-cell-tumor review explicitly supports an ovarian BEP role.
Pediatric Compressed PEB Chemotherapy
Selected pediatric protocols use cisplatin, etoposide, and bleomycin (PEB), including compressed three-cycle salvage for residual or recurrent stage I ovarian malignant germ cell tumors. This protocol evidence includes tumors containing YST and should not be extrapolated to every pediatric site or stage.
Show evidence (1 reference)
"In those with residual or recurrent disease, chemotherapy with compressed PEB (cisplatin, etoposide, and bleomycin) was initiated every 3 weeks for three cycles."
This directly supports the context-specific pediatric compressed-PEB record.
Pediatric JEB Chemotherapy
Carboplatin, etoposide, and bleomycin (JEB) is a pediatric extracranial-GCT protocol option supported by a UK study of patients aged 0-16 years that included 107 YSTs. Its carboplatin backbone is specific to protocols and jurisdictions, not interchangeable with adult BEP or CNS regimens by default.
Show evidence (2 references)
"The remaining 184 patients had germinoma (n = 20), malignant teratoma (n = 55), embryonal carcinoma (n = 1), yolk sac tumor (n = 107), or choriocarcinoma (n = 1). Forty-seven patients were treated with surgery alone, and 137 patients received JEB."
The pediatric study directly documents the histologic mixture and JEB exposure.
"JEB treatment induced significant tumor regression without causing clinically relevant body weight loss."
The testicular YST xenograft provides preclinical response evidence; it does not substitute for the pediatric clinical protocol evidence above.
Primary Mediastinal Poor-Risk Cisplatin-Based Therapy
Primary mediastinal nonseminomatous GCT is an IGCCCG poor-risk setting. The cited review recommends individualized dose-intensified or high-dose upfront chemotherapy and expert-center referral. This whole-tumor risk category is not evidence that every mediastinal YST component independently has the same prognosis.
Show evidence (1 reference)
"however, due to their very poor prognosis patients with non-seminomatous mediastinal GCT should receive a dose-intensified or high-dose chemotherapy approach upfront on an individual basis and should thus be referred to expert centers"
The systematic review explicitly supports individualized intensified therapy and expert-center referral.
Post-Chemotherapy Mediastinal Residual-Mass Resection
Resect the residual mediastinal mass after platinum-based chemotherapy for primary mediastinal nonseminomatous GCT when technically feasible, using an experienced high-volume multidisciplinary center. Management follows the residual whole tumor, which may be mixed, rather than a YST component alone.
Show evidence (1 reference)
"All patients with primary mediastinal non-seminoma should undergo surgical resection of the mediastinal mass post-chemotherapy. These are complex surgeries and require expert surgeons in high-volume centers."
The review directly supports site-specific residual-mass surgery.
Component-Directed Therapy for Somatically Derived Ovarian YST
When a YST component arises with an ovarian epithelial malignancy, adjuvant platinum-based therapy should be selected to address both the epithelial carcinoma and germ-cell-like components. Evidence is sparse and no ideal regimen is established, so this must not be managed as routine pure YST without review.
Show evidence (1 reference)
"When YST mixed with epithelial cancer components, adjuvant chemotherapy regimen should include platinum-based chemotherapy aiming at both epithelial ovarian cancer and germ cell tumors."
The review offers component-directed guidance, but its small case base does not establish a single regimen.
Surveillance After Complete Stage I Resection
Selected children with completely resected stage I ovarian or testicular malignant germ cell tumors can undergo intensive marker/imaging surveillance with prompt salvage chemotherapy at recurrence. This is protocol-defined and is not a blanket surgery-only recommendation for every stage I adult or site.
Show evidence (1 reference)
"Fifty percent of patients with stage I pediatric MOGCT can be spared chemotherapy; treatment for those who experience recurrence preserves OS."
The prospective pediatric ovarian study supports a selected surveillance strategy.
Neoadjuvant Chemotherapy for Selected Advanced Ovarian YST
For advanced ovarian YST with high tumor burden or poor operative tolerance, neoadjuvant chemotherapy followed by interval surgery is an option. Evidence is retrospective and includes mixed tumors containing YST elements.
Show evidence (1 reference)
"For patients with advanced-stage ovarian yolk sac tumor, neoadjuvant chemotherapy followed by interval surgery is an alternative option, especially for those who cannot tolerate the primary debulking surgery because of high tumor burden and vulnerable status."
The 40-patient retrospective comparison supports this selected alternative.
Biochemical Markers
4
Serum Alpha-Fetoprotein
Pathograph Readouts
Readout Of
AFP Synthesis and Secretion
Positive
Diagnostic
Show evidence (2 references)
"In group 1, which had complete resection and no recurrence during follow-up (n = 13), the AHL of AFP was 4.0 +/- 0.9 days."
This supplies the observed post-resection AFP decay in children without recurrence.
"In group 2, which had incomplete resection or recurrence during follow-up (n = 5), the AHL of AFP was 24.8 +/- 20 days, significantly longer than that of group 1 (P = 0.0026)."
This supports delayed AFP clearance as a residual/recurrent-tumor signal.
Show evidence (1 reference)
"We found that it was not until 8 months of age that the normal AFP level in infants approached adult level."
Normal-infant longitudinal data establish why an adult AFP cutoff is inappropriate in early infancy.
SALL4 Expression
Show evidence (1 reference)
"In contrast to AFP and glypican-3, SALL4 staining in more than 90% of the tumor cells was seen in all 22 pediatric YSTs (100% sensitivity) (P < 0.001 for both SALL4 vs. AFP and SALL4 vs. glypican-3)."
A pediatric YST series directly supports high sensitivity and diffuse staining.
FOXA2 Nuclear Expression
Show evidence (2 references)
"FoxA2 was positive in all YSTpt (24 of 24) and all but one (23 of 24) exhibited 2+/3+ stain"
The postpubertal-type testicular cohort directly establishes universal FOXA2 positivity and moderate-to-diffuse staining in 23 of 24 tumors.
"FoxA2 is a highly sensitive and specific biomarker that supports the diagnosis of YSTpt. FoxA2 is superior to GPC3 and AFP, especially in rare and difficult-to-diagnose histological patterns of YSTpt, but mature glands of Tpt could represent a potential diagnostic pitfall."
The authors' conclusion supports the comparative diagnostic role while preserving the tested postpubertal-type scope and teratoma pitfall.
Glypican-3 Expression
Show evidence (1 reference)
"Although all 59 YSTs showed positive glypican-3 staining, 18 (30%) showed staining in less than 30% tumor cells, and additional 10 (17%) showed staining in between 30% and 60% tumor cells."
This establishes frequent but variably extensive glypican-3 staining.
Diagnosis
3
Integrated Histopathology and Immunohistochemistry
Diagnose YST by architecture and cytology integrated with an antibody panel. SALL4 was strong and diffuse in the cited 59-case extragonadal series, whereas AFP and glypican-3 were often focal or variable. SALL4 is also expressed by other primitive germ cell tumors; OCT4 negativity helps distinguish YST from germinoma/dysgerminoma and embryonal carcinoma. No single stain substitutes for morphology.
Histopathologic Examination
NCIT:C18190
NCI Thesaurus (NCIT)
Show evidence (2 references)
"Our results indicate that SALL4 is a novel sensitive (100% sensitivity) diagnostic marker for extragonadal YSTs."
A large extragonadal series supports SALL4 as a sensitive panel component.
"Positive AFP staining was seen in the vast majority of YSTs (56 of 59 or 95%); however, 32 (54%) YSTs showed staining in less than 30% tumor cells. Although all 59 YSTs showed positive glypican-3 staining, 18 (30%) showed staining in less than 30% tumor cells, and additional 10 (17%) showed..."
The same series directly shows why AFP and glypican-3 should not be called uniformly diffuse.
Serum AFP Measurement and Kinetic Follow-up
Follow serum AFP serially after resection of an AFP-secreting tumor. Delayed clearance supports residual active tumor and AFP half-life may detect preclinical recurrence. In infants, compare AFP with age-adjusted physiologic ranges before attributing an elevation to tumor; interpretation remains contextual rather than diagnostic alone.
Alpha-fetoprotein Measurement
NCIT:C74732
NCI Thesaurus (NCIT)
Markers: AFP
Show evidence (3 references)
"The increased AHL of AFP indicated residual active tumor after surgical resection."
Serial AFP kinetics directly report residual active tumor in the pediatric study.
"The AHL of AFP may be more sensitive than serial monitoring of AFP in detecting preclinical recurrence after surgical resection of AFP-secreting tumors."
The pediatric study explicitly supports the post-resection recurrence use.
"We found that it was not until 8 months of age that the normal AFP level in infants approached adult level."
Normal infant data require age-adjusted rather than adult AFP thresholds.
Site-Specific Staging and Risk Classification
Stage and risk-classify the complete germ cell tumor context rather than the YST component in isolation. Advanced postpubertal testicular germ cell tumors use IGCCCG risk classification, primary mediastinal nonseminoma is assigned to the IGCCCG poor-prognosis group, and the cited ovarian YST cohorts use FIGO stage. The pediatric evidence here is limited to stage I ovarian malignant germ cell tumors and does not establish a universal pediatric extracranial or CNS YST staging convention.
staging procedure
NCIT:C18020
NCI Thesaurus (NCIT)
Show evidence (5 references)
"Although germ cell tumors (GCT) supposedly share the same cell type of origin, their clinical course differs considerably depending on tumor site and histology."
The pediatric cohort supports preserving site and histology in clinical interpretation.
"Patients with persistent markers after orchiectomy or advanced disease at diagnosis should be staged and classified according to the IGCCCG prognostic classification."
This supports IGCCCG risk classification in advanced postpubertal testicular disease.
"EGCT patients are classified according to the IGCCCG classification. Consecutively, all mediastinal non-seminomatous EGCT patients belong to the "poor prognosis" group."
The systematic review supplies the mediastinal nonseminomatous risk context; it is not a YST-component-specific stage.
+ 2 more references
Progression
5Pediatric population-based survival
In SEER 2000-2018, pediatric YST had 92.2% 3-year and 90.3% 5-year overall survival; older age and extragonadal site were adverse in that analysis.
Show evidence (2 references)
"Overall survival rates for all patients were 92.2% at 3-year and 90.3% at 5-year, respectively."
The population-based cohort provides YST-specific overall survival.
"Furthermore, patients with extra-gonadal YST have a lower survival rate than those with gonadal YST."
This supports site-stratified prognosis rather than one uniform outcome.
Platinum-treated ovarian YST outcome
A pooled international trial dataset included pure YST, mixed tumors with a YST component, and AFP-defined putative YST. The combined 5-year EFS was 91% and OS 96%; this is not a pure-YST-only estimate.
Show evidence (2 references)
"The overall 5-year event-free survival and overall survival was 91% (95% confidence interval, 87%-94%) and 96% (92%-98%), respectively."
The pooled ovarian YST dataset directly reports the combined outcomes.
"Histology was pure, mixed, and putative in 129, 56, and 66 cases, respectively."
This makes the component mixture behind the outcome estimate explicit.
Stage I ovarian surveillance and early relapse
Surgery followed by surveillance spared chemotherapy in about half of a small pediatric stage I malignant ovarian GCT cohort dominated by YST, but recurrences were early and AFP-positive; salvage preserved overall survival.
Show evidence (2 references)
"After a median follow-up of 42 months, 12 patients had evidence of persistent or recurrent disease (4-year EFS, 52%; 95% CI, 31% to 69%)."
The prospective COG study quantifies recurrence under stage I surveillance.
"Eleven of 12 patients experiencing relapse received successful salvage chemotherapy (4-year OS, 96%; 95% CI, 74% to 99%)."
This supports the high salvage-supported overall survival.
Stage I pediatric testicular outcome
In pooled prospective trials, all evaluable stage I tumors contained YST elements; no deaths occurred, while age at least 12 years and higher pT stage predicted events. This is not a pure prepubertal-YST-only cohort.
Show evidence (2 references)
"Among patients with evaluable histopathology, yolk sac tumor elements were present in all patients and lymphovascular invasion in 51% of patients."
This defines the YST-containing nature of the stage I cohort.
"Over a median follow-up of 56 months, no patients died, and 25 patients (24%) experienced an event (median event-free survival not reached)."
This separates excellent survival from nonzero relapse/event risk.
Mediastinal GCT-associated hematologic malignancy
In an international retrospective series, 17 of 287 patients with primary mediastinal nonseminomatous germ cell tumors developed a hematologic disorder. The median onset was 6 months and median survival after the blood cancer diagnosis was 5 months. This severe mediastinal-GCT syndrome is not automatically attributable to a YST component in every mixed tumor.
Show evidence (2 references)
"A hematologic disorder was observed in 17 patients with germ cell tumors."
The cohort makes the hematologic risk substantive and confines it to primary mediastinal nonseminomatous GCT rather than all YST.
"The median time to onset of hematologic neoplasia was 6 months (range, 0-47 months), and the median survival after diagnosis of the hematologic disorder was 5 months (range, 0-16 months)."
The series directly quantifies the early onset and poor outcome.
Prevalence
1Children and adolescents in the United States SEER registries, 2000-2018
A population-based study identified 520 pediatric YST cases in SEER over 19 diagnosis years. This is a registry case count, not a prevalence or incidence denominator; no population rate is inferred here.
Show evidence (1 reference)
"A total of 520 YST patients were identified."
This is retained as an occurrence anchor without manufacturing a rate.
Differential Diagnoses
5Conditions with similar clinical presentations that must be differentiated from Yolk Sac Tumor:
Juvenile granulosa cell tumor of the testis
Overlapping Features
In an infant with a testicular tumor, juvenile granulosa cell tumor overlaps in age and some morphology but is a sex-cord stromal tumor. Architecture and an appropriate immunohistochemical panel distinguish it from YST.
Distinguishing Features
- The cited pure testicular YST series notes morphologic overlap with juvenile granulosa cell tumor.
- In that series, juvenile granulosa cell tumor occurred at a slightly younger age and had distinctive features.
Show evidence (1 reference)
"It is crucial that this tumor be distinguished from the juvenile granulosa cell tumor, which occurs at a slightly younger age and has distinctive features, although there may be some morphologic overlap."
The pure pediatric testicular YST series directly names the differential.
Mature teratoma
Overlapping Features
Pediatric teratoma can occur in the same age/site spectrum. Diffuse SALL4 staining supports YST over mature teratoma when morphology is challenging.
Distinguishing Features
- Diffuse nuclear SALL4 in the malignant primitive component favors YST.
- Mature somatic tissues without a malignant YST component favor mature teratoma.
Show evidence (1 reference)
"SALL4 is a sensitive marker for pediatric YSTs and it can be used to distinguish them from mature teratomas."
The 22-YST/10-teratoma comparison directly supports this distinction.
Ovarian clear cell carcinoma
Overlapping Features
Ovarian YST and clear cell carcinoma can overlap morphologically. Diffuse nuclear SALL4 favors YST in this site, while an integrated epithelial-marker profile and morphology support clear cell carcinoma; SALL4 is not a universal germ-cell-subtype discriminator.
Distinguishing Features
- Diffuse SALL4 with compatible endodermal-sinus or reticular morphology favors YST.
- In the cited comparison, CK7 and EMA were positive in all 45 clear cell carcinomas but only focally positive in 3 and 4 YSTs, respectively.
Show evidence (2 references)
"SALL4 is particularly useful in distinguishing YST from CCC and better than AFP, glypican-3, CK7, and EMA."
The ovarian immunohistochemical comparison directly addresses this differential.
"Three (10%) and 4 (14%) YSTs show focal (<2% tumor cells) CK7 and EMA staining, respectively. CK7 and EMA are positive in all 45 CCCs but 3 (7%) and 1 (2%) cases show staining in less than 30% tumor cells, respectively."
The ovarian series supplies the exact CK7 and EMA comparison.
CNS germinoma or embryonal carcinoma component
Overlapping Features
In primary CNS germ cell tumors, germinoma and embryonal carcinoma can also express diffuse SALL4. Strong OCT4 supports those CNS components, whereas other germ cell tumors in the cited CNS series were OCT4-negative; morphology and a full panel remain required.
Distinguishing Features
- In a primary CNS germ cell tumor, strong OCT4 with compatible morphology favors germinoma or embryonal carcinoma.
- In that CNS differential, OCT4 negativity does not identify YST without compatible morphology and a full panel.
Show evidence (1 reference)
"All germinomas and embryonal carcinomas showed strong OCT4 staining (4+ in all except 1 germinoma with 3+), whereas other germ cell tumors were negative."
The CNS germ-cell-tumor series shows why SALL4 alone cannot separate these primitive components and supports OCT4 as a discriminator.
Non-germ-cell carcinoma with YST-like morphology or differentiation
Overlapping Features
Endometrial, gastric, lung, and other somatic carcinomas may show endodermal morphology or a somatically derived YST component. Patient age, anatomic setting, associated conventional carcinoma, molecular profile, and the full immunophenotypic panel determine whether this is a germ-cell-derived YST.
Distinguishing Features
- The cited review states that endodermal somatic differentiation may reproduce pulmonary, intestinal, and hepatic tissues.
- It also reports morphologic identity with some embryonal-type endodermal gastric and lung carcinomas.
Show evidence (1 reference)
"Endodermal somatic differentiation reproduces pulmonary, intestinal and hepatic tissues and are identical with some, embryonal-type endodermal, gastric and lung carcinomas, which are indistinguishable from YSTs."
The pathology review directly documents the morphologic overlap.
Related Datasets
3
MicroRNA-371-373 cluster and methylome analysis suggests that a subset of “somatic-type” malignancies arising in germ cell tumors may originate in yolk sac tumor components
geo:GSE281147
Background: Somatic-type malignancies (SM) arising in germ cell tumors (GCTs) represent aggressive and chemoresistant neoplasms frequently occurring as metastases after chemotherapy. Historically, SM have been interpreted as originating in teratoma; however, recent observations suggest that a subset may derive from yolk sac tumor. In this study, we evaluate the relationship between conventional histologic types of GCT and SM of germ cell origin by assessing expression of miR-371~373 and genomic methylation.
Identified by GEO DataSets index search for Yolk Sac Tumor (scripts/discover_datasets.py); accession and metadata verified against NCBI E-utilities on 2026-08-01. Title, sample count, and organism are GEO's own values.
Genomic Landscape, Evolution and Chemoresistance of Yolk Sac Tumors
geo:GSE169733
This GEO series is linked to the ovarian YST sequencing study. The cached summary does not establish a sample count for a processed-expression subset or raw-data availability, so neither is asserted here. It should not be treated as representative of every pediatric, testicular, mediastinal, CNS, or somatically derived YST.
Show evidence (1 reference)
"Here we characterized 41 clinical tumor samples (and related normal samples) from 30 YST patients, with distinct responses to cisplatin_x001f__x001F_-based chemotherapy, through a combination of whole-exome and RNA sequencing."
The GEO summary establishes the linked human ovarian YST sequencing cohort.
Chromatin-immunoprecipitation followed by sequencing (ChIPseq) of SOX17 and FOXA2 in yolk-sac tumor cell lines
geo:GSE276475
ChIPseq of SOX17 and FOXA2 in yolk-sac tumor cell lines GCT72 and 1411H
Identified by GEO DataSets index search for Yolk Sac Tumor (scripts/discover_datasets.py); accession and metadata verified against NCBI E-utilities on 2026-08-01. Title, sample count, and organism are GEO's own values.
Clinical Trials
1
NCT03067181
PHASE_III
This phase III germ cell tumor trial studies active surveillance after removal of low-risk tumors and compares carboplatin with cisplatin for metastatic standard-risk disease. The generated cache does not expose YST-specific stage, site, or mixed-tumor eligibility, so none is asserted here and results must not be interpreted as YST-specific without histology- and site-resolved reporting.
Show evidence (1 reference)
"The trial studies whether carboplatin or cisplatin is the preferred chemotherapy to use in treating metastatic standard risk germ cell tumors."
The current registry summary defines the randomized platinum question.
Animal Models
1
Testicular YST patient-derived xenograft
Patient-derived xenograft
Testicular YST tissue was serially passaged in immunodeficient NPG and BALB/c nude mice, retaining Schiller-Duval morphology and AFP/SALL4 expression. JEB sensitivity was tested in vivo and ex vivo. This single patient-derived preclinical model does not establish clinical efficacy or represent ovarian, mediastinal, CNS, mixed, or somatically derived YST.
Species
Mus musculus
Genotype
Patient-derived xenografts from a pediatric testicular yolk sac tumor
Pathograph links
Primitive Endodermal Differentiation Program
The human testicular YST xenograft preserves characteristic yolk-sac morphology together with the source tumor's AFP/SALL4 expression profile, reproducing assayable features of primitive endodermal differentiation.
Limitations: This is a single pediatric testicular tumor propagated subcutaneously in immunodeficient mice. Morphology and two diagnostic proteins support the link, but do not establish fidelity across other YST sites, ages, mixed tumors, immune contexts, or the full differentiation program.
Show evidence (1 reference)
"H&E staining confirmed preservation of characteristic yolk sac morphology, including Schiller-Duval bodies. Immunohistochemical analysis demonstrated consistent expression of AFP and SALL4 in PDX tumors, mirroring the diagnostic profile of the original specimen."
Preserved morphology plus AFP/SALL4 expression directly grounds the model-to-mechanism link; moderate fidelity reflects its single-patient, immunodeficient xenograft context.
Show evidence (2 references)
"The patient-derived TYST tumor tissues exhibited higher tumorigenicity in NPG and BALB/c nude mice, maintaining stability through serial passaging."
The study directly establishes and serially passages the mouse PDX.
"Immunohistochemical analysis demonstrated consistent expression of AFP and SALL4 in PDX tumors, mirroring the diagnostic profile of the original specimen."
The PDX preserved the source tumor's key protein-expression profile.
Source YAML
click to showname: Yolk Sac Tumor
creation_date: "2026-06-15T00:00:00Z"
category: Complex
description: >-
Yolk sac tumor (YST; endodermal sinus tumor) is a malignant neoplasm defined
by primitive extraembryonic/endodermal differentiation rather than by one
anatomic site or one molecular route. It occurs as a pure tumor or as a
component of a mixed germ cell tumor in gonadal, extragonadal, and central
nervous system sites; morphologically similar, somatically derived YST
differentiation can also arise in a non-germ-cell carcinoma. These settings
are not biologically interchangeable. In particular, prepubertal-type
testicular YST is generally unrelated to germ cell neoplasia in situ (GCNIS)
and usually lacks 12p gain, whereas postpubertal-type testicular YST is a
GCNIS-related component of type II germ cell tumor and may belong to a
12p-gained clone. Diagnosis integrates morphology, immunohistochemistry, and
serum alpha-fetoprotein (AFP); staging and management remain site- and
age-specific.
disease_term:
preferred_term: yolk sac tumor
term:
id: MONDO:0005744
label: yolk sac tumor
synonyms:
- endodermal sinus tumor
- yolk sac carcinoma
parents:
- germ cell tumor
- nonseminomatous germ cell tumor
notes: >-
Scope guardrail: this entry describes the YST histology across sites. A YST
component does not make every clinical or molecular observation from the
whole mixed germ cell tumor attributable to that component. Component-level
claims are included only when the cited study identifies YST directly;
group-level germ cell tumor evidence is labelled partial or used only for clinical
context. Somatically derived YST differentiation is retained as a distinct
context and is not presented as a primordial-germ-cell-derived tumor.
has_subtypes:
- name: Prepubertal testicular YST
display_name: Prepubertal-type testicular yolk sac tumor
subtype_term:
preferred_term: Testicular Yolk Sac Tumor, Prepubertal-Type
term:
id: NCIT:C192100
label: Testicular Yolk Sac Tumor, Prepubertal-Type
description: >-
Usually a pure testicular tumor in infants and young boys. It belongs to
the GCNIS-unrelated/type I testicular germ cell tumor pathway and is
molecularly distinct from postpubertal-type YST.
- name: Postpubertal testicular YST
display_name: Postpubertal-type testicular yolk sac tumor
subtype_term:
preferred_term: Testicular Yolk Sac Tumor, Postpubertal-Type
term:
id: NCIT:C192099
label: Testicular Yolk Sac Tumor, Postpubertal-Type
description: >-
A GCNIS-related/type II testicular germ cell tumor histology, usually
encountered as one component of a mixed nonseminomatous tumor. Claims about
the entire mixed tumor are not automatically assigned to its YST component.
- name: Ovarian YST
display_name: Ovarian yolk sac tumor
subtype_term:
preferred_term: ovarian yolk sac tumor
term:
id: MONDO:0006344
label: ovarian yolk sac tumor
description: >-
A malignant ovarian germ cell tumor affecting children, adolescents, and
young adults. Pure, mixed, and AFP-defined putative YST cohorts must be
distinguished when interpreting treatment and outcome data.
- name: Pediatric extragonadal YST
display_name: Pediatric extracranial extragonadal yolk sac tumor
review_notes: >-
No subtype_term is bound because neither NCIT:C27364 (Childhood Yolk Sac
Tumor) nor NCIT:C68632 (Childhood Malignant Extragonadal Germ Cell Tumor)
captures both the YST histology and the pediatric extracranial extragonadal
site boundary. Substituting either broader class would erase part of this
subtype's scope.
description: >-
Includes sacrococcygeal, retroperitoneal, vaginal, and other extracranial
sites in children. Site modifies presentation, staging, and outcome.
- name: Mediastinal postpubertal YST
display_name: Mediastinal postpubertal-type yolk sac tumor
review_notes: >-
No subtype_term is bound because MONDO:0023726 and NCIT:C6443 both denote
mediastinal yolk sac tumor without the postpubertal/type II boundary used
here. Those broader terms would also include pediatric mediastinal disease,
which this subtype explicitly excludes.
description: >-
Usually part of a primary mediastinal nonseminomatous germ cell tumor in an
adolescent or adult male. This setting has distinct poor-risk management,
a strong association with Klinefelter syndrome, and a specific risk of
clonally related hematologic malignancy. It should not be conflated with
pediatric mediastinal type I germ cell tumors or with gonadal YST, and the
mediastinal-germ-cell-tumor risks are not automatically YST-component-specific.
- name: CNS YST
display_name: Central nervous system yolk sac tumor
subtype_term:
preferred_term: yolk sac tumor of central nervous system
term:
id: MONDO:0016739
label: yolk sac tumor of central nervous system
description: >-
An AFP-secreting nongerminomatous CNS germ cell tumor component. CNS
tumor-marker thresholds, staging, radiation fields, and protocols are distinct
from extracranial disease and are curated in the CNS germ cell tumor entry.
- name: Somatically derived YST
display_name: Somatically derived yolk sac tumor differentiation
review_notes: >-
No subtype_term is bound because NCIT:C178523 describes the opposite
direction, a germ-cell-derived yolk sac tumor that transforms into a
somatic-type malignancy. It is not an exact term for YST differentiation
arising from a non-germ-cell malignant precursor.
description: >-
YST morphology and immunophenotype arising in association with a
non-germ-cell malignancy. The probable histogenesis is lineage plasticity of
a malignant somatic precursor rather than a conventional germ cell tumor.
pathophysiology:
- name: Primitive Endodermal Differentiation Program
biological_scale: CELLULAR
description: >-
YST is defined by differentiation toward primitive extraembryonic endoderm
and related mesenchymal programs. This developmental identity explains its
reticular-microcystic and other endodermal patterns, but does not establish
one universal precursor cell for every gonadal, extragonadal, CNS, and
somatically derived context.
biological_processes:
- preferred_term: abnormal extraembryonic endodermal differentiation
modifier: ABNORMAL
term:
id: GO:0030154
label: cell differentiation
evidence:
- reference: PMID:22008025
reference_title: Yolk sac tumours revisited. A review of their many faces and names.
supports: SUPPORT
evidence_source: OTHER
snippet: >-
Their complex nomenclature and histogenesis stress the fact that they are
not a discrete entity, but represent a multifaceted group of neoplasms,
for which the term primitive endodermal tumours would be more appropriate,
accounting for their capacity to differentiate into various
extraembryonal and somatic cell types.
explanation: >-
The pathology review supports primitive-endodermal differentiation while
explicitly rejecting treatment of all YST settings as one discrete entity.
downstream:
- target: AFP Synthesis and Secretion
causal_link_type: DIRECT
description: Extraembryonic endodermal differentiation produces the AFP-positive phenotype.
evidence:
- reference: PMID:22008025
reference_title: Yolk sac tumours revisited. A review of their many faces and names.
supports: SUPPORT
evidence_source: OTHER
snippet: Only AFP and glypican-3 are characteristic immunohistochemical markers.
explanation: >-
Marker expression is characteristic of the differentiation program;
the review does not experimentally establish the temporal causal edge.
- name: AFP Synthesis and Secretion
biological_scale: MOLECULAR
description: >-
YST cells synthesize AFP. After resection of an AFP-secreting tumor, serial
serum AFP decay can report residual active tumor or preclinical recurrence;
AFP is not specific to YST and tissue staining may be focal.
gene_products:
- preferred_term: alpha-fetoprotein
term:
id: NCIT:C16278
label: Alpha-Fetoprotein
evidence:
- reference: PMID:19574883
reference_title: >-
Diagnostic utility of SALL4 in extragonadal yolk sac tumors: an
immunohistochemical study of 59 cases with comparison to placental-like
alkaline phosphatase, alpha-fetoprotein, and glypican-3.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Positive AFP staining was seen in the vast majority of YSTs (56 of 59 or
95%); however, 32 (54%) YSTs showed staining in less than 30% tumor cells.
explanation: >-
A 59-case extragonadal YST series directly establishes frequent but often
focal AFP expression.
- name: Childhood Malignant-GCT Chromosomal-Imbalance Pattern
biological_scale: MOLECULAR
description: >-
A 51-tumor study of germ cell tumors in children younger than 10 years
included 33 malignant tumors of multiple histologies and sites; it was not
a pure-YST cohort. At that childhood malignant-GCT level, most tumors lacked
adult-type 12p gain and recurrent imbalances included distal 1p loss,
1q/20q gain, and 4q/6q deletion. This contextual pattern must not be assigned
specifically to prepubertal testicular YST or generalized to all pediatric YST.
evidence:
- reference: PMID:11528555
reference_title: Genetic analysis of childhood germ cell tumors with comparative genomic hybridization.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
With the exception of one testicular and two ovarian tumors, malignant
GCTs in children do not show chromosomal gain of 12p, which is
characteristic of GCTs in adult patients.
explanation: >-
The 51-tumor pediatric CGH cohort directly separates childhood malignant
GCT genetics from the adult 12p-gain pathway.
- reference: PMID:11528555
reference_title: Genetic analysis of childhood germ cell tumors with comparative genomic hybridization.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Irrespective of the primary site, childhood GCTs show chromosomal
imbalances of chromosome 1 (loss of distal 1p, gain of 1q), deletion of 4q
and 6q as well as gain of 20q at a high frequency.
explanation: >-
This provides the recurrent pediatric copy-number pattern without
claiming that each alteration is universal or initiating.
downstream:
- target: Primitive Endodermal Differentiation Program
causal_link_type: UNKNOWN
description: >-
Childhood malignant GCTs with this cohort-level copy-number pattern can
converge on YST differentiation, but the imbalances are neither a
YST-specific initiating set nor a resolved causal sequence.
evidence:
- reference: PMID:11528555
reference_title: Genetic analysis of childhood germ cell tumors with comparative genomic hybridization.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Irrespective of the primary site, childhood GCTs show chromosomal
imbalances of chromosome 1 (loss of distal 1p, gain of 1q), deletion of
4q and 6q as well as gain of 20q at a high frequency.
explanation: >-
The cohort supports a childhood malignant-GCT molecular route, while
the unknown edge type avoids claiming a specific differentiation mechanism.
- name: Postpubertal GCNIS-Related 12p-Gain Pathway
biological_scale: MOLECULAR
description: >-
Postpubertal-type testicular YST belongs to the GCNIS-related/type II germ
cell tumor family. Isochromosome 12p or other 12p gain is common in that
family and is thought to arise during progression from GCNIS to invasive
tumor; the lesion belongs to the shared clone, not uniquely to the YST component.
evidence:
- reference: PMID:41384700
reference_title: "Molecular pathology of testicular germ cell tumours: an update for practicing pathologists."
supports: SUPPORT
evidence_source: OTHER
snippet: >-
Type II TGCTs are the only GCNIS-related tumours in this classification
and include seminomas, embryonal carcinoma, choriocarcinoma, yolk-sac
tumour and teratoma of postpubertal type.
explanation: >-
The current molecular-pathology review places postpubertal YST in the
GCNIS-related type II family.
- reference: PMID:41384700
reference_title: "Molecular pathology of testicular germ cell tumours: an update for practicing pathologists."
supports: SUPPORT
evidence_source: OTHER
snippet: >-
A common molecular alteration in type II TGCTs is the presence of an
isochromosome 12p or gain of 12p material.
explanation: >-
This supports 12p gain at the type II tumor-family level, with the scope
restriction preserved in the node description.
downstream:
- target: Primitive Endodermal Differentiation Program
causal_link_type: UNKNOWN
description: >-
In postpubertal testicular disease, a GCNIS-related type II clone with 12p
gain can differentiate into a YST component; 12p gain is shared across the
tumor family and is not a YST-lineage-specific causal lesion.
evidence:
- reference: PMID:41384700
reference_title: "Molecular pathology of testicular germ cell tumours: an update for practicing pathologists."
supports: SUPPORT
evidence_source: OTHER
snippet: >-
Type II TGCTs are the only GCNIS-related tumours in this classification
and include seminomas, embryonal carcinoma, choriocarcinoma, yolk-sac
tumour and teratoma of postpubertal type.
explanation: >-
The review places postpubertal YST in this upstream type II route, but
does not resolve the intervening lineage mechanism.
- name: Variable Epigenetic Reprogramming and Tumor-Suppressor Methylation
biological_scale: MOLECULAR
description: >-
YSTs show heterogeneous imprinting/reprogramming states and more frequent
tumor-suppressor-gene promoter methylation than seminoma or teratoma in one
45-tumor study. The methylation burden did not predict outcome, so it is a
molecular characteristic rather than an established prognostic driver.
evidence:
- reference: PMID:19245437
reference_title: >-
Yolk sac tumor but not seminoma or teratoma is associated with abnormal
epigenetic reprogramming pathway and shows frequent hypermethylation of
various tumor suppressor genes.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
The methylation pattern of the H19 and SNRPN DMRs was total erasure in
seminomas, mostly physiological in teratomas, and various in yolk sac tumors.
explanation: The tumor series directly demonstrates heterogeneous imprinting states in YST.
- reference: PMID:19245437
reference_title: >-
Yolk sac tumor but not seminoma or teratoma is associated with abnormal
epigenetic reprogramming pathway and shows frequent hypermethylation of
various tumor suppressor genes.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Furthermore, we found that yolk sac tumors had a higher number of
methylated TSGs than seminomas (P < 0.001) teratomas (P = 0.004) or other
childhood tumors.
explanation: The comparative methylation analysis supports relative enrichment in YST.
- name: Ovarian YST Somatic-Driver Landscape
biological_scale: MOLECULAR
description: >-
Sequencing of 41 ovarian YST samples from 30 patients identified recurrent
candidate mutations and copy-number drivers, including KRAS and KIT, and
linked higher MSI scores and OVOL2 overexpression to cisplatin resistance.
These findings are ovarian-cohort observations requiring external validation.
evidence:
- reference: PMID:34117242
reference_title: Analysis of the genomic landscape of yolk sac tumors reveals mechanisms of evolution and chemoresistance.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
We identify somatic driver candidates, including significantly mutated
genes KRAS and KIT and copy-number alteration drivers, including deleted
ARID1A and PARK2, and amplified ZNF217, CDKN1B, and KRAS.
explanation: >-
Whole-exome and RNA sequencing directly support the ovarian YST candidate-driver landscape.
- reference: PMID:34117242
reference_title: Analysis of the genomic landscape of yolk sac tumors reveals mechanisms of evolution and chemoresistance.
supports: SUPPORT
evidence_source: IN_VITRO
snippet: >-
We silenced the OVOL2 expression using two independent small interfering
RNAs (siRNAs) (Fig. 7B) and found that, in NOY1, the knockdown of OVOL2
dose- and time-dependently decreased cell viability in the presence of cisplatin.
explanation: >-
The mechanistic link was tested by OVOL2 perturbation in the NOY1 YST cell
line, so this is in-vitro evidence rather than a clinical association.
- name: Mediastinal GCT and Blood-Cancer Shared-Precursor Branching
biological_scale: CELLULAR
description: >-
In the uncommon syndrome of primary mediastinal nonseminomatous germ cell
tumor with an associated hematologic malignancy, genomic phylogenies support
a shared ancestral precursor followed by divergent, parallel evolution of
the germ-cell tumor and blood cancer. This does not establish serial
transformation of a mature YST component into leukemia, and the finding is
scoped to the associated mediastinal syndrome rather than all YST.
evidence:
- reference: PMID:32897884
reference_title: Germ cell tumors and associated hematologic malignancies evolve from a common shared precursor.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Our findings argue that this scenario represents a unique clinical
syndrome, distinct from de novo GCTs or hematologic malignancies, initiated
by an ancestral precursor that gives rise to the parallel evolution of
GCTs and blood cancers in these patients.
explanation: >-
Genomic clonal reconstruction in 15 associated cases supports branching
from a shared precursor rather than settled YST-to-leukemia conversion.
- name: Somatic-Lineage Plasticity to YST Differentiation
biological_scale: CELLULAR
description: >-
YST-like differentiation associated with a non-germ-cell malignancy may
arise from a malignant pluripotent somatic precursor. This is a distinct
histogenetic setting and must not be represented as proof of a migrated
primordial germ cell.
biological_processes:
- preferred_term: abnormal cell-fate commitment
modifier: ABNORMAL
term:
id: GO:0045165
label: cell fate commitment
evidence:
- reference: PMID:22008025
reference_title: Yolk sac tumours revisited. A review of their many faces and names.
supports: SUPPORT
evidence_source: OTHER
snippet: >-
YSTs associated with non-germ cell tumours probably originate from
malignant pluripotent somatic stem cells.
explanation: >-
The review explicitly frames somatic origin as probable, so the node is
kept separate and not treated as a proven universal origin.
downstream:
- target: Primitive Endodermal Differentiation Program
causal_link_type: UNKNOWN
description: >-
A malignant somatic precursor may converge on YST-like primitive
endodermal differentiation, but the proposed lineage route remains distinct
from conventional germ-cell-derived YST and is not settled.
evidence:
- reference: PMID:22008025
reference_title: Yolk sac tumours revisited. A review of their many faces and names.
supports: SUPPORT
evidence_source: OTHER
snippet: >-
YSTs associated with non-germ cell tumours probably originate from
malignant pluripotent somatic stem cells.
explanation: The review supports only a probable somatic route, hence an unknown causal edge.
phenotypes:
- name: Elevated serum alpha-fetoprotein
description: >-
Elevated circulating AFP is the central biochemical phenotype and a
longitudinal readout of AFP-secreting tumor burden. AFP is not independently
specific for YST and must be interpreted with anatomy and pathology. In
infants, physiologically high postnatal AFP requires comparison with
age-adjusted reference data and serial kinetics rather than an adult upper limit.
phenotype_term:
preferred_term: Elevated circulating alpha-fetoprotein concentration
term:
id: HP:0006254
label: Elevated circulating alpha-fetoprotein concentration
reports_on:
- target: AFP Synthesis and Secretion
relationship: READOUT_OF
direction: POSITIVE
endpoint_context: DIAGNOSTIC
interpretation: Serum AFP reports on secretion by the YST component.
evidence:
- reference: PMID:9354734
reference_title: Actual half-life of alpha-fetoprotein as a prognostic tool in pediatric malignant tumors.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
The increased AHL of AFP indicated residual active tumor after surgical resection.
explanation: >-
Serial AFP decay in children with AFP-secreting malignant tumors directly
supports AFP as a residual-tumor readout.
- name: Testicular neoplasm in infancy or early childhood
subtype: Prepubertal testicular YST
description: >-
Pure prepubertal testicular YST occurs in young boys; in a 33-case series,
ages ranged from 5 to 71 months with a mean of 20.7 months.
phenotype_term:
preferred_term: Testicular neoplasm
term:
id: HP:0010788
label: Testicular neoplasm
onset:
onset_category: INFANTILE
evidence:
- reference: PMID:25828390
reference_title: Yolk Sac Tumor of the Testis in Infants and Children. A Clinicopathologic Analysis of 33 Cases.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
We report 33 pure yolk sac tumors of the testis from boys 5 to 71 months
of age (mean 20.7 mo) diagnosed from 1918 to 2014.
explanation: A pure-YST series directly supports the early-childhood testicular context.
- name: Ovarian mass
subtype: Ovarian YST
description: >-
A reported mixed ovarian germ cell tumor containing YST presented as a
large abdominopelvic mass. This single case does not establish a usual
presentation for pure ovarian YST.
phenotype_term:
preferred_term: Ovarian neoplasm
term:
id: HP:0100615
label: Ovarian neoplasm
evidence:
- reference: PMID:40037273
reference_title: "Acute abdominopelvic pain and distension in a 21-year-old woman revealing a mixed germ cell tumor: A case report."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
We present the case of a 21-year-old female who was admitted urgently due
to a large abdominopelvic mass.
explanation: The mixed ovarian GCT case documents one mass presentation without establishing frequency.
- name: Abnormal vaginal bleeding
subtype: Pediatric extragonadal YST
description: >-
A reported one-year-old girl with vaginal YST presented with prolonged
vaginal bleeding and urinary retention. This case does not establish a
characteristic presentation frequency for vaginal YST.
phenotype_term:
preferred_term: Abnormal vaginal bleeding
term:
id: HP:0034263
label: Abnormal vaginal bleeding
evidence:
- reference: PMID:40818404
reference_title: "Pediatric vaginal yolk sac tumor: A rare case report and diagnostic challenges."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
We present a case of vaginal YST involving a one-year-old girl who
presented with prolonged vaginal bleeding and urinary retention.
explanation: The pediatric vaginal YST case directly supports the site-specific symptom.
- name: Mediastinal mass
subtype: Mediastinal postpubertal YST
description: >-
A mediastinal YST component occurs within a primary mediastinal
nonseminomatous GCT mass, predominantly in adolescent or young adult males;
this phenotype does not imply that the entire mass is pure YST.
phenotype_term:
preferred_term: Mediastinal mass
term:
id: HP:0033823
label: Mediastinal mass
evidence:
- reference: PMID:25395492
reference_title: "The yolk sac tumor: reflections on a remarkable neoplasm and two of the many intrigued by it-Gunnar Teilum and Aleksander Talerman-and the bond it formed between them."
supports: SUPPORT
evidence_source: OTHER
snippet: mediastinal forms are mostly restricted to young adult males
explanation: The review supports the age/site pattern while the description preserves mixed-tumor scope.
histopathology:
- name: Reticular-Microcystic Pattern
description: >-
The most common pattern is a reticular or microcystic network. YST is
histologically heterogeneous, so absence of this pattern does not exclude it.
finding_term:
preferred_term: reticular-microcystic growth pattern
term:
id: NCIT:C157706
label: Microcystic Growth Pattern
evidence:
- reference: PMID:25828390
reference_title: Yolk Sac Tumor of the Testis in Infants and Children. A Clinicopathologic Analysis of 33 Cases.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
The commonest pattern was reticular-microcystic, but macrocystic,
papillary, endodermal sinus (Schiller-Duval bodies), labyrinthine,
myxomatous, glandular, and solid patterns were also observed.
explanation: A pure pediatric testicular YST series documents both the dominant and variant patterns.
- name: Schiller-Duval Bodies
description: >-
Endodermal-sinus structures are characteristic when present but are only
one pattern within the broader morphologic spectrum; diagnosis should not
require them in every tumor.
finding_term:
preferred_term: Schiller-Duval body
term:
id: NCIT:C54124
label: Schiller-Duval Body
diagnostic: true
evidence:
- reference: PMID:25828390
reference_title: Yolk Sac Tumor of the Testis in Infants and Children. A Clinicopathologic Analysis of 33 Cases.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
The commonest pattern was reticular-microcystic, but macrocystic,
papillary, endodermal sinus (Schiller-Duval bodies), labyrinthine,
myxomatous, glandular, and solid patterns were also observed.
explanation: The cohort places Schiller-Duval bodies within, rather than above, the full pattern spectrum.
- name: SALL4-Positive OCT4-Negative Immunophenotype
description: >-
Diffuse nuclear SALL4 is highly sensitive in extragonadal and pediatric YST.
In the cited extragonadal series, OCT4 negativity separated YST from
OCT4-positive germ cell components; AFP and glypican-3 were less diffuse
than SALL4 in many tumors.
diagnostic: true
evidence:
- reference: PMID:19574883
reference_title: >-
Diagnostic utility of SALL4 in extragonadal yolk sac tumors: an
immunohistochemical study of 59 cases with comparison to placental-like
alkaline phosphatase, alpha-fetoprotein, and glypican-3.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: All 59 YSTs were negative for OCT4.
explanation: The extragonadal series directly supports OCT4 negativity.
- reference: PMID:19574883
reference_title: >-
Diagnostic utility of SALL4 in extragonadal yolk sac tumors: an
immunohistochemical study of 59 cases with comparison to placental-like
alkaline phosphatase, alpha-fetoprotein, and glypican-3.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Strong SALL4 staining was seen in all 59 YSTs (in more than 90% tumor cells
in 54 and 70% to 85% tumor cells in 5 YSTs).
explanation: The series establishes diffuse SALL4 sensitivity in extragonadal YST.
biochemical:
- name: Serum Alpha-Fetoprotein
notes: >-
Serial serum AFP decay after resection can indicate residual active tumor or
preclinical recurrence in AFP-secreting pediatric tumors; AFP is not a
stand-alone histologic diagnosis. Neonatal and infant
values must be interpreted against age-adjusted reference data because
physiologic AFP remains above adult levels for months after birth.
biomarker_term:
preferred_term: Alpha-Fetoprotein
term:
id: NCIT:C16278
label: Alpha-Fetoprotein
readouts:
- target: AFP Synthesis and Secretion
relationship: READOUT_OF
direction: POSITIVE
endpoint_context: DIAGNOSTIC
evidence:
- reference: PMID:9354734
reference_title: Actual half-life of alpha-fetoprotein as a prognostic tool in pediatric malignant tumors.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
In group 1, which had complete resection and no recurrence during
follow-up (n = 13), the AHL of AFP was 4.0 +/- 0.9 days.
explanation: This supplies the observed post-resection AFP decay in children without recurrence.
- reference: PMID:9354734
reference_title: Actual half-life of alpha-fetoprotein as a prognostic tool in pediatric malignant tumors.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
In group 2, which had incomplete resection or recurrence during follow-up
(n = 5), the AHL of AFP was 24.8 +/- 20 days, significantly longer than
that of group 1 (P = 0.0026).
explanation: This supports delayed AFP clearance as a residual/recurrent-tumor signal.
evidence:
- reference: PMID:6163129
reference_title: Serum alpha fetoprotein (AFP) levels in normal infants.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
We found that it was not until 8 months of age that the normal AFP level
in infants approached adult level.
explanation: >-
Normal-infant longitudinal data establish why an adult AFP cutoff is
inappropriate in early infancy.
- name: SALL4 Expression
notes: >-
SALL4 is a sensitive tissue biomarker but is not specific to YST; it must be
interpreted in a morphology- and panel-based diagnosis.
biomarker_term:
preferred_term: Sal-Like Protein 4
term:
id: NCIT:C112908
label: Sal-Like Protein 4
evidence:
- reference: PMID:32222813
reference_title: SALL4 is a useful marker for pediatric yolk sac tumors.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
In contrast to AFP and glypican-3, SALL4 staining in more than 90% of the
tumor cells was seen in all 22 pediatric YSTs (100% sensitivity)
(P < 0.001 for both SALL4 vs. AFP and SALL4 vs. glypican-3).
explanation: A pediatric YST series directly supports high sensitivity and diffuse staining.
- name: FOXA2 Nuclear Expression
subtype: Postpubertal testicular YST
notes: >-
Nuclear FOXA2 immunohistochemistry is curated here only for postpubertal-type
testicular YST, the population tested in this 24-case series; it is not
generalized to prepubertal, ovarian, extragonadal, CNS, or somatically
derived YST. Mature glands in postpubertal-type teratoma are a diagnostic
pitfall, so FOXA2 remains part of a morphology- and panel-based diagnosis.
biomarker_term:
preferred_term: Hepatocyte Nuclear Factor 3-Beta
term:
id: NCIT:C73454
label: Hepatocyte Nuclear Factor 3-Beta
specificity: >-
Highly sensitive and specific within the tested postpubertal-type testicular
YST cohort, with superior performance to GPC3 and AFP in difficult patterns;
mature teratomatous glands can also stain.
evidence:
- reference: PMID:37317674
reference_title: FoxA2 is a reliable marker for the diagnosis of yolk sac tumour postpubertal-type.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
FoxA2 was positive in all YSTpt (24 of 24) and all but one (23 of 24)
exhibited 2+/3+ stain
explanation: >-
The postpubertal-type testicular cohort directly establishes universal
FOXA2 positivity and moderate-to-diffuse staining in 23 of 24 tumors.
- reference: PMID:37317674
reference_title: FoxA2 is a reliable marker for the diagnosis of yolk sac tumour postpubertal-type.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
FoxA2 is a highly sensitive and specific biomarker that supports the
diagnosis of YSTpt. FoxA2 is superior to GPC3 and AFP, especially in rare
and difficult-to-diagnose histological patterns of YSTpt, but mature glands
of Tpt could represent a potential diagnostic pitfall.
explanation: >-
The authors' conclusion supports the comparative diagnostic role while
preserving the tested postpubertal-type scope and teratoma pitfall.
- name: Glypican-3 Expression
notes: >-
Glypican-3 is frequently positive but variable in extent and is interpreted
as part of an immunohistochemical panel.
biomarker_term:
preferred_term: Glypican-3
term:
id: NCIT:C88175
label: Glypican-3
evidence:
- reference: PMID:19574883
reference_title: >-
Diagnostic utility of SALL4 in extragonadal yolk sac tumors: an
immunohistochemical study of 59 cases with comparison to placental-like
alkaline phosphatase, alpha-fetoprotein, and glypican-3.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Although all 59 YSTs showed positive glypican-3 staining, 18 (30%) showed
staining in less than 30% tumor cells, and additional 10 (17%) showed
staining in between 30% and 60% tumor cells.
explanation: This establishes frequent but variably extensive glypican-3 staining.
genetic:
- name: Pediatric recurrent chromosomal imbalances
association: >-
Recurrent childhood malignant-GCT pattern of distal 1p loss, 1q/20q gain,
and 4q/6q deletion in a mixed-site, mixed-histology cohort; not a
prepubertal-testicular-YST-specific or obligatory driver set
variant_origin: SOMATIC
evidence:
- reference: PMID:11528555
reference_title: Genetic analysis of childhood germ cell tumors with comparative genomic hybridization.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Irrespective of the primary site, childhood GCTs show chromosomal
imbalances of chromosome 1 (loss of distal 1p, gain of 1q), deletion of 4q
and 6q as well as gain of 20q at a high frequency.
explanation: The evidence is pediatric malignant-GCT-level rather than isolated pure-YST sequencing.
- name: Isochromosome 12p or other 12p gain
subtype: Postpubertal testicular YST
association: Shared clonal hallmark of GCNIS-related/type II testicular germ cell tumors
variant_origin: SOMATIC
evidence:
- reference: PMID:41384700
reference_title: "Molecular pathology of testicular germ cell tumours: an update for practicing pathologists."
supports: SUPPORT
evidence_source: OTHER
snippet: >-
A common molecular alteration in type II TGCTs is the presence of an
isochromosome 12p or gain of 12p material.
explanation: The claim is explicitly restricted to the postpubertal/type II context.
- name: KRAS
subtype: Ovarian YST
gene_term:
preferred_term: KRAS
term:
id: hgnc:6407
label: KRAS
association: Candidate recurrent somatic driver mutation and copy-number amplification in ovarian YST
relationship_type: SOMATIC_DRIVER
variant_origin: SOMATIC
evidence:
- reference: PMID:34117242
reference_title: Analysis of the genomic landscape of yolk sac tumors reveals mechanisms of evolution and chemoresistance.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
We identify somatic driver candidates, including significantly mutated
genes KRAS and KIT and copy-number alteration drivers, including deleted
ARID1A and PARK2, and amplified ZNF217, CDKN1B, and KRAS.
explanation: The ovarian cohort identifies KRAS through both mutation and amplification analyses.
- name: KIT
subtype: Ovarian YST
gene_term:
preferred_term: KIT
term:
id: hgnc:6342
label: KIT
association: Candidate recurrent somatic driver mutation in ovarian YST
relationship_type: SOMATIC_DRIVER
variant_origin: SOMATIC
evidence:
- reference: PMID:34117242
reference_title: Analysis of the genomic landscape of yolk sac tumors reveals mechanisms of evolution and chemoresistance.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
We identify somatic driver candidates, including significantly mutated
genes KRAS and KIT and copy-number alteration drivers, including deleted
ARID1A and PARK2, and amplified ZNF217, CDKN1B, and KRAS.
explanation: The ovarian cohort identifies KIT as a significantly mutated candidate driver.
- name: TP53
subtype: Ovarian YST
gene_term:
preferred_term: TP53
term:
id: hgnc:11998
label: TP53
association: Infrequently mutated in the studied ovarian YST cohort; not a universal absence
variant_origin: SOMATIC
evidence:
- reference: PMID:34117242
reference_title: Analysis of the genomic landscape of yolk sac tumors reveals mechanisms of evolution and chemoresistance.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
YSTs have very infrequent TP53 mutations, whereas the tumors from patients
with abnormal gonadal development contain both KRAS and TP53 mutations.
explanation: The source supports rarity with a defined gonadal-development exception.
- name: Klinefelter syndrome (47,XXY) association
association: >-
Strongly increased incidence of extragonadal germ cell tumor, particularly
mediastinal disease, in a Klinefelter syndrome cohort; this is a
mediastinal-GCT association rather than a YST-component-specific estimate
variant_origin: GERMLINE
evidence:
- reference: PMID:41789737
reference_title: Incidence of Gonadal and Extragonadal Germ Cell Tumours in Patients With Klinefelter Syndrome.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
For EGCT, the crude age-standardised incidence ratio was 83.0 (95% CI,
2.1-460.5).
explanation: >-
The cohort quantifies the Klinefelter-extragonadal-GCT association, while
the wide interval and one mediastinal event require cautious interpretation.
prevalence:
- population: Children and adolescents in the United States SEER registries, 2000-2018
measure_type: UNKNOWN
prevalence_class: UNKNOWN
notes: >-
A population-based study identified 520 pediatric YST cases in SEER over 19
diagnosis years. This is a registry case count, not a prevalence or
incidence denominator; no population rate is inferred here.
evidence:
- reference: PMID:37747514
reference_title: >-
Clinical characteristics and prognostic models of gonadal and extra-gonadal
yolk sac tumors: a population-based analysis in children and adolescents.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
A total of 520 YST patients were identified.
explanation: This is retained as an occurrence anchor without manufacturing a rate.
progression:
- phase: Pediatric population-based survival
age_range: Children and adolescents
notes: >-
In SEER 2000-2018, pediatric YST had 92.2% 3-year and 90.3% 5-year overall
survival; older age and extragonadal site were adverse in that analysis.
evidence:
- reference: PMID:37747514
reference_title: >-
Clinical characteristics and prognostic models of gonadal and extra-gonadal
yolk sac tumors: a population-based analysis in children and adolescents.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Overall survival rates for all patients were 92.2% at 3-year and 90.3% at
5-year, respectively.
explanation: The population-based cohort provides YST-specific overall survival.
- reference: PMID:37747514
reference_title: >-
Clinical characteristics and prognostic models of gonadal and extra-gonadal
yolk sac tumors: a population-based analysis in children and adolescents.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Furthermore, patients with extra-gonadal YST have a lower survival rate
than those with gonadal YST.
explanation: This supports site-stratified prognosis rather than one uniform outcome.
- phase: Platinum-treated ovarian YST outcome
age_range: Children, adolescents, and adults aged 0-38 years
notes: >-
A pooled international trial dataset included pure YST, mixed tumors with a
YST component, and AFP-defined putative YST. The combined 5-year EFS was 91%
and OS 96%; this is not a pure-YST-only estimate.
evidence:
- reference: PMID:29194189
reference_title: Ovarian Yolk Sac Tumors; Does Age Matter?
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
The overall 5-year event-free survival and overall survival was 91% (95%
confidence interval, 87%-94%) and 96% (92%-98%), respectively.
explanation: The pooled ovarian YST dataset directly reports the combined outcomes.
- reference: PMID:29194189
reference_title: Ovarian Yolk Sac Tumors; Does Age Matter?
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Histology was pure, mixed, and putative in 129, 56, and 66 cases, respectively.
explanation: This makes the component mixture behind the outcome estimate explicit.
- phase: Stage I ovarian surveillance and early relapse
age_range: Girls aged 0-16 years
notes: >-
Surgery followed by surveillance spared chemotherapy in about half of a
small pediatric stage I malignant ovarian GCT cohort dominated by YST, but
recurrences were early and AFP-positive; salvage preserved overall survival.
evidence:
- reference: PMID:24395845
reference_title: >-
Surveillance after initial surgery for pediatric and adolescent girls
with stage I ovarian germ cell tumors: report from the Children's Oncology Group.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
After a median follow-up of 42 months, 12 patients had evidence of
persistent or recurrent disease (4-year EFS, 52%; 95% CI, 31% to 69%).
explanation: The prospective COG study quantifies recurrence under stage I surveillance.
- reference: PMID:24395845
reference_title: >-
Surveillance after initial surgery for pediatric and adolescent girls
with stage I ovarian germ cell tumors: report from the Children's Oncology Group.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Eleven of 12 patients experiencing relapse received successful salvage
chemotherapy (4-year OS, 96%; 95% CI, 74% to 99%).
explanation: This supports the high salvage-supported overall survival.
- phase: Stage I pediatric testicular outcome
age_range: Pediatric and adolescent
notes: >-
In pooled prospective trials, all evaluable stage I tumors contained YST
elements; no deaths occurred, while age at least 12 years and higher pT
stage predicted events. This is not a pure prepubertal-YST-only cohort.
evidence:
- reference: PMID:35606324
reference_title: >-
Clinicopathologic predictors of outcomes in children with stage I
testicular germ cell tumors: A pooled post hoc analysis of trials from
the Children's Oncology Group.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Among patients with evaluable histopathology, yolk sac tumor elements
were present in all patients and lymphovascular invasion in 51% of patients.
explanation: This defines the YST-containing nature of the stage I cohort.
- reference: PMID:35606324
reference_title: >-
Clinicopathologic predictors of outcomes in children with stage I
testicular germ cell tumors: A pooled post hoc analysis of trials from
the Children's Oncology Group.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Over a median follow-up of 56 months, no patients died, and 25 patients
(24%) experienced an event (median event-free survival not reached).
explanation: This separates excellent survival from nonzero relapse/event risk.
- phase: Mediastinal GCT-associated hematologic malignancy
age_range: Patients with primary mediastinal nonseminomatous germ cell tumors
notes: >-
In an international retrospective series, 17 of 287 patients with primary
mediastinal nonseminomatous germ cell tumors developed a hematologic
disorder. The median onset was 6 months and median survival after the blood
cancer diagnosis was 5 months. This severe mediastinal-GCT syndrome is not
automatically attributable to a YST component in every mixed tumor.
evidence:
- reference: PMID:10620634
reference_title: Hematologic disorders associated with primary mediastinal nonseminomatous germ cell tumors.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
A hematologic disorder was observed in 17 patients with germ cell tumors.
explanation: >-
The cohort makes the hematologic risk substantive and confines it to
primary mediastinal nonseminomatous GCT rather than all YST.
- reference: PMID:10620634
reference_title: Hematologic disorders associated with primary mediastinal nonseminomatous germ cell tumors.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
The median time to onset of hematologic neoplasia was 6 months (range,
0-47 months), and the median survival after diagnosis of the hematologic
disorder was 5 months (range, 0-16 months).
explanation: The series directly quantifies the early onset and poor outcome.
diagnosis:
- name: Integrated Histopathology and Immunohistochemistry
description: >-
Diagnose YST by architecture and cytology integrated with an antibody panel.
SALL4 was strong and diffuse in the cited 59-case extragonadal series,
whereas AFP and glypican-3 were often focal or variable. SALL4 is also
expressed by other primitive germ cell
tumors; OCT4 negativity helps distinguish YST from germinoma/dysgerminoma
and embryonal carcinoma. No single stain substitutes for morphology.
diagnosis_term:
preferred_term: Histopathologic Examination
term:
id: NCIT:C18190
label: Histopathologic Examination
evidence:
- reference: PMID:19574883
reference_title: >-
Diagnostic utility of SALL4 in extragonadal yolk sac tumors: an
immunohistochemical study of 59 cases with comparison to placental-like
alkaline phosphatase, alpha-fetoprotein, and glypican-3.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Our results indicate that SALL4 is a novel sensitive (100% sensitivity)
diagnostic marker for extragonadal YSTs.
explanation: A large extragonadal series supports SALL4 as a sensitive panel component.
- reference: PMID:19574883
reference_title: >-
Diagnostic utility of SALL4 in extragonadal yolk sac tumors: an
immunohistochemical study of 59 cases with comparison to placental-like
alkaline phosphatase, alpha-fetoprotein, and glypican-3.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Positive AFP staining was seen in the vast majority of YSTs (56 of 59 or
95%); however, 32 (54%) YSTs showed staining in less than 30% tumor cells.
Although all 59 YSTs showed positive glypican-3 staining, 18 (30%) showed
staining in less than 30% tumor cells, and additional 10 (17%) showed
staining in between 30% and 60% tumor cells.
explanation: >-
The same series directly shows why AFP and glypican-3 should not be called
uniformly diffuse.
- name: Serum AFP Measurement and Kinetic Follow-up
markers: AFP
description: >-
Follow serum AFP serially after resection of an AFP-secreting tumor.
Delayed clearance supports residual active tumor and AFP half-life may
detect preclinical recurrence. In infants, compare AFP with age-adjusted
physiologic ranges before attributing an elevation to tumor;
interpretation remains contextual rather than diagnostic alone.
diagnosis_term:
preferred_term: Alpha-fetoprotein Measurement
term:
id: NCIT:C74732
label: Alpha-fetoprotein Measurement
evidence:
- reference: PMID:9354734
reference_title: Actual half-life of alpha-fetoprotein as a prognostic tool in pediatric malignant tumors.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
The increased AHL of AFP indicated residual active tumor after surgical resection.
explanation: Serial AFP kinetics directly report residual active tumor in the pediatric study.
- reference: PMID:9354734
reference_title: Actual half-life of alpha-fetoprotein as a prognostic tool in pediatric malignant tumors.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
The AHL of AFP may be more sensitive than serial monitoring of AFP in
detecting preclinical recurrence after surgical resection of AFP-secreting tumors.
explanation: The pediatric study explicitly supports the post-resection recurrence use.
- reference: PMID:6163129
reference_title: Serum alpha fetoprotein (AFP) levels in normal infants.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
We found that it was not until 8 months of age that the normal AFP level
in infants approached adult level.
explanation: >-
Normal infant data require age-adjusted rather than adult AFP thresholds.
- name: Site-Specific Staging and Risk Classification
description: >-
Stage and risk-classify the complete germ cell tumor context rather than the
YST component in isolation. Advanced postpubertal testicular germ cell tumors
use IGCCCG risk classification, primary mediastinal nonseminoma is assigned
to the IGCCCG poor-prognosis group, and the cited ovarian YST cohorts use
FIGO stage. The pediatric evidence here is limited to stage I ovarian
malignant germ cell tumors and does not establish a universal pediatric
extracranial or CNS YST staging convention.
diagnosis_term:
preferred_term: staging procedure
term:
id: NCIT:C18020
label: Diagnostic Procedure
evidence:
- reference: PMID:18302061
reference_title: Influence of tumor site and histology on long-term survival in 193 children with extracranial germ cell tumors.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Although germ cell tumors (GCT) supposedly share the same cell type of
origin, their clinical course differs considerably depending on tumor site and histology.
explanation: The pediatric cohort supports preserving site and histology in clinical interpretation.
- reference: PMID:38958901
reference_title: SEOM-GG clinical guidelines for the management of germ-cell testicular cancer (2023).
supports: SUPPORT
evidence_source: OTHER
snippet: >-
Patients with persistent markers after orchiectomy or advanced disease at
diagnosis should be staged and classified according to the IGCCCG
prognostic classification.
explanation: This supports IGCCCG risk classification in advanced postpubertal testicular disease.
- reference: PMID:35554637
reference_title: How to classify, diagnose, treat and follow-up extragonadal germ cell tumors? A systematic review of available evidence.
supports: SUPPORT
evidence_source: OTHER
snippet: >-
EGCT patients are classified according to the IGCCCG classification.
Consecutively, all mediastinal non-seminomatous EGCT patients belong to
the "poor prognosis" group.
explanation: >-
The systematic review supplies the mediastinal nonseminomatous risk
context; it is not a YST-component-specific stage.
- reference: PMID:29194189
reference_title: Ovarian Yolk Sac Tumors. Does Age Matter?
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Any patient with an O-YST that was International Federation of Gynecology
and Obstetrics stage IC or higher and treated with a platinum-based
chemotherapy was eligible.
explanation: >-
The pooled ovarian trials explicitly use FIGO stage while retaining pure,
mixed, and putative histology strata.
- reference: PMID:24395845
reference_title: "Surveillance after initial surgery for pediatric and adolescent girls with stage I ovarian germ cell tumors: report from the Children's Oncology Group."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Between November 2003 and July 2011, girls age 0 to 16 years with stage I
MOGCT were enrolled onto Children's Oncology Group study AGCT0132.
explanation: >-
This supports the stage I pediatric ovarian context only; it does not
establish staging conventions for other pediatric extracranial sites.
differential_diagnoses:
- name: Juvenile granulosa cell tumor of the testis
description: >-
In an infant with a testicular tumor, juvenile granulosa cell tumor overlaps
in age and some morphology but is a sex-cord stromal tumor. Architecture and
an appropriate immunohistochemical panel distinguish it from YST.
distinguishing_features:
- The cited pure testicular YST series notes morphologic overlap with juvenile granulosa cell tumor.
- In that series, juvenile granulosa cell tumor occurred at a slightly younger age and had distinctive features.
evidence:
- reference: PMID:25828390
reference_title: Yolk Sac Tumor of the Testis in Infants and Children. A Clinicopathologic Analysis of 33 Cases.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
It is crucial that this tumor be distinguished from the juvenile granulosa
cell tumor, which occurs at a slightly younger age and has distinctive
features, although there may be some morphologic overlap.
explanation: The pure pediatric testicular YST series directly names the differential.
- name: Mature teratoma
description: >-
Pediatric teratoma can occur in the same age/site spectrum. Diffuse SALL4
staining supports YST over mature teratoma when morphology is challenging.
distinguishing_features:
- Diffuse nuclear SALL4 in the malignant primitive component favors YST.
- Mature somatic tissues without a malignant YST component favor mature teratoma.
evidence:
- reference: PMID:32222813
reference_title: SALL4 is a useful marker for pediatric yolk sac tumors.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
SALL4 is a sensitive marker for pediatric YSTs and it can be used to
distinguish them from mature teratomas.
explanation: The 22-YST/10-teratoma comparison directly supports this distinction.
- name: Ovarian clear cell carcinoma
description: >-
Ovarian YST and clear cell carcinoma can overlap morphologically. Diffuse
nuclear SALL4 favors YST in this site, while an integrated epithelial-marker
profile and morphology support clear cell carcinoma; SALL4 is not a
universal germ-cell-subtype discriminator.
distinguishing_features:
- Diffuse SALL4 with compatible endodermal-sinus or reticular morphology favors YST.
- In the cited comparison, CK7 and EMA were positive in all 45 clear cell carcinomas but only focally positive in 3 and 4 YSTs, respectively.
evidence:
- reference: PMID:19295406
reference_title: SALL4 is a novel sensitive and specific marker of ovarian primitive germ cell tumors and is particularly useful in distinguishing yolk sac tumor from clear cell carcinoma.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
SALL4 is particularly useful in distinguishing YST from CCC and better
than AFP, glypican-3, CK7, and EMA.
explanation: The ovarian immunohistochemical comparison directly addresses this differential.
- reference: PMID:19295406
reference_title: SALL4 is a novel sensitive and specific marker of ovarian primitive germ cell tumors and is particularly useful in distinguishing yolk sac tumor from clear cell carcinoma.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Three (10%) and 4 (14%) YSTs show focal (<2% tumor cells) CK7 and EMA
staining, respectively. CK7 and EMA are positive in all 45 CCCs but 3
(7%) and 1 (2%) cases show staining in less than 30% tumor cells, respectively.
explanation: The ovarian series supplies the exact CK7 and EMA comparison.
- name: CNS germinoma or embryonal carcinoma component
description: >-
In primary CNS germ cell tumors, germinoma and embryonal carcinoma can also
express diffuse SALL4. Strong OCT4 supports those CNS components, whereas
other germ cell tumors in the cited CNS series were OCT4-negative;
morphology and a full panel remain required.
distinguishing_features:
- In a primary CNS germ cell tumor, strong OCT4 with compatible morphology favors germinoma or embryonal carcinoma.
- In that CNS differential, OCT4 negativity does not identify YST without compatible morphology and a full panel.
evidence:
- reference: PMID:19820689
reference_title: "Diagnostic utility of SALL4 in primary germ cell tumors of the central nervous system: a study of 77 cases."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
All germinomas and embryonal carcinomas showed strong OCT4 staining (4+
in all except 1 germinoma with 3+), whereas other germ cell tumors were negative.
explanation: >-
The CNS germ-cell-tumor series shows why SALL4 alone cannot separate these
primitive components and supports OCT4 as a discriminator.
- name: Non-germ-cell carcinoma with YST-like morphology or differentiation
description: >-
Endometrial, gastric, lung, and other somatic carcinomas may show endodermal
morphology or a somatically derived YST component. Patient age, anatomic
setting, associated conventional carcinoma, molecular profile, and the full
immunophenotypic panel determine whether this is a germ-cell-derived YST.
distinguishing_features:
- The cited review states that endodermal somatic differentiation may reproduce pulmonary, intestinal, and hepatic tissues.
- It also reports morphologic identity with some embryonal-type endodermal gastric and lung carcinomas.
evidence:
- reference: PMID:22008025
reference_title: Yolk sac tumours revisited. A review of their many faces and names.
supports: SUPPORT
evidence_source: OTHER
snippet: >-
Endodermal somatic differentiation reproduces pulmonary, intestinal and
hepatic tissues and are identical with some, embryonal-type endodermal,
gastric and lung carcinomas, which are indistinguishable from YSTs.
explanation: The pathology review directly documents the morphologic overlap.
treatments:
- name: Testicular Inguinal Orchiectomy
description: >-
Radical inguinal orchiectomy establishes diagnosis and local control for a
testicular tumor containing YST. Subsequent surveillance, staging, and
systemic therapy differ between prepubertal-type pure YST and postpubertal
GCNIS-related pure or mixed nonseminomatous tumors.
therapeutic_modality: SURGERY
treatment_term:
preferred_term: orchiectomy
term:
id: NCIT:C15288
label: Orchiectomy
evidence:
- reference: PMID:38958901
reference_title: SEOM-GG clinical guidelines for the management of germ-cell testicular cancer (2023).
supports: SUPPORT
evidence_source: OTHER
snippet: >-
Inguinal orchiectomy is the main diagnostic procedure, and is also
curative for most localized tumors, while patients with unfavorable risk
factors for recurrence, or those who are unable or unwilling to undergo
close follow-up, may require adjuvant treatment.
explanation: The guideline supports the testicular operation without generalizing follow-up across ages and risks.
- name: Ovarian Fertility-Sparing Surgery
description: >-
Unilateral salpingo-oophorectomy with limited, site-appropriate staging is
preferred when feasible for adolescent and young-adult ovarian malignant
germ cell tumors containing YST. Operative extent depends on stage, tumor
burden, fertility goals, and whether the lesion is pure YST, a mixed germ
cell tumor, or YST differentiation in a somatic epithelial neoplasm.
therapeutic_modality: SURGERY
treatment_term:
preferred_term: unilateral salpingo-oophorectomy
term:
id: NCIT:C94469
label: Unilateral Salpingo-oophorectomy
evidence:
- reference: PMID:41001186
reference_title: Updates in the Management of Malignant Ovarian Germ Cell Tumors.
supports: SUPPORT
evidence_source: OTHER
snippet: >-
Fertility-sparing surgery, including unilateral salpingo-oophorectomy with
minimal staging, is recommended for adolescent and young adult patients.
explanation: The review supports the ovarian site-specific fertility-preserving approach.
- name: Postpubertal and Adult Risk-Adapted BEP Chemotherapy
description: >-
BEP is a cisplatin-based backbone for postpubertal/adult malignant germ cell
tumors containing YST, with cycles and alternatives selected by site,
anatomic stage, marker kinetics, and IGCCCG group. It also has an ovarian
role, but this record does not assign adult BEP to every pediatric or CNS setting.
therapeutic_modality: SMALL_MOLECULE
regimen_term:
preferred_term: BEP Regimen
term:
id: NCIT:C63488
label: BEP Regimen
treatment_term:
preferred_term: chemotherapy
term:
id: NCIT:C15632
label: Chemotherapy
therapeutic_agent:
- preferred_term: bleomycin
term:
id: CHEBI:22907
label: bleomycin
- preferred_term: etoposide
term:
id: CHEBI:4911
label: etoposide
- preferred_term: cisplatin
term:
id: CHEBI:27899
label: cisplatin
evidence:
- reference: PMID:38958901
reference_title: SEOM-GG clinical guidelines for the management of germ-cell testicular cancer (2023).
supports: SUPPORT
evidence_source: OTHER
snippet: >-
Patients with persistent markers after orchiectomy or advanced disease at
diagnosis should be staged and classified according to the IGCCCG
prognostic classification. BEP is the most recommended chemotherapy, but
other schedules such as EP or VIP may be used to avoid bleomycin in some patients.
explanation: The current guideline ties postpubertal testicular systemic treatment to IGCCCG context.
- reference: PMID:41001186
reference_title: Updates in the Management of Malignant Ovarian Germ Cell Tumors.
supports: SUPPORT
evidence_source: OTHER
snippet: The bleomycin/etoposide/cisplatin regimen remains the first-line therapy.
explanation: The ovarian malignant-germ-cell-tumor review explicitly supports an ovarian BEP role.
- name: Pediatric Compressed PEB Chemotherapy
description: >-
Selected pediatric protocols use cisplatin, etoposide, and bleomycin (PEB),
including compressed three-cycle salvage for residual or recurrent stage I
ovarian malignant germ cell tumors. This protocol evidence includes tumors
containing YST and should not be extrapolated to every pediatric site or stage.
therapeutic_modality: SMALL_MOLECULE
treatment_term:
preferred_term: chemotherapy
term:
id: NCIT:C15632
label: Chemotherapy
therapeutic_agent:
- preferred_term: cisplatin
term:
id: CHEBI:27899
label: cisplatin
- preferred_term: etoposide
term:
id: CHEBI:4911
label: etoposide
- preferred_term: bleomycin
term:
id: CHEBI:22907
label: bleomycin
evidence:
- reference: PMID:24395845
reference_title: "Surveillance after initial surgery for pediatric and adolescent girls with stage I ovarian germ cell tumors: report from the Children's Oncology Group."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
In those with residual or recurrent disease, chemotherapy with compressed
PEB (cisplatin, etoposide, and bleomycin) was initiated every 3 weeks for three cycles.
explanation: This directly supports the context-specific pediatric compressed-PEB record.
- name: Pediatric JEB Chemotherapy
description: >-
Carboplatin, etoposide, and bleomycin (JEB) is a pediatric extracranial-GCT
protocol option supported by a UK study of patients aged 0-16 years that
included 107 YSTs. Its carboplatin backbone is specific to protocols and
jurisdictions, not interchangeable with adult BEP or CNS regimens by default.
therapeutic_modality: SMALL_MOLECULE
treatment_term:
preferred_term: chemotherapy
term:
id: NCIT:C15632
label: Chemotherapy
therapeutic_agent:
- preferred_term: carboplatin
term:
id: CHEBI:31355
label: carboplatin
- preferred_term: etoposide
term:
id: CHEBI:4911
label: etoposide
- preferred_term: bleomycin
term:
id: CHEBI:22907
label: bleomycin
evidence:
- reference: PMID:11078494
reference_title: "The United Kingdom Children's Cancer Study Group's second germ cell tumor study: carboplatin, etoposide, and bleomycin are effective treatment for children with malignant extracranial germ cell tumors, with acceptable toxicity."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
The remaining 184 patients had germinoma (n = 20), malignant teratoma (n =
55), embryonal carcinoma (n = 1), yolk sac tumor (n = 107), or
choriocarcinoma (n = 1). Forty-seven patients were treated with surgery
alone, and 137 patients received JEB.
explanation: The pediatric study directly documents the histologic mixture and JEB exposure.
- reference: PMID:41525035
reference_title: Establishment and characterization of a testicular yolk sac tumor PDX model.
supports: SUPPORT
evidence_source: MODEL_ORGANISM
snippet: >-
JEB treatment induced significant tumor regression without causing
clinically relevant body weight loss.
explanation: >-
The testicular YST xenograft provides preclinical response evidence; it
does not substitute for the pediatric clinical protocol evidence above.
- name: Primary Mediastinal Poor-Risk Cisplatin-Based Therapy
description: >-
Primary mediastinal nonseminomatous GCT is an IGCCCG poor-risk setting. The
cited review recommends individualized dose-intensified or high-dose upfront
chemotherapy and expert-center referral. This
whole-tumor risk category is not evidence that every mediastinal YST
component independently has the same prognosis.
therapeutic_modality: SMALL_MOLECULE
treatment_term:
preferred_term: chemotherapy
term:
id: NCIT:C15632
label: Chemotherapy
evidence:
- reference: PMID:35554637
reference_title: How to classify, diagnose, treat and follow-up extragonadal germ cell tumors? A systematic review of available evidence.
supports: SUPPORT
evidence_source: OTHER
snippet: >-
however, due to their very poor prognosis patients with non-seminomatous
mediastinal GCT should receive a dose-intensified or high-dose chemotherapy
approach upfront on an individual basis and should thus be referred to expert centers
explanation: The systematic review explicitly supports individualized intensified therapy and expert-center referral.
- name: Post-Chemotherapy Mediastinal Residual-Mass Resection
description: >-
Resect the residual mediastinal mass after platinum-based chemotherapy for
primary mediastinal nonseminomatous GCT when technically feasible, using an
experienced high-volume multidisciplinary center. Management follows the
residual whole tumor, which may be mixed, rather than a YST component alone.
therapeutic_modality: SURGERY
treatment_term:
preferred_term: definitive surgical resection
term:
id: NCIT:C154430
label: Definitive Surgical Resection
evidence:
- reference: PMID:30666469
reference_title: Management of Residual Mass in Germ Cell Tumors After Chemotherapy.
supports: SUPPORT
evidence_source: OTHER
snippet: >-
All patients with primary mediastinal non-seminoma should undergo surgical
resection of the mediastinal mass post-chemotherapy. These are complex
surgeries and require expert surgeons in high-volume centers.
explanation: The review directly supports site-specific residual-mass surgery.
- name: Component-Directed Therapy for Somatically Derived Ovarian YST
description: >-
When a YST component arises with an ovarian epithelial malignancy, adjuvant
platinum-based therapy should be selected to address both the epithelial
carcinoma and germ-cell-like components. Evidence is sparse and no ideal
regimen is established, so this must not be managed as routine pure YST without review.
therapeutic_modality: SMALL_MOLECULE
treatment_term:
preferred_term: chemotherapy
term:
id: NCIT:C15632
label: Chemotherapy
evidence:
- reference: PMID:30113473
reference_title: "Ovarian yolk sac tumor in postmenopausal females: A case series and a literature review."
supports: SUPPORT
evidence_source: OTHER
snippet: >-
When YST mixed with epithelial cancer components, adjuvant chemotherapy
regimen should include platinum-based chemotherapy aiming at both
epithelial ovarian cancer and germ cell tumors.
explanation: >-
The review offers component-directed guidance, but its small case base
does not establish a single regimen.
- name: Surveillance After Complete Stage I Resection
description: >-
Selected children with completely resected stage I ovarian or testicular
malignant germ cell tumors can undergo intensive marker/imaging surveillance
with prompt salvage chemotherapy at recurrence. This is protocol-defined and
is not a blanket surgery-only recommendation for every stage I adult or site.
treatment_term:
preferred_term: active surveillance
evidence:
- reference: PMID:24395845
reference_title: >-
Surveillance after initial surgery for pediatric and adolescent girls
with stage I ovarian germ cell tumors: report from the Children's Oncology Group.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Fifty percent of patients with stage I pediatric MOGCT can be spared
chemotherapy; treatment for those who experience recurrence preserves OS.
explanation: The prospective pediatric ovarian study supports a selected surveillance strategy.
- name: Neoadjuvant Chemotherapy for Selected Advanced Ovarian YST
description: >-
For advanced ovarian YST with high tumor burden or poor operative tolerance,
neoadjuvant chemotherapy followed by interval surgery is an option. Evidence
is retrospective and includes mixed tumors containing YST elements.
therapeutic_modality: SMALL_MOLECULE
treatment_term:
preferred_term: neoadjuvant chemotherapy
term:
id: NCIT:C15632
label: Chemotherapy
evidence:
- reference: PMID:37696647
reference_title: Advanced ovarian yolk sac tumor. Upfront surgery or neoadjuvant chemotherapy followed by interval debulking?
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
For patients with advanced-stage ovarian yolk sac tumor, neoadjuvant
chemotherapy followed by interval surgery is an alternative option,
especially for those who cannot tolerate the primary debulking surgery
because of high tumor burden and vulnerable status.
explanation: The 40-patient retrospective comparison supports this selected alternative.
animal_models:
- name: Testicular YST patient-derived xenograft
species: Mus musculus
genotype: Patient-derived xenografts from a pediatric testicular yolk sac tumor
category: Patient-derived xenograft
description: >-
Testicular YST tissue was serially passaged in immunodeficient NPG and
BALB/c nude mice, retaining Schiller-Duval morphology and AFP/SALL4
expression. JEB sensitivity was tested in vivo and ex vivo. This single
patient-derived preclinical model does not establish clinical efficacy or
represent ovarian, mediastinal, CNS, mixed, or somatically derived YST.
modeled_mechanisms:
- target: Primitive Endodermal Differentiation Program
relationship: RECAPITULATES
fidelity: MODERATE
description: >-
The human testicular YST xenograft preserves characteristic yolk-sac
morphology together with the source tumor's AFP/SALL4 expression profile,
reproducing assayable features of primitive endodermal differentiation.
limitations: >-
This is a single pediatric testicular tumor propagated subcutaneously in
immunodeficient mice. Morphology and two diagnostic proteins support the
link, but do not establish fidelity across other YST sites, ages, mixed
tumors, immune contexts, or the full differentiation program.
evidence:
- reference: PMID:41525035
reference_title: Establishment and characterization of a testicular yolk sac tumor PDX model.
supports: SUPPORT
evidence_source: MODEL_ORGANISM
snippet: >-
H&E staining confirmed preservation of characteristic yolk sac morphology,
including Schiller-Duval bodies. Immunohistochemical analysis demonstrated
consistent expression of AFP and SALL4 in PDX tumors, mirroring the
diagnostic profile of the original specimen.
explanation: >-
Preserved morphology plus AFP/SALL4 expression directly grounds the
model-to-mechanism link; moderate fidelity reflects its single-patient,
immunodeficient xenograft context.
evidence:
- reference: PMID:41525035
reference_title: Establishment and characterization of a testicular yolk sac tumor PDX model.
supports: SUPPORT
evidence_source: MODEL_ORGANISM
snippet: >-
The patient-derived TYST tumor tissues exhibited higher tumorigenicity in
NPG and BALB/c nude mice, maintaining stability through serial passaging.
explanation: The study directly establishes and serially passages the mouse PDX.
- reference: PMID:41525035
reference_title: Establishment and characterization of a testicular yolk sac tumor PDX model.
supports: SUPPORT
evidence_source: MODEL_ORGANISM
snippet: >-
Immunohistochemical analysis demonstrated consistent expression of AFP
and SALL4 in PDX tumors, mirroring the diagnostic profile of the original specimen.
explanation: The PDX preserved the source tumor's key protein-expression profile.
clinical_trials:
- name: NCT03067181
phase: PHASE_III
description: >-
This phase III germ cell tumor trial studies active surveillance after
removal of low-risk tumors and compares carboplatin with cisplatin for
metastatic standard-risk disease. The generated cache does not expose
YST-specific stage, site, or mixed-tumor eligibility, so none is asserted
here and results must not be interpreted as YST-specific without
histology- and site-resolved reporting.
evidence:
- reference: clinicaltrials:NCT03067181
reference_title: >-
A Phase 3 Study of Active Surveillance for Low Risk and a Randomized Trial
of Carboplatin vs. Cisplatin for Standard Risk Pediatric and Adult Patients
With Germ Cell Tumors
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
The trial studies whether carboplatin or cisplatin is the preferred
chemotherapy to use in treating metastatic standard risk germ cell tumors.
explanation: The current registry summary defines the randomized platinum question.
datasets:
- accession: geo:GSE281147
title: MicroRNA-371-373 cluster and methylome analysis suggests that a subset of “somatic-type” malignancies arising in germ cell tumors may originate in yolk sac tumor components
description: 'Background: Somatic-type malignancies (SM) arising in germ cell tumors (GCTs) represent aggressive and chemoresistant neoplasms frequently occurring as metastases after chemotherapy. Historically, SM have been interpreted as originating in teratoma; however, recent observations suggest that a subset may derive from yolk sac tumor. In this study, we evaluate the relationship between conventional histologic types of GCT and SM of germ cell origin by assessing expression of miR-371~373 and genomic methylation.'
organism:
preferred_term: human
term:
id: NCBITaxon:9606
label: Homo sapiens
data_type: METHYLATION
sample_count: 51
publication: PMID:40152072
notes: Identified by GEO DataSets index search for Yolk Sac Tumor (scripts/discover_datasets.py); accession and metadata verified against NCBI E-utilities on 2026-08-01. Title, sample count, and organism are GEO's own values.
- accession: geo:GSE169733
title: Genomic Landscape, Evolution and Chemoresistance of Yolk Sac Tumors
data_type: BULK_RNA_SEQ
organism:
preferred_term: human
term:
id: NCBITaxon:9606
label: Homo sapiens
publication: PMID:34117242
notes: >-
This GEO series is linked to the ovarian YST sequencing study. The cached
summary does not establish a sample count for a processed-expression subset
or raw-data availability, so neither is asserted here. It should not be treated as representative
of every pediatric, testicular, mediastinal, CNS, or somatically derived YST.
evidence:
- reference: GEO:GSE169733
reference_title: Genomic Landscape, Evolution and Chemoresistance of Yolk Sac Tumors
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Here we characterized 41 clinical tumor samples (and related normal
samples) from 30 YST patients, with distinct responses to
cisplatin_x001f__x001F_-based chemotherapy, through a combination of
whole-exome and RNA sequencing.
explanation: The GEO summary establishes the linked human ovarian YST sequencing cohort.
- accession: geo:GSE276475
title: Chromatin-immunoprecipitation followed by sequencing (ChIPseq) of SOX17 and FOXA2 in yolk-sac tumor cell lines
description: ChIPseq of SOX17 and FOXA2 in yolk-sac tumor cell lines GCT72 and 1411H
organism:
preferred_term: human
term:
id: NCBITaxon:9606
label: Homo sapiens
data_type: CHIP_SEQ
sample_count: 16
publication: PMID:40025812
notes: Identified by GEO DataSets index search for Yolk Sac Tumor (scripts/discover_datasets.py); accession and metadata verified against NCBI E-utilities on 2026-08-01. Title, sample count, and organism are GEO's own values.
classifications:
icdo_morphology:
classification_value: Germ Cell Tumor
notes: >-
Yolk sac tumour is a non-germinomatous germ cell neoplasm; NCIT:C3011
(Yolk Sac Tumor) descends from NCIT:C3708 (Germ Cell Tumor), the term
this enum value is bound to.
discussions:
- discussion_id: gap_yst_histogenesis_across_contexts
prompt: >-
Which precursor cells and developmental trajectories generate
prepubertal-type, postpubertal GCNIS-related, ovarian, extragonadal, CNS, and somatically
derived YST, and which molecular events are shared versus context-specific?
kind: KNOWLEDGE_GAP
status: OPEN
attaches_to:
- pathophysiology#Primitive Endodermal Differentiation Program
- pathophysiology#Childhood Malignant-GCT Chromosomal-Imbalance Pattern
- pathophysiology#Postpubertal GCNIS-Related 12p-Gain Pathway
- pathophysiology#Somatic-Lineage Plasticity to YST Differentiation
rationale: >-
Morphologic convergence on primitive endoderm does not prove common origin.
Pediatric and postpubertal testicular tumors differ in GCNIS and 12p biology;
SNP-array analysis also found several histogenetic routes and intratumoral
genomic differences. Cross-sectional tumors cannot directly reconstruct the lineage.
evidence:
- reference: PMID:34561860
reference_title: Molecular genetic evidence supporting diverse histogenic origins of germ cell tumors.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Our data indicate that GCTs may have various histogenesis and intratumoral
genomic differences, which might provide important information for the
identification of GCTs, especially for those with different histologic areas.
explanation: The SNP-array study directly supports diverse origins and within-tumor genomic differences.
- discussion_id: gap_yst_chemoresistance_validation
prompt: >-
Which genomic, epigenomic, transcriptional, and microenvironmental features
reproducibly predict primary or acquired platinum resistance in YST, and do
they generalize beyond ovarian cohorts?
kind: KNOWLEDGE_GAP
status: OPEN
attaches_to:
- pathophysiology#Ovarian YST Somatic-Driver Landscape
rationale: >-
The principal ovarian sequencing cohort associated MSI-related signatures
and OVOL2 overexpression with resistance, but sample numbers were small and
the authors called for independent validation. Relapsed tumors may reflect
therapy selection, and findings cannot yet be generalized to pediatric,
testicular, mediastinal, or CNS YST.
evidence:
- reference: PMID:34117242
reference_title: Analysis of the genomic landscape of yolk sac tumors reveals mechanisms of evolution and chemoresistance.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
This study lays a critical foundation for understanding key molecular
aberrations in YSTs and developing related therapeutic strategies.
explanation: The authors characterize the work as a foundation rather than a validated clinical biomarker set.
- discussion_id: gap_yst_component_specific_outcomes
prompt: >-
What treatment effects and outcomes are attributable to a YST component
itself after stratifying pure YST from mixed germ cell tumors by site, age,
stage, component proportion, treatment, and somatically derived status?
kind: KNOWLEDGE_GAP
status: OPEN
rationale: >-
Many clinical series combine pure YST, mixed tumors containing YST, and
marker-defined putative YST. Overall-tumor behavior cannot be assigned to a
microscopic component without component-resolved pathology and molecular
analysis. Rare extragonadal sites and somatically derived YST are especially underpowered.
evidence:
- reference: PMID:29194189
reference_title: Ovarian Yolk Sac Tumors; Does Age Matter?
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Histology was pure, mixed, and putative in 129, 56, and 66 cases, respectively.
explanation: The largest pooled ovarian analysis illustrates the mixed evidentiary strata.
- discussion_id: gap_yst_site_specific_staging_harmonization
prompt: >-
How can pediatric and adult, ovarian and testicular, extracranial and CNS
staging/risk systems be harmonized for comparative YST research without
erasing clinically meaningful site-specific distinctions?
kind: KNOWLEDGE_GAP
status: OPEN
rationale: >-
Current care correctly stages the whole tumor using site-specific systems,
but that complicates cross-study comparison. A harmonized research mapping
needs central pathology, explicit pure-versus-mixed component annotation,
and parallel retention of the native clinical stage.
references:
- reference: PMID:22008025
title: Yolk sac tumours revisited. A review of their many faces and names.
- reference: PMID:19574883
title: "Diagnostic utility of SALL4 in extragonadal yolk sac tumors: an immunohistochemical study of 59 cases with comparison to placental-like alkaline phosphatase, alpha-fetoprotein, and glypican-3."
- reference: PMID:32222813
title: SALL4 is a useful marker for pediatric yolk sac tumors.
- reference: PMID:34117242
title: Analysis of the genomic landscape of yolk sac tumors reveals mechanisms of evolution and chemoresistance.
- reference: GEO:GSE169733
title: Genomic Landscape, Evolution and Chemoresistance of Yolk Sac Tumors
- reference: PMID:34561860
title: Molecular genetic evidence supporting diverse histogenic origins of germ cell tumors.
- reference: PMID:11528555
title: Genetic analysis of childhood germ cell tumors with comparative genomic hybridization.
- reference: PMID:18302061
title: Influence of tumor site and histology on long-term survival in 193 children with extracranial germ cell tumors.
- reference: PMID:25828390
title: Yolk Sac Tumor of the Testis in Infants and Children. A Clinicopathologic Analysis of 33 Cases.
- reference: PMID:35606324
title: "Clinicopathologic predictors of outcomes in children with stage I testicular germ cell tumors: A pooled post hoc analysis of trials from the Children's Oncology Group."
- reference: PMID:37696647
title: Advanced ovarian yolk sac tumor. Upfront surgery or neoadjuvant chemotherapy followed by interval debulking?
- reference: PMID:37747514
title: "Clinical characteristics and prognostic models of gonadal and extra-gonadal yolk sac tumors: a population-based analysis in children and adolescents."
- reference: PMID:9354734
title: Actual half-life of alpha-fetoprotein as a prognostic tool in pediatric malignant tumors.
- reference: PMID:19245437
title: Yolk sac tumor but not seminoma or teratoma is associated with abnormal epigenetic reprogramming pathway and shows frequent hypermethylation of various tumor suppressor genes.
- reference: PMID:29194189
title: Ovarian Yolk Sac Tumors. Does Age Matter?
- reference: PMID:24395845
title: "Surveillance after initial surgery for pediatric and adolescent girls with stage I ovarian germ cell tumors: report from the Children's Oncology Group."
- reference: PMID:41384700
title: Molecular pathology of testicular germ cell tumours. An update for practicing pathologists.
- reference: clinicaltrials:NCT03067181
title: >-
A Phase 3 Study of Active Surveillance for Low Risk and a Randomized Trial
of Carboplatin vs. Cisplatin for Standard Risk Pediatric and Adult Patients With Germ Cell Tumors
- reference: PMID:6163129
title: Serum alpha fetoprotein (AFP) levels in normal infants.
- reference: PMID:11078494
title: "The United Kingdom Children's Cancer Study Group's second germ cell tumor study: carboplatin, etoposide, and bleomycin are effective treatment for children with malignant extracranial germ cell tumors, with acceptable toxicity."
- reference: PMID:38958901
title: SEOM-GG clinical guidelines for the management of germ-cell testicular cancer (2023).
- reference: PMID:35554637
title: How to classify, diagnose, treat and follow-up extragonadal germ cell tumors? A systematic review of available evidence.
- reference: PMID:30666469
title: Management of Residual Mass in Germ Cell Tumors After Chemotherapy.
- reference: PMID:41789737
title: Incidence of Gonadal and Extragonadal Germ Cell Tumours in Patients With Klinefelter Syndrome.
- reference: PMID:10620634
title: Hematologic disorders associated with primary mediastinal nonseminomatous germ cell tumors.
- reference: PMID:32897884
title: Germ cell tumors and associated hematologic malignancies evolve from a common shared precursor.
- reference: PMID:30113473
title: "Ovarian yolk sac tumor in postmenopausal females: A case series and a literature review."
- reference: PMID:19295406
title: SALL4 is a novel sensitive and specific marker of ovarian primitive germ cell tumors and is particularly useful in distinguishing yolk sac tumor from clear cell carcinoma.
- reference: PMID:19820689
title: "Diagnostic utility of SALL4 in primary germ cell tumors of the central nervous system: a study of 77 cases."
- reference: PMID:41001186
title: Updates in the Management of Malignant Ovarian Germ Cell Tumors.
- reference: PMID:40037273
title: "Acute abdominopelvic pain and distension in a 21-year-old woman revealing a mixed germ cell tumor: A case report."
- reference: PMID:40818404
title: "Pediatric vaginal yolk sac tumor: A rare case report and diagnostic challenges."
- reference: PMID:25395492
title: "The yolk sac tumor: reflections on a remarkable neoplasm and two of the many intrigued by it-Gunnar Teilum and Aleksander Talerman-and the bond it formed between them."
- reference: PMID:41525035
title: Establishment and characterization of a testicular yolk sac tumor PDX model.
- reference: PMID:37317674
title: FoxA2 is a reliable marker for the diagnosis of yolk sac tumour postpubertal-type.
References & Deep Research
References
35Yolk sac tumours revisited. A review of their many faces and names.
No top-level findings curated for this source.
Diagnostic utility of SALL4 in extragonadal yolk sac tumors: an immunohistochemical study of 59 cases with comparison to placental-like alkaline phosphatase, alpha-fetoprotein, and glypican-3.
No top-level findings curated for this source.
SALL4 is a useful marker for pediatric yolk sac tumors.
No top-level findings curated for this source.
Analysis of the genomic landscape of yolk sac tumors reveals mechanisms of evolution and chemoresistance.
No top-level findings curated for this source.
Genomic Landscape, Evolution and Chemoresistance of Yolk Sac Tumors
No top-level findings curated for this source.
Molecular genetic evidence supporting diverse histogenic origins of germ cell tumors.
No top-level findings curated for this source.
Genetic analysis of childhood germ cell tumors with comparative genomic hybridization.
No top-level findings curated for this source.
Influence of tumor site and histology on long-term survival in 193 children with extracranial germ cell tumors.
No top-level findings curated for this source.
Yolk Sac Tumor of the Testis in Infants and Children. A Clinicopathologic Analysis of 33 Cases.
No top-level findings curated for this source.
Clinicopathologic predictors of outcomes in children with stage I testicular germ cell tumors: A pooled post hoc analysis of trials from the Children's Oncology Group.
No top-level findings curated for this source.
Advanced ovarian yolk sac tumor. Upfront surgery or neoadjuvant chemotherapy followed by interval debulking?
No top-level findings curated for this source.
Clinical characteristics and prognostic models of gonadal and extra-gonadal yolk sac tumors: a population-based analysis in children and adolescents.
No top-level findings curated for this source.
Actual half-life of alpha-fetoprotein as a prognostic tool in pediatric malignant tumors.
No top-level findings curated for this source.
Yolk sac tumor but not seminoma or teratoma is associated with abnormal epigenetic reprogramming pathway and shows frequent hypermethylation of various tumor suppressor genes.
No top-level findings curated for this source.
Ovarian Yolk Sac Tumors. Does Age Matter?
No top-level findings curated for this source.
Surveillance after initial surgery for pediatric and adolescent girls with stage I ovarian germ cell tumors: report from the Children's Oncology Group.
No top-level findings curated for this source.
Molecular pathology of testicular germ cell tumours. An update for practicing pathologists.
No top-level findings curated for this source.
A Phase 3 Study of Active Surveillance for Low Risk and a Randomized Trial of Carboplatin vs. Cisplatin for Standard Risk Pediatric and Adult Patients With Germ Cell Tumors
No top-level findings curated for this source.
Serum alpha fetoprotein (AFP) levels in normal infants.
No top-level findings curated for this source.
The United Kingdom Children's Cancer Study Group's second germ cell tumor study: carboplatin, etoposide, and bleomycin are effective treatment for children with malignant extracranial germ cell tumors, with acceptable toxicity.
No top-level findings curated for this source.
SEOM-GG clinical guidelines for the management of germ-cell testicular cancer (2023).
No top-level findings curated for this source.
How to classify, diagnose, treat and follow-up extragonadal germ cell tumors? A systematic review of available evidence.
No top-level findings curated for this source.
Management of Residual Mass in Germ Cell Tumors After Chemotherapy.
No top-level findings curated for this source.
Incidence of Gonadal and Extragonadal Germ Cell Tumours in Patients With Klinefelter Syndrome.
No top-level findings curated for this source.
Hematologic disorders associated with primary mediastinal nonseminomatous germ cell tumors.
No top-level findings curated for this source.
Germ cell tumors and associated hematologic malignancies evolve from a common shared precursor.
No top-level findings curated for this source.
Ovarian yolk sac tumor in postmenopausal females: A case series and a literature review.
No top-level findings curated for this source.
SALL4 is a novel sensitive and specific marker of ovarian primitive germ cell tumors and is particularly useful in distinguishing yolk sac tumor from clear cell carcinoma.
No top-level findings curated for this source.
Diagnostic utility of SALL4 in primary germ cell tumors of the central nervous system: a study of 77 cases.
No top-level findings curated for this source.
Updates in the Management of Malignant Ovarian Germ Cell Tumors.
No top-level findings curated for this source.
Acute abdominopelvic pain and distension in a 21-year-old woman revealing a mixed germ cell tumor: A case report.
No top-level findings curated for this source.
Pediatric vaginal yolk sac tumor: A rare case report and diagnostic challenges.
No top-level findings curated for this source.
The yolk sac tumor: reflections on a remarkable neoplasm and two of the many intrigued by it-Gunnar Teilum and Aleksander Talerman-and the bond it formed between them.
No top-level findings curated for this source.
Establishment and characterization of a testicular yolk sac tumor PDX model.
No top-level findings curated for this source.
FoxA2 is a reliable marker for the diagnosis of yolk sac tumour postpubertal-type.
No top-level findings curated for this source.
Deep Research
1
Falcon
▸
Question: You are an expert researcher providing comprehensive, well-cited information.
Provide detailed information focusing on: 1. Key concepts and definitions with current understanding 2. Recent developments and latest research (prioritize 2023-2024 sources) 3. Current applications and real-world implementations 4. Expert opinions and analysis from authoritative sources 5. Relevant statistics and data from recent studies
Format as a comprehensive research report with proper citations. Include URLs and publication dates where available. Always prioritize recent, authoritative sources and provide specific citations for all major claims.
Disease Characteristics Research Template
Target Disease
- Disease Name: Yolk Sac Tumor
- MONDO ID: (if available)
- Category: Complex
Research Objectives
Please provide a comprehensive research report on Yolk Sac Tumor covering all of the disease characteristics listed below. This report will be used to populate a disease knowledge base entry. Be thorough and cite primary literature (PMID preferred) for all claims.
For each section, suggested databases/resources are listed. These are the first places you should search for information on each topic.
1. Disease Information
Search first: OMIM, Orphanet, ICD-10/ICD-11, MeSH, PubMed
- What is the disease? Provide a concise overview.
- What are the key identifiers? (OMIM, Orphanet, ICD-10/ICD-11, MeSH, Mondo)
- What are the common synonyms and alternative names?
- Is the information derived from individual patients (e.g., EHR) or aggregated disease-level resources?
2. Etiology
- Disease Causal Factors: What are the primary causes? (genetic, environmental, infectious, mechanistic)
- Risk Factors:
Search first: PubMed, Cochrane Library, UpToDate, clinical guidelines, ClinVar, ClinGen, GWAS Catalog, PheGenI, CTD, CDC, WHO, epidemiological databases
- Genetic risk factors (causal variants, susceptibility loci, modifier genes)
- Environmental risk factors (toxins, lifestyle, occupational exposures, age, sex, family history)
- Protective Factors:
Search first: PubMed, Cochrane Library, clinical trial databases, GWAS Catalog, gnomAD, WHO, CDC, nutrition databases
- Genetic protective factors (protective variants, modifier alleles)
- Environmental protective factors (diet, lifestyle, exposures that reduce risk)
- Gene-Environment Interactions: How do genetic and environmental factors interact to influence disease?
Search first: CTD, PubMed, PheGenI, GxE databases
3. Phenotypes
Search first: HPO (Human Phenotype Ontology), OMIM, Orphanet, PubMed, clinicaltrials.gov, MedDRA, SNOMED CT, DECIPHER, LOINC
For each phenotype, provide: - Phenotype type: symptoms, clinical signs, physical manifestations, behavioral changes, or laboratory abnormalities
For symptoms/signs: HPO, OMIM, Orphanet, PubMed For behavioral changes: HPO, DSM, RDoC (Research Domain Criteria), PubMed For laboratory abnormalities: LOINC, SNOMED CT, LabTests Online, PubMed - Phenotype characteristics: Search first: OMIM, Orphanet, HPO, PubMed - Age of symptom onset (neonatal, childhood, adult-onset, late-onset) - Symptom severity (mild, moderate, severe, variable) - Symptom progression (stable, progressive, episodic, fluctuating) - Frequency among affected individuals (percentage or qualitative) - Quality of life impact: Effects on daily functioning and well-being (per-phenotype when possible) Search first: EQ-5D database, SF-36, WHO QOL databases, PubMed - Suggest HPO (Human Phenotype Ontology) terms for each phenotype
4. Genetic/Molecular Information
- Causal Genes: Gene mutations or chromosomal abnormalities responsible for disease (gene symbols, OMIM IDs)
Search first: OMIM, ClinVar, HGMD, Ensembl, NCBI Gene
- Pathogenic Variants:
- Affected genes (gene symbols, HGNC IDs) > Search first: OMIM, NCBI Gene, Ensembl, HGNC, UniProt, GeneCards
- Variant classification (pathogenic, likely pathogenic, VUS per ACMG/AMP guidelines) > Search first: ClinVar, ClinGen, ACMG/AMP guidelines, VarSome
- Variant type/class (missense, frameshift, nonsense, splice-site, structural)
- Allele frequency in population databases > Search first: gnomAD, 1000 Genomes, ExAC, TOPMed, dbSNP
- Somatic vs germline origin > Search first: COSMIC (somatic), ClinVar, ICGC, TCGA
- Functional consequences (loss of function, gain of function, dominant negative)
- Modifier Genes: Genes that modify disease severity or expression
- Epigenetic Information: DNA methylation, histone modifications, chromatin changes affecting disease
Search first: ENCODE, Roadmap Epigenomics, MethBase, DiseaseMeth
- Chromosomal Abnormalities: Large-scale genetic changes (aneuploidy, translocations, inversions)
Search first: DECIPHER, ClinVar, ECARUCA, UCSC Genome Browser
5. Environmental Information
- Environmental Factors: Non-genetic contributing factors (toxins, radiation, pollution, occupational exposure)
Search first: CTD (Comparative Toxicogenomics Database), TOXNET, PubMed, EPA databases
- Lifestyle Factors: Behavioral factors (smoking, diet, exercise, alcohol consumption)
Search first: CDC databases, WHO, PubMed, NHANES
- Infectious Agents: If applicable, pathogens causing or triggering disease (bacteria, viruses, fungi, parasites)
Search first: NCBI Taxonomy, ViPR, BV-BRC, MicrobeDB, GIDEON
6. Mechanism / Pathophysiology
- Molecular Pathways: Specific signaling cascades or biochemical pathways involved (Wnt, MAPK, mTOR, PI3K-AKT, etc.)
Search first: KEGG, Reactome, WikiPathways, PathBank, BioCyc
- Cellular Processes: Cell-level mechanisms (apoptosis, autophagy, cell cycle dysregulation, inflammation, etc.)
Search first: Gene Ontology (GO), Reactome, KEGG, PubMed
- Protein Dysfunction: How protein structure or function is altered (misfolding, aggregation, loss of function, gain of function)
Search first: UniProt, PDB (Protein Data Bank), InterPro, Pfam, AlphaFold
- Metabolic Changes: Alterations in metabolic processes (energy metabolism, lipid metabolism, amino acid metabolism)
Search first: KEGG, BioCyc, HMDB (Human Metabolome Database), BRENDA
- Immune System Involvement: Role of immune response (autoimmunity, immunodeficiency, chronic inflammation)
Search first: ImmPort, Immunome Database, IEDB, Gene Ontology
- Tissue Damage Mechanisms: How tissues/ are injured (oxidative stress, ischemia, fibrosis, necrosis)
Search first: PubMed, Gene Ontology, Reactome
- Biochemical Abnormalities: Specific molecular defects (enzyme deficiencies, receptor dysfunction, ion channel defects)
Search first: BRENDA, UniProt, KEGG, OMIM, PubMed
- Epigenetic Changes: DNA methylation, histone modifications affecting gene expression in disease
Search first: ENCODE, Roadmap Epigenomics, MethBase, DiseaseMeth
- Molecular Profiling (if available):
- Transcriptomics/gene expression changes > Search first: GEO (Gene Expression Omnibus), ArrayExpress, GTEx, Human Cell Atlas, SRA
- Proteomics findings > Search first: PRIDE, ProteomeXchange, Human Protein Atlas, STRING, BioGRID
- Metabolomics signatures > Search first: MetaboLights, Metabolomics Workbench, HMDB, METLIN
- Lipidomics alterations > Search first: LIPID MAPS, SwissLipids, LipidHome, Metabolomics Workbench
- Genomic structural features > Search first: UCSC Genome Browser, Ensembl, NCBI, dbVar, DGV
- Advanced Technologies (if applicable):
- Single-cell analysis findings (cell-type specific mechanisms, cellular heterogeneity) > Search first: Human Cell Atlas, Single Cell Portal, GEO, CELLxGENE
- Spatial transcriptomics findings > Search first: GEO, Spatial Research, Vizgen, 10x Genomics data
- Multi-omics integration results > Search first: TCGA, ICGC, cBioPortal, LinkedOmics, PubMed
- Functional genomics screens (CRISPR, RNAi) > Search first: DepMap, GenomeRNAi, PubMed, BioGRID ORCS
For each mechanism, describe: - The causal chain from initial trigger to clinical manifestation - Which mechanisms are upstream vs downstream - What cell types and biological processes are involved - Suggest GO terms for biological processes and CL terms for cell types
7. Anatomical Structures Affected
- Organ Level:
- Primary organs directly affected
- Secondary organ involvement (complications, secondary effects)
- Body systems involved (cardiovascular, nervous, digestive, respiratory, endocrine, etc.)
Search first: Uberon, FMA (Foundational Model of Anatomy), OMIM, HPO, ICD-11, MeSH, SNOMED CT
- Tissue and Cell Level:
- Specific tissue types affected (epithelial, connective, muscle, nervous)
- Specific cell populations targeted (with Cell Ontology terms)
Search first: Uberon, Human Protein Atlas, Cell Ontology, Human Cell Atlas, CellMarker, PanglaoDB
- Subcellular Level:
- Cellular compartments involved (mitochondria, nucleus, ER, lysosomes) (with GO Cellular Component terms)
Search first: Gene Ontology (Cellular Component), UniProt, Human Protein Atlas
- Localization:
- Specific anatomical sites (with UBERON terms) > Search first: FMA, Uberon, NeuroNames (for brain), SNOMED CT
- Lateralization (unilateral, bilateral, asymmetric) > Search first: HPO, clinical literature, imaging databases
8. Temporal Development
- Onset:
- Typical age of onset (congenital, pediatric, adult, geriatric)
- Onset pattern (acute, subacute, chronic, insidious)
Search first: OMIM, Orphanet, HPO, PubMed
- Progression:
- Disease stages (early, intermediate, advanced, end-stage) > Search first: Cancer Staging Manual (AJCC), WHO classifications, PubMed
- Progression rate (rapid, slow, variable)
- Disease course pattern (episodic, relapsing-remitting, progressive, stable)
- Disease duration (self-limited, chronic lifelong)
Search first: Disease registries, longitudinal cohort databases, natural history studies, PubMed, Orphanet, OMIM
- Patterns:
- Remission patterns (spontaneous, treatment-induced) > Search first: Clinical trial databases, disease registries, PubMed
- Critical periods (time windows of vulnerability or opportunity for intervention) > Search first: PubMed, developmental biology databases, clinical guidelines
9. Inheritance and Population
- Epidemiology:
- Prevalence (cases per 100,000 at given time)
- Incidence (new cases per 100,000 per year)
Search first: Orphanet, CDC, WHO, GBD (Global Burden of Disease), national registries, SEER, disease registries
- For Genetic Etiology:
- Inheritance pattern (AD, AR, X-linked, mitochondrial, multifactorial, polygenic) > Search first: OMIM, Orphanet, ClinVar, GTR (Genetic Testing Registry)
- Penetrance (complete, incomplete, age-dependent) > Search first: ClinVar, OMIM, PubMed, ClinGen
- Expressivity (variable, consistent) > Search first: OMIM, ClinVar, PubMed
- Genetic anticipation (increasing severity in successive generations) > Search first: OMIM, PubMed (especially for repeat expansion disorders)
- Germline mosaicism > Search first: ClinVar, OMIM, genetic counseling literature, PubMed
- Founder effects (population-specific mutations) > Search first: gnomAD, population genetics databases, PubMed
- Consanguinity role > Search first: OMIM, population studies, genetic counseling resources
- Carrier frequency > Search first: gnomAD, carrier screening databases, GeneReviews, GTR
- Population Demographics:
- Affected populations (ethnic or demographic groups with higher prevalence) > Search first: gnomAD, 1000 Genomes, PAGE Study, PubMed, population registries
- Geographic distribution (endemic areas, regional variation) > Search first: WHO, CDC, GBD, Orphanet, geographic epidemiology databases
- Geographic distribution of specific variants
- Sex ratio (male:female) > Search first: Disease registries, OMIM, PubMed, epidemiological databases
- Age distribution of affected individuals > Search first: CDC, disease registries, SEER, Orphanet
10. Diagnostics
- Clinical Tests:
- Laboratory tests (blood, urine, tissue chemistry, specific enzyme assays) > Search first: LOINC, LabTests Online, PubMed
- Biomarkers (proteins, metabolites, genetic markers, circulating biomarkers) > Search first: FDA Biomarker List, BEST (Biomarkers, EndpointS, and other Tools), PubMed
- Imaging studies (X-ray, CT, MRI, PET, ultrasound) > Search first: RadLex, DICOM, Radiopaedia, imaging databases
- Functional tests (pulmonary function, cardiac stress tests) > Search first: LOINC, clinical guidelines, PubMed
- Electrophysiology (EEG, EMG, ECG, nerve conduction studies) > Search first: LOINC, clinical neurophysiology databases, PubMed
- Biopsy findings (histopathology, immunohistochemistry) > Search first: SNOMED CT, College of American Pathologists resources, PubMed
- Pathology findings (microscopic examination) > Search first: SNOMED CT, Digital Pathology databases, PubMed
- Genetic Testing:
Search first: GTR (Genetic Testing Registry), GeneReviews, ClinGen
- Overview of recommended genetic testing approach
- Whole genome sequencing (WGS) utility > Search first: GTR, ClinVar, GEL (Genomics England), gnomAD
- Whole exome sequencing (WES) utility > Search first: GTR, ClinVar, OMIM, GeneMatcher
- Gene panels (which panels, which genes) > Search first: GTR, ClinVar, laboratory-specific databases
- Single gene testing > Search first: GTR, ClinVar, OMIM, GeneReviews
- Chromosomal microarray (CMA) > Search first: DECIPHER, ClinVar, dbVar, ECARUCA
- Karyotyping > Search first: Chromosome Abnormality Database, ClinVar, cytogenetics resources
- FISH > Search first: ClinVar, cytogenetics databases, PubMed
- Mitochondrial DNA testing > Search first: MITOMAP, MSeqDR, ClinVar, GTR
- Repeat expansion testing > Search first: GTR, ClinVar, repeat expansion databases, PubMed
- Omics-Based Diagnostics (if applicable):
- RNA sequencing / transcriptomics > Search first: GEO, ArrayExpress, GTEx, RNA-seq databases
- Proteomics > Search first: PRIDE, ProteomeXchange, FDA Biomarker database
- Metabolomics > Search first: MetaboLights, Metabolomics Workbench, HMDB
- Epigenomics > Search first: GEO, ENCODE, Roadmap Epigenomics, MethBase
- Liquid biopsy > Search first: COSMIC, ClinVar, liquid biopsy databases, PubMed
- Clinical Criteria:
- Standardized diagnostic criteria (DSM, ICD, society guidelines) > Search first: DSM-5, ICD-11, clinical society guidelines, UpToDate
- Differential diagnosis (other conditions to rule out, with distinguishing features) > Search first: DynaMed, UpToDate, clinical decision support systems
- Screening:
- Screening methods for asymptomatic individuals (newborn screening, carrier screening, cascade screening) > Search first: ACMG recommendations, CDC newborn screening, GTR
11. Outcome/Prognosis
- Survival and Mortality:
- Survival rate (5-year, 10-year, overall) > Search first: SEER, cancer registries, disease-specific registries, PubMed
- Life expectancy (with and without treatment if applicable) > Search first: Orphanet, disease registries, actuarial databases, PubMed
- Mortality rate > Search first: CDC, WHO, GBD, national mortality databases
- Disease-specific mortality (deaths directly attributable to disease) > Search first: Disease registries, CDC Wonder, GBD, PubMed
- Morbidity and Function:
- Morbidity (disease-related disability and health impacts) > Search first: GBD, WHO, disability databases, PubMed
- Disability outcomes (long-term functional impairments) > Search first: ICF (International Classification of Functioning), disability registries
- Quality of life measures (EQ-5D, SF-36, PROMIS, disease-specific tools) > Search first: EQ-5D database, SF-36, PROMIS, PubMed
- Disease Course:
- Complications (secondary problems: infections, organ failure, etc.) > Search first: ICD codes, disease registries, clinical databases, PubMed
- Recovery potential (likelihood and extent of recovery, with vs without treatment) > Search first: Natural history studies, rehabilitation databases, PubMed
- Prediction:
- Prognostic factors (age, disease severity, biomarkers, treatment response) > Search first: Prognostic models databases, clinical calculators, PubMed
- Prognostic biomarkers (molecular markers predicting disease course) > Search first: FDA Biomarker database, PubMed, cancer prognostic databases
12. Treatment
- Pharmacotherapy:
- Pharmacological treatments (drug names, drug classes, mechanisms of action) > Search first: DrugBank, RxNorm, ATC classification, DailyMed, FDA databases
- Pharmacogenomics (how genetic variants affect drug metabolism, efficacy, toxicity) > Search first: PharmGKB, CPIC (Clinical Pharmacogenetics), FDA Table of PGx Biomarkers
- Advanced Therapeutics:
- Gene therapy (viral vectors, CRISPR, gene replacement, gene editing) > Search first: ClinicalTrials.gov, FDA gene therapy database, ASGCT resources
- Cell therapy (stem cell transplant, CAR-T, cellular therapeutics) > Search first: ClinicalTrials.gov, FDA cell therapy database, FACT standards
- RNA-based therapies (ASOs, siRNA, mRNA therapies) > Search first: ClinicalTrials.gov, FDA approvals, PubMed
- Targeted therapies (treatments directed at specific molecular targets) > Search first: My Cancer Genome, OncoKB, ClinicalTrials.gov, FDA approvals
- Immunotherapies (checkpoint inhibitors, monoclonal antibodies) > Search first: Cancer Immunotherapy Database, FDA approvals, ClinicalTrials.gov
- Surgical and Interventional:
- Surgical interventions (types of surgery, timing, outcomes) > Search first: CPT codes, surgical registries, clinical guidelines, PubMed
- Supportive and Rehabilitative:
- Supportive care (symptom management, pain control, nutrition) > Search first: Clinical guidelines, Cochrane Library, PubMed
- Rehabilitation (physical therapy, occupational therapy, speech therapy) > Search first: Rehabilitation medicine databases, clinical guidelines, PubMed
- Experimental:
- Experimental treatments in clinical trials (with NCT identifiers if available) > Search first: ClinicalTrials.gov, EU Clinical Trials Register, WHO ICTRP
- Treatment Outcomes:
- Treatment response rates > Search first: Clinical trial databases, FDA reviews, systematic reviews, PubMed
- Side effects and adverse events > Search first: FDA Adverse Event Reporting System (FAERS), MedWatch, PubMed
- Treatment Strategy:
- Treatment algorithms (clinical pathways, decision trees) > Search first: Clinical practice guidelines, NCCN Guidelines, UpToDate
- Combination therapies > Search first: ClinicalTrials.gov, treatment guidelines, PubMed
- Personalized medicine approaches (genotype-guided treatment) > Search first: My Cancer Genome, CIViC, PharmGKB, precision medicine databases
For each treatment, suggest MAXO (Medical Action Ontology) terms where applicable.
13. Prevention
- Prevention Levels:
- Primary prevention (preventing disease occurrence: vaccination, risk factor modification) > Search first: CDC, WHO, USPSTF recommendations, Cochrane Library
- Secondary prevention (early detection and treatment: screening programs, early intervention) > Search first: USPSTF, CDC screening guidelines, WHO
- Tertiary prevention (preventing complications in those with disease) > Search first: Clinical guidelines, disease management protocols, PubMed
- Immunization: Vaccine strategies (if applicable)
Search first: CDC vaccine schedules, WHO immunization, FDA vaccine database
- Screening and Early Detection:
- Screening programs (population-based: newborn screening, cancer screening) > Search first: CDC screening programs, USPSTF, cancer screening databases
- Genetic screening (carrier screening, preimplantation genetic diagnosis, prenatal testing) > Search first: ACMG recommendations, ACOG guidelines, GTR
- Risk stratification (identifying high-risk individuals for targeted prevention) > Search first: Risk prediction models, clinical calculators, PubMed
- Behavioral Interventions: Lifestyle modifications to reduce risk
Search first: CDC, WHO, behavioral intervention databases, Cochrane Library
- Counseling: Genetic counseling (risk assessment, family planning guidance)
Search first: NSGC resources, ACMG guidelines, GeneReviews
- Public Health:
- Public health interventions (sanitation, vector control, health education) > Search first: CDC, WHO, public health databases, PubMed
- Environmental interventions (reducing environmental risk factors) > Search first: EPA databases, WHO environmental health, PubMed
- Prophylaxis: Preventive medications or procedures
Search first: Clinical guidelines, FDA approvals, PubMed
14. Other Species / Natural Disease
- Taxonomy: Species affected (with NCBI Taxon identifiers)
Search first: NCBI Taxonomy
- Breed: Specific breeds affected (with VBO identifiers if applicable)
Search first: VBO (Vertebrate Breed Ontology)
- Gene: Orthologous genes in other species (with NCBI Gene IDs)
Search first: NCBI Gene
- Natural Disease:
- Naturally occurring disease in other species (companion animals, wildlife) > Search first: OMIA (Online Mendelian Inheritance in Animals), VetCompass, PubMed
- Veterinary relevance and importance in animal health > Search first: OMIA, veterinary databases, PubMed
- Comparative Biology:
- Comparative pathology (similarities and differences across species) > Search first: OMIA, comparative pathology databases, PubMed
- Evolutionary conservation of disease mechanisms > Search first: HomoloGene, OrthoMCL, Alliance of Genome Resources
- Transmission (if applicable):
- Zoonotic potential > Search first: CDC zoonotic diseases, WHO zoonoses, GIDEON
- Cross-species susceptibility > Search first: NCBI Taxonomy, veterinary databases, PubMed
15. Model Organisms
- Model Types:
- Model organism type (mammalian, invertebrate, cellular, in vitro) > Search first: Alliance of Genome Resources, model organism databases
- Specific model systems (mouse, rat, zebrafish, Drosophila, C. elegans, yeast, cell lines, organoids, iPSCs) > Search first: MGI, RGD, ZFIN, FlyBase, WormBase, SGD, ATCC, Cellosaurus
- Induced models (drug treatment, surgical intervention, environmental manipulation) > Search first: MGI, model organism databases, PubMed
- Genetic Models:
- Types available (knockout, knock-in, transgenic, conditional, humanized) > Search first: MGI, IMPC, KOMP, EuMMCR, IMSR
- Model Characteristics:
- Phenotype recapitulation (how well model reproduces human disease features) > Search first: Model organism databases, comparative studies, PubMed
- Model limitations (aspects of human disease not captured) > Search first: Model organism databases, PubMed, review articles
- Applications:
- Research applications (what aspects of disease can be studied) > Search first: Model organism databases, PubMed
- Resources:
- Model databases > Search first: MGI, RGD, ZFIN, FlyBase, WormBase, IMSR, EMMA, MMRRC
Citation Requirements
- Cite primary literature (PMID preferred) for all mechanistic and clinical claims
- Prioritize recent reviews and landmark papers
- Include direct quotes from abstracts where possible to support key statements
- Distinguish evidence source types: human clinical, model organism, in vitro, computational
Output Format
Structure your response as a comprehensive narrative organized by the sections above. For each section, provide: - Factual content with specific details (numbers, percentages, gene names, variant nomenclature) - Ontology term suggestions (HPO, GO, CL, UBERON, CHEBI, MAXO, MONDO) where applicable - Evidence citations with PMIDs - Direct quotes from abstracts to support key claims - Clear indication when information is not available or not applicable for this disease
This report will be used to populate a disease knowledge base entry with: - Pathophysiology descriptions with causal chains - Gene/protein annotations (HGNC, GO terms) - Phenotype associations (HP terms) with frequencies - Cell type involvement (CL terms) - Anatomical locations (UBERON terms) - Chemical entities (CHEBI terms) - Treatment annotations (MAXO terms) - Evidence items with PMIDs and exact abstract quotes - Epidemiology, prognosis, diagnostic, and prevention information - Animal model descriptions with phenotype recapitulation details
Comprehensive Research Report: Yolk Sac Tumor (YST)
Executive summary
Yolk sac tumor (YST) is a highly malignant germ cell tumor (GCT) characterized by yolk-sac (extra-embryonic endodermal) differentiation and classically associated with markedly elevated alpha‑fetoprotein (AFP) in serum and tumor tissue. It occurs most often in gonads (testis/ovary) but can arise at extragonadal sites (e.g., sacrococcygeal region, mediastinum, endometrium) and may be “germ cell–derived” or “somatically derived” (YST differentiation arising within a somatic carcinoma). Diagnostic accuracy has improved through immunohistochemical (IHC) panels (e.g., SALL4, GPC3, AFP) and newer markers such as FOXA2 in postpubertal-type YST. Recent molecular work emphasizes recurrent copy-number alterations (notably 12p gain) and subtype/site-specific copy-number patterns (e.g., 3p gains), while mutational burden is often low in pediatric GCTs.
| Item category | Specific item | Notes (e.g., postpubertal-type, patterns) | Key evidence snippet (short) | Source (authors, year, journal, DOI URL) |
|---|---|---|---|---|
| Synonym | Endodermal sinus tumor | Common synonym for yolk sac tumor, especially in ovarian literature | “yolk sac tumor (endodermal sinus tumor)” (maria2025malignantgermcells pages 2-4) | De Maria et al., 2025, Journal of Gynecologic Oncology, https://doi.org/10.3802/jgo.2025.36.e108 |
| Classification | Malignant germ cell tumor | Derived from primordial germ cells; includes gonadal and extragonadal presentations | “a highly malignant germ cell tumor” (wang2024giantovarianyolk pages 2-3, pinto2023molecularbiologyof pages 1-3) | Wang et al., 2024, Frontiers in Oncology, https://doi.org/10.3389/fonc.2024.1437728; Pinto et al., 2023, Cancers, https://doi.org/10.3390/cancers15112990 |
| Classification | WHO ovarian germ cell tumor entity | Listed as a distinct entity in WHO 2020 ovarian germ cell tumor classification | “yolk sac tumor (endodermal sinus tumor) is listed as a distinct entity in the WHO 2020 classification” (maria2025malignantgermcells pages 2-4) | De Maria et al., 2025, Journal of Gynecologic Oncology, https://doi.org/10.3802/jgo.2025.36.e108 |
| Classification | Postpubertal-type yolk sac tumor | Testicular/postpubertal context; broad histologic spectrum complicates diagnosis | “YSTpt shows a wide range of histological patterns and is challenging to diagnose” (ricci2023foxa2isa pages 19-23) | Ricci et al., 2023, Histopathology, https://doi.org/10.1111/his.14968 |
| Biomarker | Alpha-fetoprotein (AFP), serum | Core serum marker for diagnosis and monitoring; may be markedly elevated but not universally positive | “AFP is a highly specific diagnostic and monitoring marker” and “most patients have AFP >1,000 ng/mL” (cui2025aendometrialmalignant pages 2-4); “AFP was elevated in all patients (100%, 16/16)” (chen2024ultrasonographicandclinicopathological pages 3-5) | Cui et al., 2025, Frontiers in Oncology, https://doi.org/10.3389/fonc.2025.1551266; Chen et al., 2024, Frontiers in Oncology, https://doi.org/10.3389/fonc.2024.1417761 |
| Biomarker | AFP, immunohistochemistry | Often positive, but can be focal/weak or occasionally negative compared with other markers | “AFP is often only focal and weak or absent” in some YSTpt patterns (ricci2023foxa2isa pages 19-23) | Ricci et al., 2023, Histopathology, https://doi.org/10.1111/his.14968 |
| Biomarker | Glypican-3 (GPC3) | Sensitive YST IHC marker; may outperform AFP in sensitivity | “GPC-3 is a sensitive YST marker and can outperform AFP” (cui2025aendometrialmalignant pages 4-6); “roughly threefold higher sensitivity than AFP” (wang2024giantovarianyolk pages 2-3) | Cui et al., 2025, Frontiers in Oncology, https://doi.org/10.3389/fonc.2025.1551266; Wang et al., 2024, Frontiers in Oncology, https://doi.org/10.3389/fonc.2024.1437728 |
| Biomarker | SALL4 | Sensitive germ cell marker; useful in differential diagnosis | “SALL4 is expressed in all germ cell tumors except choriocarcinoma” and recommended in combined panels (cui2025aendometrialmalignant pages 4-6) | Cui et al., 2025, Frontiers in Oncology, https://doi.org/10.3389/fonc.2025.1551266 |
| Biomarker | FOXA2 | Reliable nuclear marker for postpubertal-type YST across patterns | “FOXA2 gives a clear, easily interpretable nuclear signal” with “diffuse and strong stain” (ricci2023foxa2isa pages 19-23) | Ricci et al., 2023, Histopathology, https://doi.org/10.1111/his.14968 |
| Biomarker | OCT3/4 negativity | Helpful exclusion marker against embryonal carcinoma in ovarian YST workup | “OCT3/4 negativity helping exclude embryonal carcinoma” (brock2026yolksactumor pages 5-6) | Brock et al., 2026, GSC Advanced Research and Reviews, https://doi.org/10.30574/gscarr.2026.26.1.0023 |
| Biomarker | Combined IHC panel: AFP + GPC3 + SALL4 | Best used with morphology; at least 2 markers can strengthen diagnosis | “combined IHC (≥2 markers among SALL4, GPC-3, AFP) plus morphology is recommended” (cui2025aendometrialmalignant pages 4-6) | Cui et al., 2025, Frontiers in Oncology, https://doi.org/10.3389/fonc.2025.1551266 |
| Classification | Histologic hallmarks | Classic patterns include reticular/microcystic growth and Schiller–Duval bodies | “characteristic Schiller–Duval bodies” (wang2024giantovarianyolk pages 2-3); “reticular pattern, Schiller-Duval bodies” (cui2025aendometrialmalignant pages 4-6) | Wang et al., 2024, Frontiers in Oncology, https://doi.org/10.3389/fonc.2024.1437728; Cui et al., 2025, Frontiers in Oncology, https://doi.org/10.3389/fonc.2025.1551266 |
| Classification | Polyvesicular-vitelline (PVV) pattern | Uncommon ovarian YST variant; can mimic benign cystic lesions | “PVV histologic pattern occurs in roughly 25%” and may lack Schiller-Duval bodies (brock2026yolksactumor pages 5-6, brock2026yolksactumor pages 6-8) | Brock et al., 2026, GSC Advanced Research and Reviews, https://doi.org/10.30574/gscarr.2026.26.1.0023 |
Table: This table summarizes key synonyms, classification descriptors, and the most clinically useful serum and immunohistochemical biomarkers for yolk sac tumor. It is useful for building a disease knowledge base entry and for rapid diagnostic reference.
1. Disease information
1.1 What is the disease?
YST (also called endodermal sinus tumor) is a malignant germ cell tumor with yolk-sac differentiation; in ovarian literature it is typically grouped among malignant ovarian germ cell tumors (MOGCTs) and is recognized as a distinct entity in WHO classification schemes. (maria2025malignantgermcells pages 2-4, wang2024giantovarianyolk pages 2-3)
Synonyms / alternative names - Yolk sac tumor (YST) (maria2025malignantgermcells pages 2-4) - Endodermal sinus tumor (maria2025malignantgermcells pages 2-4) - “Ovarian yolk sac tumor” (OYST) for ovarian presentations (wang2024giantovarianyolk pages 2-3)
1.2 Key identifiers (ontology / coding)
Not fully retrievable with the current tool context. The current retrieved literature does not provide explicit MONDO, MeSH, ICD‑10/ICD‑11, OMIM, or Orphanet IDs for YST. Therefore: - MONDO ID: Not available from retrieved sources. - MeSH/ICD/Orphanet/OMIM: Not available from retrieved sources.
1.3 Data source type
The evidence assembled here is predominantly aggregated disease-level resources (reviews, retrospective cohorts, and trial registry entries) plus case reports illustrating rare anatomic sites and somatic derivation. (pinto2023molecularbiologyof pages 1-3, chen2024ultrasonographicandclinicopathological pages 1-2, NCT06341998 chunk 1)
2. Etiology
2.1 Disease causal factors (current understanding)
YST is understood as arising from aberrant transformation of primordial germ cells (PGCs) during development, with germ cell tumors reflecting arrested/aberrant PGC development and migration. (pinto2023molecularbiologyof pages 1-3)
A clinically important etiologic nuance is that YST-like differentiation can also occur within somatic carcinomas (somatic derivation), particularly in older patients and in endometrial tumors, complicating classification and management. (cui2025aendometrialmalignant pages 4-6, cui2025aendometrialmalignant pages 2-4)
2.2 Risk factors / protective factors
Limited disease-specific epidemiologic risk-factor data were available in the retrieved sources. However, several consistent clinical associations (not “risk factors” per se) emerge: - Predominant occurrence in children/adolescents/young adults for ovarian/pelvic YST (mean ages in cohorts and reviews in the 20s; most <30). (chen2024ultrasonographicandclinicopathological pages 2-3, brock2026yolksactumor pages 5-6) - In endometrial YST series, older age is common for mixed/somatic-derived cases and is associated with worse outcomes (age >50 associated with higher mortality in one literature review). (cui2025aendometrialmalignant pages 4-6)
No clear protective factors or gene–environment interactions were identified in the retrieved sources.
3. Phenotypes (clinical presentation)
3.1 Common phenotypes and suggested HPO terms
Phenotypes vary by anatomic site; below are common patterns supported by recent cohort data.
A. Ovarian/pelvic YST in women (Frontiers in Oncology 2024 retrospective cohort, n=16) - Abdominal/pelvic pain (14/16; 87.5%). Suggested HPO: HP:0002027 Abdominal pain. (chen2024ultrasonographicandclinicopathological pages 3-5, chen2024ultrasonographicandclinicopathological pages 2-3) - Pelvic/abdominal mass. Suggested HPO: HP:0100542 Pelvic mass (or HP:0031166 Abdominal mass). (maria2025malignantgermcells pages 2-4) - Laboratory abnormality: elevated serum AFP in essentially all cases in this cohort (16/16; 100%). Suggested HPO: HP:0040215 Elevated circulating alpha-fetoprotein. (chen2024ultrasonographicandclinicopathological pages 3-5, chen2024ultrasonographicandclinicopathological pages 2-3) - Ascites (reported in subset). Suggested HPO: HP:0001541 Ascites. (chen2024ultrasonographicandclinicopathological pages 7-9)
B. Pediatric testicular YST - Testicular/scrotal mass. Suggested HPO: HP:0000023 Scrotal mass or HP:0000035 Testicular tumor/mass. (yu2024nomogramforpredicting pages 2-3) - Elevated AFP is highly prevalent but not universal (e.g., 27/29 elevated in one 2024 cohort). Suggested HPO: HP:0040215 Elevated circulating alpha-fetoprotein. (yu2024nomogramforpredicting pages 2-3, yu2024nomogramforpredicting pages 5-6)
C. Endometrial YST (rare, often mixed/somatic-derived) - Irregular vaginal bleeding / postmenopausal bleeding. Suggested HPO: HP:0000140 Abnormal uterine bleeding. (cui2025aendometrialmalignant pages 4-6)
3.2 Onset, severity, progression
- Ovarian/pelvic YST predominantly affects children and young women (e.g., 68.75% <30 in one pelvic cohort), often presenting with symptomatic pain and large masses, implying relatively rapid growth and clinically apparent disease. (chen2024ultrasonographicandclinicopathological pages 2-3, maria2025malignantgermcells pages 2-4)
- Pediatric testicular YST tends to present in very young children (median 14 months in one cohort), supporting very early onset in that presentation. (yu2024nomogramforpredicting pages 2-3)
Quality-of-life measures (EQ‑5D/SF‑36/PROMIS) were not available in the retrieved sources.
4. Genetic / molecular information
4.1 Causal genes
YST is not a Mendelian single-gene disorder; “causal genes” in the inherited-disease sense are not established in the retrieved sources. Molecular drivers are primarily somatic and chromosomal.
4.2 Chromosomal abnormalities and copy-number alterations (key recent findings)
12p gain / 12p abnormalities - Recurrent 12p gain is a hallmark across germ cell tumors, including ovarian malignant GCTs; pediatric series summarized in a 2023 review report 12p gain in 44% (15/34) of malignant GCTs and in 10/14 tumors in patients <15, with 4/14 YSTs in children <5 showing 12p gains. (pinto2023molecularbiologyof pages 7-9) - A 2025 ovarian GCT review notes that YST is a WHO-recognized entity and emphasizes tumor markers rather than genomics, but the broader 2023 clinical challenges review reports that many YSTs show 12p gains plus additional gains/losses. (maria2025malignantgermcells pages 2-4, saani2023clinicalchallengesin pages 9-10)
3p25.3 gain as a prognostic marker in CNS GCTs with YST components (Scientific Reports 2023) - In a cohort of 81 CNS GCTs, 3p25.3 gain occurred in 5/81 (6.2%), exclusively among non-germinomatous GCTs (5/40; 12.5%; p=0.03). (takami2023distinctpatternsof pages 1-2) - Among NGGCTs, presence of a YST component was associated with a higher frequency of 3p25.3 gain (18.2% with YST component vs 1.5% without; p=0.048). (takami2023distinctpatternsof pages 1-2) - 3p25.3 gain was associated with significantly shorter progression-free survival (p=0.047), suggesting a potential risk-stratification biomarker (with the caveat of small sample sizes and need for validation). (takami2023distinctpatternsof pages 3-4, takami2023distinctpatternsof pages 6-7)
4.3 Somatic mutations / mutational burden / MSI/TMB
- Pediatric ovarian GCTs are described as having generally lower mutational burden than adult tumors, with epigenetic and copy-number alterations emphasized. (pinto2023molecularbiologyof pages 7-9)
- In a mixed endometrial carcinoma with YST differentiation (somatic derivation), targeted sequencing identified TP53 C275Y (VAF 17.5%), microsatellite stable status, and low TMB (3.110 mutations/Mb), illustrating that somatically derived YST differentiation can occur in a genomically “carcinoma-like” context rather than classic germ-cell genomics. (cui2025aendometrialmalignant pages 2-4)
4.4 Epigenetics and microRNAs (recent synthesis)
A 2023 molecular review of ovarian GCTs highlights: - Imprinting/methylation abnormalities (e.g., involving H19 and IGF2) in pediatric germ cell tumors and histology-specific methylation signatures that may reflect the PGC developmental stage at transformation. (pinto2023molecularbiologyof pages 18-19, pinto2023molecularbiologyof pages 12-13) - Consistent dysregulation of circulating and tumor miRNAs, particularly miR‑371a‑3p, with reported sensitivity 84.7% and specificity 99% for GCT detection in the cited synthesis, and decline after tumor resection—supporting real-world biomarker application. (pinto2023molecularbiologyof pages 12-13)
4.5 Suggested ontology terms (molecular)
- GO biological process (examples):
- GO:0007281 germ cell development (fits PGC transformation paradigm) (pinto2023molecularbiologyof pages 1-3)
- GO:0006306 DNA methylation (epigenetic emphasis) (pinto2023molecularbiologyof pages 12-13)
- Cell Ontology (CL) (examples):
- CL:0000670 primordial germ cell (conceptual cell of origin) (pinto2023molecularbiologyof pages 1-3)
5. Environmental information
No specific environmental toxins, lifestyle factors, or infectious agents were identified as causal or modifying factors in the retrieved sources for YST.
6. Mechanism / pathophysiology
6.1 Conceptual causal chain
1) Initiating event: aberrant transformation/arrest of PGC development (germ-cell–derived YST) or aberrant somatic differentiation in carcinoma (somatic-derived YST component). (pinto2023molecularbiologyof pages 1-3, cui2025aendometrialmalignant pages 4-6) 2) Molecular landscape: predominant chromosomal/copy-number alterations (e.g., 12p gain; subtype/site-specific gains/losses such as 3p gains) with relatively low somatic mutation burden in many pediatric cases. (pinto2023molecularbiologyof pages 7-9, saani2023clinicalchallengesin pages 9-10) 3) Tumor differentiation program: yolk-sac/endodermal differentiation reflected by expression of AFP and endodermal-associated markers (e.g., GPC3, SALL4; FOXA2 in postpubertal-type). (ricci2023foxa2isa pages 19-23, cui2025aendometrialmalignant pages 4-6) 4) Clinical manifestations: rapidly enlarging masses (ovary/testis/extragonadal) causing pain or bleeding, and high serum AFP providing a measurable tumor burden proxy. (chen2024ultrasonographicandclinicopathological pages 3-5, cui2025aendometrialmalignant pages 4-6)
6.2 Pathology and key diagnostic histologic features
- Schiller–Duval bodies are classic features in many YSTs. (wang2024giantovarianyolk pages 2-3)
- Broad morphologic spectrum can create diagnostic pitfalls; reticular/microcystic and other patterns occur, and polyvesicular‑vitelline patterns may lack Schiller–Duval bodies and mimic benign lesions. (cui2025aendometrialmalignant pages 4-6, brock2026yolksactumor pages 5-6)
7. Anatomical structures affected
7.1 Organ and site distribution (examples from recent cohorts)
- Pelvic YST in women (n=16): ovary (13/16; 81.25%), sacrococcygeal region (2/16; 12.5%), mesentery (1/16; 6.25%). (chen2024ultrasonographicandclinicopathological pages 3-5, chen2024ultrasonographicandclinicopathological pages 1-2)
7.2 Suggested UBERON terms (examples)
- Ovary: UBERON:0000992 (supported by ovarian predominance in pelvic cohort). (chen2024ultrasonographicandclinicopathological pages 3-5)
- Testis: UBERON:0000473 (pediatric testicular YST cohorts). (yu2024nomogramforpredicting pages 2-3)
- Sacrococcygeal region (approximate): UBERON:0001474 Coccyx / adjacent pelvic region (site reported in cohort). (chen2024ultrasonographicandclinicopathological pages 3-5)
8. Temporal development
8.1 Onset patterns
- Pediatric testicular YST: very early childhood presentation (median ~14 months in one cohort). (yu2024nomogramforpredicting pages 2-3)
- Ovarian/pelvic YST: predominantly in young women but can occur across a wide age range (1–72 years in a pelvic cohort). (chen2024ultrasonographicandclinicopathological pages 2-3)
8.2 Staging and progression
Formal unified staging across all YST sites is not captured in the retrieved sources; ovarian YST typically uses FIGO staging (not fully detailed in retrieved evidence). However, endometrial YST literature review data show many cases presenting beyond stage I and that pure YSTs present earlier than mixed tumors in that site-specific literature. (cui2025aendometrialmalignant pages 4-6)
9. Inheritance and population
YST is not described in the retrieved sources as an inherited Mendelian disorder (no AD/AR/X-linked pattern reported). Population-level incidence statistics were limited: - A 2025 ovarian malignant GCT review gives age-specific incidence estimates for malignant ovarian GCTs overall (not YST-specific): ≈5.7 per million at age 14 and ≈27 per million at ages 15–19. (maria2025malignantgermcells pages 2-4)
Robust global prevalence/incidence estimates specifically for YST (per 100,000) were not available from retrieved sources.
10. Diagnostics
10.1 Core biomarkers (serum)
- AFP is the central serum biomarker for YST diagnosis and monitoring; in pelvic YST cohort data AFP was elevated in 100% (16/16). (chen2024ultrasonographicandclinicopathological pages 3-5)
- AFP is highly informative but not perfectly sensitive: in a 2024 pediatric testicular cohort, 27/29 (93.1%) YST had elevated AFP, and 3 YST cases had normal AFP in the same study’s narrative discussion. (yu2024nomogramforpredicting pages 2-3, yu2024nomogramforpredicting pages 5-6)
10.2 Pathology and IHC panels (key recent developments)
YST diagnosis relies on morphology plus IHC markers; commonly used markers include AFP, GPC3, SALL4, and additional markers to exclude mimics (e.g., OCT3/4 negative helps exclude embryonal carcinoma). (cui2025aendometrialmalignant pages 4-6, brock2026yolksactumor pages 5-6)
FOXA2 as a 2023 diagnostic advance (postpubertal-type YST): - In a Histopathology 2023 study, FOXA2 is described as giving a clear nuclear signal with “complete absence of background reactivity” and “diffuse and strong stain” across multiple YST patterns where AFP may be “focal and weak” or absent, supporting FOXA2 as a reliable marker for YSTpt diagnosis. (ricci2023foxa2isa pages 19-23, ricci2023foxa2isa media d654aa6d)
10.3 Imaging and real-world implementation (2024 quantitative studies)
Pediatric testicular YST (Frontiers in Pediatrics 2024 nomogram, n=119; 29 YST): - Age and ultrasound features plus AFP improve preoperative discrimination: elevated AFP in 93.1% (27/29) vs 2.2% (2/90) benign; strong Doppler blood-flow signals in 93.1% vs 5.6% benign. (yu2024nomogramforpredicting pages 2-3) - Combined model (age + AFP + ultrasound blood flow) achieved AUC 0.984, sensitivity 0.978, and specificity ≈0.966, with reported accuracy ≈0.98. (yu2024nomogramforpredicting pages 2-3)
Pediatric testicular YST (World Journal of Surgical Oncology 2024 MRI study, n=80; 40 YST): - MRI “signal intensity” achieved AUC 0.936 (95% CI 0.877–0.995) for discriminating YST; “bright dot sign” present in 57.5% and spermatic cord thickening in 95%. (zheng2024diagnosticfeaturesof pages 1-3, zheng2024diagnosticfeaturesof pages 3-5)
Pelvic YST in women (Frontiers in Oncology 2024, n=16): - Ultrasound patterns: cystic (12.5%), mixed (25%), solid (62.5%), often with rich vascularity and low–moderate resistance indices (RI 0.21–0.63). (chen2024ultrasonographicandclinicopathological pages 3-5, chen2024ultrasonographicandclinicopathological pages 7-9)
10.4 Differential diagnosis (examples)
- Ovarian clear cell carcinoma can be a key mimic; SALL4 (and broader germ cell marker panels) can help distinguish YST from clear cell adenocarcinoma. (wang2024giantovarianyolk pages 2-3)
11. Outcome / prognosis
11.1 Survival statistics
Survival varies strongly by site and stage; robust population-level YST survival was not available in the retrieved cohort papers, but ovarian YST literature summarized in a 2026 review reports: - 5‑year survival approximately 75–100% for stage I and 63–75% for stages II–IV with BEP-based treatment, in the cited series-level summaries. (brock2026yolksactumor pages 5-6)
11.2 Prognostic biomarkers / factors
- In CNS NGGCTs, 3p25.3 gain was associated with YST components and shorter PFS (p=0.047), suggesting prognostic stratification potential. (takami2023distinctpatternsof pages 1-2, takami2023distinctpatternsof pages 3-4)
- In endometrial YST literature review data, older age (>50) associated with higher mortality and mixed tumors tended to occur in older patients. (cui2025aendometrialmalignant pages 4-6)
12. Treatment
12.1 Standard of care (real-world implementation)
Surgery + platinum-based chemotherapy - Ovarian YST: standard management is surgical resection (often fertility-sparing in young patients when appropriate) followed by BEP chemotherapy (bleomycin, etoposide, cisplatin). (brock2026yolksactumor pages 5-6, brock2026yolksactumor pages 3-5) - A 2026 ovarian YST case report shows AFP normalization after BEP cycle 2 and durable 3‑year remission after fertility-sparing surgery plus BEP. (brock2026yolksactumor pages 3-5)
MAXO term suggestions (examples) - Surgical tumor resection / oophorectomy: MAXO:0000004 Surgical procedure (site-specific refinements needed) - Platinum-based combination chemotherapy: MAXO:0000058 Chemotherapy
12.2 Treatment in rare sites / somatic-derived YST
- Endometrial tumors with YST components: therapy is heterogeneous; one reported approach includes surgery + BEP, with recurrence prompting consideration of other systemic regimens including immune checkpoint inhibitor use in a case context. (cui2025aendometrialmalignant pages 2-4)
12.3 Clinical trials (recent registry evidence; pediatric recurrent/refractory YST)
Two ClinicalTrials.gov studies explicitly targeted relapsed/refractory YST in children (both completed; results not available in retrieved registry excerpts):
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NCT06341998 (ClinicalTrials.gov; primary completion 2024‑01‑01; URL: https://clinicaltrials.gov/study/NCT06341998): sirolimus + TIC (nab‑paclitaxel, ifosfamide, carboplatin) “S‑TIC” regimen for recurrent/refractory extracranial YST in children (≤18 years); Simon two-stage design; primary endpoint ORR; secondary endpoints PFS/OS/safety; AFP monitored each cycle. (NCT06341998 chunk 1)
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NCT06470464 (ClinicalTrials.gov; completed; URL: https://clinicaltrials.gov/study/NCT06470464): thalidomide + TGA (nab‑paclitaxel, gemcitabine, epirubicin) for repeatedly relapsed/refractory pediatric YST; primary endpoint ORR (RECIST 1.1 plus AFP reduction ≥90%). (NCT06470464 chunk 1)
13. Prevention
No primary prevention strategies specific to YST were identified in the retrieved sources. Secondary prevention is generally limited to early detection of masses and prompt diagnostic evaluation with imaging plus AFP (and appropriate interpretation of AFP in infancy). (yu2024nomogramforpredicting pages 2-3)
14. Other species / natural disease
No naturally occurring YST data in non-human species were retrieved in the current evidence set.
15. Model organisms / model systems
The retrieved sources indicate active development of in vitro and in vivo models for ovarian GCTs (including YST) but do not provide concrete model organism IDs or specific cell line names within the available excerpts. (pinto2023molecularbiologyof pages 1-3)
Expert opinion / authoritative synthesis (what experts emphasize)
- Diagnostic certainty requires morphology + IHC panels: multiple sources emphasize that AFP alone is not sufficient (can be focal/weak or rarely negative in tissue; serum AFP can be non-specific in infants), and that combined markers (SALL4, GPC3, AFP) plus morphology improve reliability. (ricci2023foxa2isa pages 19-23, cui2025aendometrialmalignant pages 4-6, yu2024nomogramforpredicting pages 5-6)
- FOXA2 is emerging as a high-value marker for postpubertal-type YST because it can be diffusely positive where AFP is not, with clean nuclear staining and minimal background—useful in challenging patterns and small biopsies. (ricci2023foxa2isa pages 19-23)
- Risk stratification may increasingly use genomic copy-number features (e.g., 12p and 3p25.3 gains), particularly in CNS NGGCTs, but validation is needed before routine clinical application. (takami2023distinctpatternsof pages 1-2, takami2023distinctpatternsof pages 6-7)
Key gaps / limitations of this report
- Formal ontology identifiers (MONDO/MeSH/ICD/Orphanet/OMIM) could not be extracted from the retrieved evidence set and would require targeted database queries beyond the current retrieved texts.
- Large 2023–2024 genomic cohort studies specific to YST (with mutation frequencies by site and validated epigenetic signatures) were not fully available in the retrieved corpus; conclusions about genetics therefore emphasize copy-number trends and review-level synthesis.
- Trial registry excerpts did not include outcome results; therefore efficacy conclusions for NCT06341998 and NCT06470464 cannot be drawn here.
References
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(chen2024ultrasonographicandclinicopathological pages 3-5): Mei Chen, Shengmin Zhang, Xiupeng Jia, Youfeng Xu, Yaping Wei, and Shusheng Liao. Ultrasonographic and clinicopathological features of pelvic yolk sac tumors in women: a single-center retrospective analysis. Frontiers in Oncology, Jun 2024. URL: https://doi.org/10.3389/fonc.2024.1417761, doi:10.3389/fonc.2024.1417761. This article has 5 citations.
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(cui2025aendometrialmalignant pages 4-6): Zicheng Cui, Yuping Shan, Huijun Chu, and Aiping Chen. A endometrial malignant tumor with yolk sac tumor component: a case report and literature review. Frontiers in Oncology, Sep 2025. URL: https://doi.org/10.3389/fonc.2025.1551266, doi:10.3389/fonc.2025.1551266. This article has 0 citations.
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(brock2026yolksactumor pages 5-6): Anna Claire Brock, Kassandra Piris, Jennifer C Ejeh, Sara Naser, Elizabeth Sánchez, Idanys Albanes, Jessica Jahoda, and Mohamed Aziz. Yolk sac tumor of the ovary with polyvesicular-vitelline pattern: case report of an uncommon tumor and a brief review of the literature. GSC Advanced Research and Reviews, 26:209-216, Jan 2026. URL: https://doi.org/10.30574/gscarr.2026.26.1.0023, doi:10.30574/gscarr.2026.26.1.0023. This article has 0 citations.
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(brock2026yolksactumor pages 6-8): Anna Claire Brock, Kassandra Piris, Jennifer C Ejeh, Sara Naser, Elizabeth Sánchez, Idanys Albanes, Jessica Jahoda, and Mohamed Aziz. Yolk sac tumor of the ovary with polyvesicular-vitelline pattern: case report of an uncommon tumor and a brief review of the literature. GSC Advanced Research and Reviews, 26:209-216, Jan 2026. URL: https://doi.org/10.30574/gscarr.2026.26.1.0023, doi:10.30574/gscarr.2026.26.1.0023. This article has 0 citations.
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(chen2024ultrasonographicandclinicopathological pages 1-2): Mei Chen, Shengmin Zhang, Xiupeng Jia, Youfeng Xu, Yaping Wei, and Shusheng Liao. Ultrasonographic and clinicopathological features of pelvic yolk sac tumors in women: a single-center retrospective analysis. Frontiers in Oncology, Jun 2024. URL: https://doi.org/10.3389/fonc.2024.1417761, doi:10.3389/fonc.2024.1417761. This article has 5 citations.
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(NCT06341998 chunk 1): Clinical Study of Chemotherapy in the Treatment of Recurrent/Refractory Yolk Sac Tumor in Children. Shandong First Medical University. 2020. ClinicalTrials.gov Identifier: NCT06341998
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(chen2024ultrasonographicandclinicopathological pages 2-3): Mei Chen, Shengmin Zhang, Xiupeng Jia, Youfeng Xu, Yaping Wei, and Shusheng Liao. Ultrasonographic and clinicopathological features of pelvic yolk sac tumors in women: a single-center retrospective analysis. Frontiers in Oncology, Jun 2024. URL: https://doi.org/10.3389/fonc.2024.1417761, doi:10.3389/fonc.2024.1417761. This article has 5 citations.
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(chen2024ultrasonographicandclinicopathological pages 7-9): Mei Chen, Shengmin Zhang, Xiupeng Jia, Youfeng Xu, Yaping Wei, and Shusheng Liao. Ultrasonographic and clinicopathological features of pelvic yolk sac tumors in women: a single-center retrospective analysis. Frontiers in Oncology, Jun 2024. URL: https://doi.org/10.3389/fonc.2024.1417761, doi:10.3389/fonc.2024.1417761. This article has 5 citations.
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(yu2024nomogramforpredicting pages 2-3): Huan Yu, Hui Wang, Yi-Chen Huang, Huiyong Hu, Yue Zhang, Min Wu, Yiqing Lyu, Yan Chen, Lijun Zhou, Yan Liang, Huizhen Sun, Xiaoling Lin, Hua Xie, and Fang Chen. Nomogram for predicting testicular yolk sac tumor in children based on age, alpha-fetoprotein, and ultrasonography. Frontiers in Pediatrics, Nov 2024. URL: https://doi.org/10.3389/fped.2024.1407120, doi:10.3389/fped.2024.1407120. This article has 3 citations.
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(yu2024nomogramforpredicting pages 5-6): Huan Yu, Hui Wang, Yi-Chen Huang, Huiyong Hu, Yue Zhang, Min Wu, Yiqing Lyu, Yan Chen, Lijun Zhou, Yan Liang, Huizhen Sun, Xiaoling Lin, Hua Xie, and Fang Chen. Nomogram for predicting testicular yolk sac tumor in children based on age, alpha-fetoprotein, and ultrasonography. Frontiers in Pediatrics, Nov 2024. URL: https://doi.org/10.3389/fped.2024.1407120, doi:10.3389/fped.2024.1407120. This article has 3 citations.
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(pinto2023molecularbiologyof pages 7-9): Mariana Tomazini Pinto, Gisele Eiras Martins, Ana Glenda Santarosa Vieira, Janaina Mello Soares Galvão, Cristiano de Pádua Souza, Carla Renata Pacheco Donato Macedo, and Luiz Fernando Lopes. Molecular biology of pediatric and adult ovarian germ cell tumors: a review. Cancers, 15:2990, May 2023. URL: https://doi.org/10.3390/cancers15112990, doi:10.3390/cancers15112990. This article has 21 citations.
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(saani2023clinicalchallengesin pages 9-10): Iqra Saani, Nitish Raj, Raja Sood, Shahbaz Ansari, Haider Abbas Mandviwala, Elisabet Sanchez, and Stergios Boussios. Clinical challenges in the management of malignant ovarian germ cell tumours. International Journal of Environmental Research and Public Health, 20:6089, Jun 2023. URL: https://doi.org/10.3390/ijerph20126089, doi:10.3390/ijerph20126089. This article has 85 citations.
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(takami2023distinctpatternsof pages 1-2): Hirokazu Takami, Kaishi Satomi, Kohei Fukuoka, Taishi Nakamura, Shota Tanaka, Akitake Mukasa, Nobuhito Saito, Tomonari Suzuki, Takaaki Yanagisawa, Kazuhiko Sugiyama, Masayuki Kanamori, Toshihiro Kumabe, Teiji Tominaga, Kaoru Tamura, Taketoshi Maehara, Masahiro Nonaka, Akio Asai, Kiyotaka Yokogami, Hideo Takeshima, Toshihiko Iuchi, Keiichi Kobayashi, Koji Yoshimoto, Keiichi Sakai, Yoichi Nakazato, Masao Matsutani, Motoo Nagane, Ryo Nishikawa, and Koichi Ichimura. Distinct patterns of copy number alterations may predict poor outcome in central nervous system germ cell tumors. Scientific Reports, Sep 2023. URL: https://doi.org/10.1038/s41598-023-42842-3, doi:10.1038/s41598-023-42842-3. This article has 11 citations and is from a peer-reviewed journal.
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(takami2023distinctpatternsof pages 3-4): Hirokazu Takami, Kaishi Satomi, Kohei Fukuoka, Taishi Nakamura, Shota Tanaka, Akitake Mukasa, Nobuhito Saito, Tomonari Suzuki, Takaaki Yanagisawa, Kazuhiko Sugiyama, Masayuki Kanamori, Toshihiro Kumabe, Teiji Tominaga, Kaoru Tamura, Taketoshi Maehara, Masahiro Nonaka, Akio Asai, Kiyotaka Yokogami, Hideo Takeshima, Toshihiko Iuchi, Keiichi Kobayashi, Koji Yoshimoto, Keiichi Sakai, Yoichi Nakazato, Masao Matsutani, Motoo Nagane, Ryo Nishikawa, and Koichi Ichimura. Distinct patterns of copy number alterations may predict poor outcome in central nervous system germ cell tumors. Scientific Reports, Sep 2023. URL: https://doi.org/10.1038/s41598-023-42842-3, doi:10.1038/s41598-023-42842-3. This article has 11 citations and is from a peer-reviewed journal.
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(takami2023distinctpatternsof pages 6-7): Hirokazu Takami, Kaishi Satomi, Kohei Fukuoka, Taishi Nakamura, Shota Tanaka, Akitake Mukasa, Nobuhito Saito, Tomonari Suzuki, Takaaki Yanagisawa, Kazuhiko Sugiyama, Masayuki Kanamori, Toshihiro Kumabe, Teiji Tominaga, Kaoru Tamura, Taketoshi Maehara, Masahiro Nonaka, Akio Asai, Kiyotaka Yokogami, Hideo Takeshima, Toshihiko Iuchi, Keiichi Kobayashi, Koji Yoshimoto, Keiichi Sakai, Yoichi Nakazato, Masao Matsutani, Motoo Nagane, Ryo Nishikawa, and Koichi Ichimura. Distinct patterns of copy number alterations may predict poor outcome in central nervous system germ cell tumors. Scientific Reports, Sep 2023. URL: https://doi.org/10.1038/s41598-023-42842-3, doi:10.1038/s41598-023-42842-3. This article has 11 citations and is from a peer-reviewed journal.
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(pinto2023molecularbiologyof pages 18-19): Mariana Tomazini Pinto, Gisele Eiras Martins, Ana Glenda Santarosa Vieira, Janaina Mello Soares Galvão, Cristiano de Pádua Souza, Carla Renata Pacheco Donato Macedo, and Luiz Fernando Lopes. Molecular biology of pediatric and adult ovarian germ cell tumors: a review. Cancers, 15:2990, May 2023. URL: https://doi.org/10.3390/cancers15112990, doi:10.3390/cancers15112990. This article has 21 citations.
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(pinto2023molecularbiologyof pages 12-13): Mariana Tomazini Pinto, Gisele Eiras Martins, Ana Glenda Santarosa Vieira, Janaina Mello Soares Galvão, Cristiano de Pádua Souza, Carla Renata Pacheco Donato Macedo, and Luiz Fernando Lopes. Molecular biology of pediatric and adult ovarian germ cell tumors: a review. Cancers, 15:2990, May 2023. URL: https://doi.org/10.3390/cancers15112990, doi:10.3390/cancers15112990. This article has 21 citations.
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(ricci2023foxa2isa media d654aa6d): Costantino Ricci, Francesca Ambrosi, Tania Franceschini, Francesca Giunchi, Giorgia Di Filippo, Eugenia Franchini, Francesco Massari, Veronica Mollica, Valentina Tateo, Federico Mineo Bianchi, Maurizio Colecchia, Andres Martin Acosta, and Michelangelo Fiorentino. Foxa2 is a reliable marker for the diagnosis of yolk sac tumour postpubertal‐type. Histopathology, 83:465-476, Jun 2023. URL: https://doi.org/10.1111/his.14968, doi:10.1111/his.14968. This article has 23 citations and is from a domain leading peer-reviewed journal.
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(zheng2024diagnosticfeaturesof pages 1-3): Xiaoli Zheng, Siqi Zhang, Taiya Chen, Huan Zhang, Shoulin Li, Hongwu Zeng, and Wenhong Ye. Diagnostic features of pediatric testicular yolk sac tumors: a 13-year retrospective analysis. World Journal of Surgical Oncology, Dec 2024. URL: https://doi.org/10.1186/s12957-024-03611-2, doi:10.1186/s12957-024-03611-2. This article has 4 citations and is from a peer-reviewed journal.
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(zheng2024diagnosticfeaturesof pages 3-5): Xiaoli Zheng, Siqi Zhang, Taiya Chen, Huan Zhang, Shoulin Li, Hongwu Zeng, and Wenhong Ye. Diagnostic features of pediatric testicular yolk sac tumors: a 13-year retrospective analysis. World Journal of Surgical Oncology, Dec 2024. URL: https://doi.org/10.1186/s12957-024-03611-2, doi:10.1186/s12957-024-03611-2. This article has 4 citations and is from a peer-reviewed journal.
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(brock2026yolksactumor pages 3-5): Anna Claire Brock, Kassandra Piris, Jennifer C Ejeh, Sara Naser, Elizabeth Sánchez, Idanys Albanes, Jessica Jahoda, and Mohamed Aziz. Yolk sac tumor of the ovary with polyvesicular-vitelline pattern: case report of an uncommon tumor and a brief review of the literature. GSC Advanced Research and Reviews, 26:209-216, Jan 2026. URL: https://doi.org/10.30574/gscarr.2026.26.1.0023, doi:10.30574/gscarr.2026.26.1.0023. This article has 0 citations.
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(NCT06470464 chunk 1): Thalidomide Combined With Chemotherapy in the Treatment of Relapsed or Refractory Yolk Sac Tumor. Shandong First Medical University. 2021. ClinicalTrials.gov Identifier: NCT06470464
