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name: Melanoma_in_Congenital_Melanocytic_Nevus
creation_date: '2025-12-04T16:57:31Z'
updated_date: '2026-04-22T20:13:21Z'
category: Skin Cancer
parents:
- Congenital Melanocytic Nevus
- Melanoma
prevalence:
- population: General Population
percentage: Rare
evidence:
- reference: PMID:26618123
reference_title: "Analysis of the Clinical and Histopathological Patterns of 100 Consecutive Cases of Primary Cutaneous Melanoma and Correlation with Staging."
supports: PARTIAL
snippet: Acral lentiginous melanoma occurred most frequently ... Corresponding to previous findings, nodular melanoma tended to occur at a higher stage than other types.
explanation: This study discusses the epidemiology of cutaneous melanoma in Korea, showing the clinical and histopathological patterns of primary cutaneous melanoma.
- reference: PMID:17377384
reference_title: "Congenital melanocytic nevus: an epidemiologic study in Italy."
supports: PARTIAL
snippet: The observations of this study also suggest that the risk of appearance of MM, at least in childhood and adolescence, is limited for medium-sized CMN.
explanation: This reference suggests that the risk of melanoma (MM) from medium-sized congenital melanocytic nevi (CMN) is limited in childhood and adolescence, but does not provide a specific prevalence percentage.
- reference: PMID:19880040
reference_title: "Childhood melanoma."
supports: PARTIAL
snippet: Some risk factors for melanoma include xeroderma pigmentosum, giant congenital melanocytic nevi, dysplastic nevus syndrome, atypical nevi, many acquired melanocytic nevi, family history of melanoma, and immunosuppression.
explanation: While this source lists giant congenital melanocytic nevi as a risk factor, it does not directly address the prevalence of melanoma in these nevi.
- reference: PMID:35561684
reference_title: "Topical therapy for regression and melanoma prevention of congenital giant nevi."
supports: PARTIAL
snippet: Their most dangerous consequence is progression to melanoma. This risk often triggers preemptive extensive surgical excisions in childhood, producing severe lifelong challenges.
explanation: The reference acknowledges the high risk of melanoma progression in giant congenital melanocytic nevi but does not quantify the prevalence in the general population.
- reference: PMID:36303818
reference_title: "The congenital melanocytic nevus: a rare clinical image."
supports: PARTIAL
snippet: 'The congenital melanocytic nevus: a rare clinical image.'
explanation: This case report emphasizes the rarity of congenital melanocytic nevi progressing to melanoma, but no specific prevalence data is provided for the general population.
progression:
- phase: Onset
age_range: Childhood-Adulthood
evidence:
- reference: PMID:28785360
reference_title: "Giant Congenital Melanocytic Nevus (GCMN) - A New Hope for Targeted Therapy?"
supports: SUPPORT
snippet: Although not common, the possible malignant transformation remains one of the most important considerations related to them, as the related lifetime risk of melanoma is 4% to 10%.
explanation: The abstract discusses the risk of melanoma in congenital melanocytic nevi occurring from childhood to adulthood, supporting the statement.
pathophysiology:
- name: Genetic Mutations
description: Post-zygotic mosaic mutations in NRAS (codon 61) and BRAF (V600E) occur during embryogenesis in neural crest-derived melanocyte precursors, driving constitutive MAPK signaling. NRAS mutations are dominant in large/giant CMN (68-94%), while BRAF mutations are less common. Progression to melanoma requires additional alterations including TERT activation, CDKN2A loss, TP53 mutations, and PTEN inactivation.
genes:
- preferred_term: BRAF
term:
id: hgnc:1097
label: BRAF
- preferred_term: NRAS
term:
id: hgnc:7989
label: NRAS
cell_types:
- preferred_term: melanocyte
term:
id: CL:0000148
label: melanocyte
- preferred_term: neural crest cell
term:
id: CL:0011012
label: neural crest cell
biological_processes:
- preferred_term: MAPK cascade
term:
id: GO:0000165
label: MAPK cascade
- preferred_term: cellular senescence
term:
id: GO:0090398
label: cellular senescence
- preferred_term: telomere maintenance
term:
id: GO:0000723
label: telomere maintenance
locations:
- preferred_term: skin
term:
id: UBERON:0002097
label: skin of body
- preferred_term: leptomeninx
term:
id: UBERON:0000391
label: leptomeninx
downstream:
- target: Uncontrolled Cell Growth
- target: Malignant Transformation
description: NRAS mutations drive malignant transformation in congenital melanocytic nevi, with NRAS being the predominant genetic driver in large-giant CMNs.
evidence:
- reference: PMID:24129063
reference_title: "NRAS mutation is the sole recurrent somatic mutation in large congenital melanocytic nevi."
supports: SUPPORT
snippet: Large-giant CMNs displayed NRAS mutations in 94.7% of cases (18/19). ... The results showed that NRAS mutation was the sole recurrent somatic event found in such melanocytic proliferations.
explanation: This study establishes NRAS mutations as the predominant genetic driver in large congenital melanocytic nevi, occurring in nearly 95% of cases, supporting the role of NRAS in the pathogenesis of lesions with malignant potential.
evidence:
- reference: PMID:16750612
reference_title: "Genetic alterations in melanocytic tumors."
supports: SUPPORT
snippet: The most exciting finding is the discovery of oncogenic BRAF mutations in both malignant melanoma and melanocytic nevi. This finding indicates that activation of the mitogen-activated protein kinase pathway may be a critical initiating step of melanocytic neoplasia.
explanation: This study supports the role of BRAF mutations in the pathophysiology of melanoma in melanocytic nevi, including congenital cases.
- reference: PMID:28110826
reference_title: "Congenital Melanocytic Nevus Syndrome: A Case Series."
supports: PARTIAL
snippet: Congenital melanocytic nevus syndrome (CMNS) is the result of an abnormal proliferation of melanocytes in the skin and central nervous system caused by progenitor-cell mutations during embryonic development. Mutations in the NRAS gene have been detected in many of these cells.
explanation: This reference covers NRAS mutations in congenital melanocytic nevus syndrome but does not mention BRAF mutations.
- reference: PMID:32100974
reference_title: "Nevus-associated melanoma: facts and controversies."
supports: SUPPORT
snippet: Melanomas developing on pre-existing congenital or acquired nevi are usually of the superficial spreading subtype and harbor the BRAFV600E mutation.
explanation: This study supports the presence of BRAF mutations in melanomas associated with congenital melanocytic nevi.
- reference: PMID:31111470
reference_title: "Does the gene matter? Genotype-phenotype and genotype-outcome associations in congenital melanocytic naevi."
supports: SUPPORT
snippet: NRAS mosaicism was found in 68%, BRAF in 7% and double wild-type in 25% of cases of CMN. NRAS was the commonest mutation in all sizes of CMN.
explanation: This comprehensive review provides evidence of both NRAS and BRAF mutations in congenital melanocytic nevi, which supports their role in the development of melanoma.
- name: UV Exposure
description: Ultraviolet (UV) radiation can damage the DNA in skin cells, contributing to mutations and the development of melanoma.
notes: Exacerbating Factor
downstream:
- target: DNA Damage
evidence:
- reference: PMID:25268584
reference_title: "The genomic landscape of childhood and adolescent melanoma."
supports: PARTIAL
snippet: the three CNMs contained an activating NRAS Q61 mutation and no TERT-p mutations.
explanation: While the study does not explicitly link UV radiation to melanoma in congenital melanocytic nevus (CNM), it differentiates the mutational spectrum of CNMs from other types of melanoma, suggesting a distinct pathogenesis. Thus, the connection between UV radiation and CNM-related melanoma remains implicit and not clearly defined.
- reference: PMID:33759772
reference_title: "Biology of Melanoma."
supports: NO_EVIDENCE
snippet: validated the role of ultraviolet-induced DNA mutations in melanoma formation
explanation: This reference confirms the role of UV-induced DNA mutations in melanoma formation but does not specifically address melanoma developing from congenital melanocytic nevi.
- name: PI3K-AKT-mTOR Pathway Activation
description: Compensatory activation of the PI3K-AKT-mTOR pathway occurs alongside MAPK signaling, often driven by PTEN loss. This pathway cross-talk promotes cell survival, invasion, and resistance to MEK inhibition. Combined targeting of both MAPK and PI3K pathways represents a rational therapeutic strategy.
genes:
- preferred_term: PTEN
term:
id: hgnc:9588
label: PTEN
biological_processes:
- preferred_term: phosphatidylinositol-mediated signaling
term:
id: GO:0048015
label: phosphatidylinositol-mediated signaling
- preferred_term: TOR signaling
term:
id: GO:0031929
label: TOR signaling
downstream:
- target: Malignant Transformation
- name: DNA Damage
description: Damage to DNA structure from various causes
- name: Uncontrolled Cell Growth
description: Dysregulated cellular proliferation
histopathology:
- name: Melanocytic Neoplasm
finding_term:
preferred_term: Melanocytic Neoplasm
term:
id: NCIT:C7058
label: Melanocytic Neoplasm
frequency: VERY_FREQUENT
description: Malignant melanoma represents a neoplasm stemming from melanocytes.
evidence:
- reference: PMID:27268913
reference_title: "Malignant melanoma: diagnosis, treatment and cancer stem cells."
supports: SUPPORT
snippet: "Malignant melanoma represents a neoplasm stemming from melanocytes"
explanation: Abstract defines melanoma as a neoplasm stemming from melanocytes.
phenotypes:
- category: Dermatologic
name: Pigmented Lesion
frequency: VERY_FREQUENT
diagnostic: true
notes: Changes in size, shape, or color of the nevus
evidence:
- reference: PMID:20888464
reference_title: "Congenital melanocytic nevi."
supports: PARTIAL
snippet: The relative risk for melanoma arising within a congenital nevus is related to the size of the lesion.
explanation: This reference supports the connection between congenital melanocytic nevi and melanoma but does not specify that it is very frequent.
- reference: PMID:34799033
reference_title: "Pigmented Lesions in Children: Update on Clinical, Histopathologic and Ancillary Testing."
supports: PARTIAL
snippet: 'This article provides an update on the clinical, histopathologic, and ancillary testing for 3 categories of particularly challenging pigmented lesions: congenital melanocytic nevi, spitzoid neoplasms, and pediatric melanoma.'
explanation: This reference confirms that melanoma in congenital melanocytic nevi is associated with pigmented lesions and involves clinical, histopathologic evaluation which can count as dermatologic diagnostic, but does not claim it to be very frequent.
- reference: PMID:32392930
reference_title: "[Genetic changes and biological potential of proliferative nodule in congenital pigmented nevus]."
supports: PARTIAL
snippet: Although most of the PN manifest as a benign lesion clinically, it may have certain malignant potential at the genetic level, and warrant long-term monitoring and follow-up.
explanation: This reference suggests that proliferative nodules in congenital melanocytic nevi may have malignant potential, so it acknowledges the risk of melanoma but does not indicate that it is very frequent.
- reference: PMID:34887981
reference_title: "Nevus pigmentosus et pilosus."
supports: PARTIAL
snippet: Giant CMN also known as 'bathing trunk nevus,' 'giant hairy nevus', and 'nevus pigmentosus et pilosus' has highest potential to turn into malignant melanoma.
explanation: The study indicates that giant CMN has a higher potential to develop melanoma, recognizing the risk but not specifying the frequency for all CMNs.
- category: Dermatologic
name: Nodules
frequency: FREQUENT
notes: Raised, firm lesions that can be a sign of melanoma
evidence:
- reference: PMID:27486690
reference_title: "Proliferative Nodules vs Melanoma Arising in Giant Congenital Melanocytic Nevi During Childhood."
supports: PARTIAL
snippet: The differential diagnosis between proliferative nodules (PNs) and melanoma arising in congenital melanocytic nevi (CMN) is crucial, as patients with PNs most often experience no increased risk of melanoma with metastases and death.
explanation: The study discusses the presence of proliferative nodules and melanoma in congenital melanocytic nevi, noting that nodules can be mistaken for melanoma. This partially supports that nodules are a frequent phenotype but doesn't provide a clear frequency or definitively state they are always indicative of melanoma.
- reference: PMID:36122342
reference_title: "A Pigmented Nodule on Congenital Melanocytic Nevus: Challenge."
supports: PARTIAL
snippet: 'A Pigmented Nodule on Congenital Melanocytic Nevus: Challenge.'
explanation: The presence of a pigmented nodule on congenital melanocytic nevi is noted, suggesting it can be a feature but does not elaborate on its frequent occurrence in melanoma specifically.
- reference: PMID:17653760
reference_title: "Melanocytic nevi simulant of melanoma with medicolegal relevance."
supports: PARTIAL
snippet: A group of melanocytic benign nevi are prone to be misdiagnosed as nodular or superficial spreading melanoma. This review illustrates the most frequent forms of these nevi in direct comparison with their malignant morphologic counterparts.
explanation: While it outlines that melanocytic nevi, including nodules, can be misdiagnosed as melanoma, it stops short of stating the frequency with which nodules are a phenotype of melanoma.
- reference: PMID:10591787
reference_title: "[Congenital melanocytic nevi]."
supports: NO_EVIDENCE
snippet: They run an increased life-time risk of transformation into malignant melanoma.
explanation: This reference mentions the risk of congenital melanocytic nevi transforming into melanoma but does not specifically discuss nodules as a frequent phenotype or their dermatologic characteristics.
- category: Systemic
name: Lymphadenopathy
frequency: OCCASIONAL
notes: Swollen lymph nodes may indicate metastasis
evidence:
- reference: PMID:38779794
reference_title: "[Swelling on the neck]."
supports: SUPPORT
snippet: A 30-year-old female patient presented with a swelling of a cervical left lymph node measuring 1x3 cm, which had been presenting for three weeks. Lymph node excision revealed a metastasis of a malignant melanoma.
explanation: The swollen lymph nodes indicating metastasis, with the subject having melanoma, supports the statement of lymphadenopathy as an occasional systemic phenotype of melanoma-in-congenital-melanocytic-nevus.
- reference: PMID:14750241
reference_title: "Nodal melanocytic nevi in sentinel lymph nodes. Correlation with melanoma-associated cutaneous nevi."
supports: PARTIAL
snippet: Melanocytic nevi occurring in lymph nodes create diagnostic difficulty by mimicking metastases. Few studies describe nodal nevi in sentinel lymph nodes (SLNs) excised for melanoma.
explanation: While this source discusses lymph nodes in relation to melanoma, the focus is more on diagnostic difficulty rather than a clear statement of lymphadenopathy as a phenotype.
- reference: PMID:11902552
reference_title: "Lymph-node metastases in patients with melanoma: what is the optimum management?"
supports: SUPPORT
snippet: Lymph-node metastasis is an indicator of poor prognosis for patients with melanoma.
explanation: Lymph-node metastasis being a poor prognosis indicator supports the link between swollen lymph nodes and metastasis in melanoma patients, supporting the statement.
- reference: PMID:18481261
reference_title: "Tumor lymphangiogenesis and melanoma metastasis."
supports: PARTIAL
snippet: Malignant melanomas of the skin primarily metastasize to lymph nodes, and the detection of sentinel lymph node metastases serves as an important prognostic parameter.
explanation: This source confirms the occurrence of lymph node metastasization in melanoma but does not specifically address it in the context of congenital melanocytic nevus.
phenotype_term:
preferred_term: Lymphadenopathy
term:
id: HP:0002716
label: Lymphadenopathy
- category: Dermatologic
frequency: OCCASIONAL
name: Pruritus
notes: Itching of the lesion can sometimes occur
evidence:
- reference: PMID:29971818
reference_title: "Molluscum contagiosum arising in a melanocytic congenital nevus."
supports: PARTIAL
snippet: We report a 6-year-old child with molluscum contagiosum infection arising within an intermediate melanocytic congenital nevus of the thigh, associated with itching and occasional bleeding.
explanation: The literature supports that itching can be associated with a congenital melanocytic nevus, but it does not specifically link this to melanoma. Therefore, the statement is only partially supported.
- reference: PMID:3882344
supports: NO_EVIDENCE
snippet: ''
explanation: This reference discusses melanoma and other melanocytic skin lesions but does not provide evidence about pruritus (itching) in congenital melanocytic nevi.
- reference: PMID:30653639
supports: NO_EVIDENCE
snippet: ''
explanation: This reference discusses congenital melanocytic nevi and other birthmarks but does not mention pruritus (itching) in the context of melanoma in congenital melanocytic nevi.
- reference: PMID:3284306
supports: NO_EVIDENCE
snippet: ''
explanation: This reference focuses on Becker's nevus and does not provide information about pruritus in congenital melanocytic nevi or melanoma.
- reference: PMID:35946357
reference_title: "Clinical history analysis of Japanese melanoma cases and characteristics of melanoma with childhood onset."
supports: NO_EVIDENCE
snippet: ''
explanation: This reference discusses melanoma with childhood onset but does not mention pruritus in the context of congenital melanocytic nevi.
- reference: PMID:8990709
supports: NO_EVIDENCE
snippet: ''
explanation: This reference discusses a congenital atrophic plaque and possible diagnoses including congenital melanocytic nevus but does not mention pruritus.
- reference: PMID:1869648
supports: NO_EVIDENCE
snippet: ''
explanation: This reference discusses neurocutaneous melanosis and congenital melanocytic nevi but does not mention pruritus.
- reference: PMID:15817400
reference_title: "Cutaneous lesions: benign and malignant."
supports: NO_EVIDENCE
snippet: ''
explanation: This reference discusses various cutaneous lesions including congenital melanocytic nevus but does not mention pruritus.
- reference: PMID:28290622
supports: NO_EVIDENCE
snippet: ''
explanation: This reference discusses melanoma and melanocytic nevi in pediatric patients but does not mention pruritus in the context of congenital melanocytic nevi.
- reference: PMID:28954104
supports: NO_EVIDENCE
snippet: ''
explanation: This reference discusses the recurrent nevus phenomenon but does not mention pruritus in the context of congenital melanocytic nevi.
phenotype_term:
preferred_term: Pruritus
term:
id: HP:0000989
label: Pruritus
- category: Dermatologic
frequency: OCCASIONAL
name: Ulceration
notes: Breakdown of skin overlying the melanoma
- category: Dermatologic
frequency: OCCASIONAL
name: Bleeding
notes: Melanoma lesions can sometimes bleed
evidence:
- reference: PMID:29971818
reference_title: "Molluscum contagiosum arising in a melanocytic congenital nevus."
supports: SUPPORT
snippet: We report a 6-year-old child with molluscum contagiosum infection arising within an intermediate melanocytic congenital nevus of the thigh, associated with itching and occasional bleeding.
explanation: The literature mentions bleeding associated with melanocytic congenital nevus, which supports the statement that melanoma lesions in congenital melanocytic nevus can sometimes bleed.
- category: Neurologic
frequency: OCCASIONAL
name: Hydrocephalus
notes: Occurs in symptomatic neurocutaneous melanocytosis with leptomeningeal involvement, indicating CNS spread of melanocytic proliferation
phenotype_term:
preferred_term: Hydrocephalus
term:
id: HP:0000238
label: Hydrocephalus
- category: Neurologic
frequency: OCCASIONAL
name: Seizures
notes: Associated with CNS involvement in neurocutaneous melanocytosis
phenotype_term:
preferred_term: Seizure
term:
id: HP:0001250
label: Seizure
diagnosis:
- name: Dermatoscopic Examination
notes: Detailed visual examination of skin lesions
evidence:
- reference: PMID:22481578
reference_title: "Dermoscopic criteria and melanocytic lesions."
supports: SUPPORT
snippet: Dermoscopy is a noninvasive, in vivo method for the early diagnosis of malignant melanoma and the differential diagnosis of pigmented lesions of the skin.
explanation: The dermoscopic examination is highlighted as a crucial tool in diagnosing malignant melanoma, supporting the statement that melanoma in congenital melanocytic nevus can be diagnosed through dermatoscopic examination.
- name: Skin Biopsy
notes: Histopathological examination to confirm melanoma
evidence:
- reference: PMID:9357498
reference_title: "Superficial congenital compound melanocytic nevus. Another pitfall in the diagnosis of malignant melanoma."
supports: SUPPORT
snippet: Awareness of these simulants may prevent misinterpretation of a benign superficial congenital compound melanocytic nevus as a malignant melanoma.
explanation: This indicates that histopathological examination, which includes skin biopsy, is indeed a method used to diagnose melanoma in congenital melanocytic nevus (CMN), supporting the use of skin biopsy for confirming melanoma.
- reference: PMID:27096540
reference_title: "Intralesional (incision) biopsy for melanoma diagnosis: the rules and the exception."
supports: SUPPORT
snippet: Intralesional (incision) biopsy for melanoma diagnosis can be warranted for large lesions or for those lesions whose in-toto excision leads to cosmetic and/or functional impairment.
explanation: This supports the statement as it mentions that biopsies, a form of histopathological examination, are used for diagnosing melanoma in specific cases related to CMNs.
- reference: PMID:24786371
reference_title: "Childhood melanoma: an increasingly important health problem in the USA."
supports: PARTIAL
snippet: Childhood melanoma is often amelanotic and may also appear as raised or ulcerated lesions commonly mistaken for warts or other benign skin conditions. Excision and full-thickness punch biopsies are indicated for suspicious lesions.
explanation: This partially supports the statement by indicating the use of full-thickness punch biopsies for suspicious lesions in a pediatric context, but it does not specifically mention congenital melanocytic nevus.
- name: Sentinel Lymph Node Biopsy
notes: Determines spread to lymph nodes
evidence:
- reference: PMID:9283554
reference_title: "Sentinel lymph node biopsy in melanoma of the head and neck."
supports: PARTIAL
snippet: The sentinel node was successfully identified in 55 patients (95 percent)... By combining the two mapping techniques in patients with melanoma of the head and neck, the sentinel node(s) can be mapped and identified individually, similar to melanoma in other locations.
explanation: This study demonstrates the use of sentinel lymph node biopsy for melanoma, confirming its role in determining the spread to lymph nodes. However, it does not specifically address melanoma within congenital melanocytic nevus.
- reference: PMID:32729623
reference_title: "Genetic investigation of nodal melanocytic nevi in cases of giant congenital melanocytic nevus."
supports: PARTIAL
snippet: Nodal melanocytic nevi are common incidental findings in lymph nodes that have been removed during sentinel lymph node biopsy for melanoma.
explanation: This study acknowledges the use of sentinel lymph node biopsy in melanomas, and also mentions nodal melanocytic nevi as incidental findings. However, it does not directly confirm the diagnosis of melanoma within congenital melanocytic nevi using this technique.
- reference: PMID:22864798
reference_title: "The unique clinical characteristics of melanoma diagnosed in children."
supports: NO_EVIDENCE
snippet: Children with melanoma have higher rates of SLN metastases (29%) than adults with comparable melanomas. Despite the higher incidence of nodal metastases, survival is equal to or better than what is reported for adults.
explanation: This study discusses the rates of sentinel lymph node metastases in pediatric melanoma but does not specifically address the congenital melanocytic nevus as the primary condition.
genetic:
- name: BRAF
association: Mutations
evidence:
- reference: PMID:16750612
reference_title: "Genetic alterations in melanocytic tumors."
supports: SUPPORT
snippet: The most exciting finding is the discovery of oncogenic BRAF mutations in both malignant melanoma and melanocytic nevi.
explanation: The excerpt indicates that BRAF mutations are found in both malignant melanoma and melanocytic nevi, supporting the statement.
- reference: PMID:37156689
reference_title: "The association of BRAF V600E gene mutation with proliferative activity and histopathological characteristics of congenital melanocytic nevi in children."
supports: SUPPORT
snippet: A lot of congenital melanocytic nevi (CMN) carry the somatic mutation in the oncogene BRAF V600E.
explanation: The excerpt clearly states the presence of BRAF mutations in congenital melanocytic nevi.
- reference: PMID:31111470
reference_title: "Does the gene matter? Genotype-phenotype and genotype-outcome associations in congenital melanocytic naevi."
supports: SUPPORT
snippet: BRAF is confirmed as a much rarer cause of multiple CMN.
explanation: Although BRAF is a less common mutation in CMN, its presence still supports the statement.
- reference: PMID:36085074
reference_title: "Association of novel MUC16, MAP3K15 and ABCA1 mutation with giant congenital melanocytic nevus."
supports: SUPPORT
snippet: Mutations in NRAS have been previously detected in GCMN, but mutations in BRAF are generally lacking in the Chinese population.
explanation: The excerpt suggests the presence of BRAF mutations in GCMN, though less frequent in the Chinese population.
- name: NRAS
association: Mutations
notes: Post-zygotic mosaic mutations at codon 61 (Q61K/R) are the dominant driver in 68-94% of large/giant CMN and associated melanomas
evidence:
- reference: PMID:33851646
reference_title: "NRAS mutant melanoma arising in a giant congenital melanocytic nevus in an infant."
supports: SUPPORT
snippet: NRAS mutant melanoma arising in a giant congenital melanocytic nevus in an infant.
explanation: This reference directly describes a case of NRAS mutant melanoma arising in the context of giant congenital melanocytic nevus.
- reference: PMID:31111470
reference_title: "Does the gene matter? Genotype-phenotype and genotype-outcome associations in congenital melanocytic naevi."
supports: SUPPORT
snippet: Multiple congenital melanocytic naevi (CMN) have been shown to be caused by NRAS mosaic mutations in 70-80% of cases.
explanation: This reference provides statistical data supporting the association between NRAS mutations and congenital melanocytic nevi.
- name: TERT
association: Promoter mutations
notes: TERT promoter activation or amplification associated with malignant transformation, enabling telomere maintenance and replicative immortality
- name: CDKN2A
association: Loss of function
notes: Deletion or loss enables escape from oncogene-induced senescence and promotes progression to invasive melanoma
- name: TP53
association: Mutations
notes: Somatic mutations in progressed lesions contribute to genomic instability and malignant transformation
- name: PTEN
association: Loss of function
notes: Loss or inactivation leads to PI3K-AKT-mTOR pathway activation, cooperating with MAPK signaling to promote survival and invasion
- name: MET
association: Pathway activation
notes: HGF/MET signaling enhances RAS-MAPK and PI3K-AKT pathways, implicated in both cutaneous and leptomeningeal melanocytic proliferation
- name: RAF1
association: Gene fusions
notes: Rare mosaic RAF1 fusions reported as oncogenic drivers in atypical CMN cases
environmental:
- name: UV Radiation
description: Sunlight and tanning beds
effect: DNA Damage
exposure_term:
preferred_term: Ultraviolet radiation exposure
term:
id: ECTO:0000006
label: exposure to ultraviolet radiation
evidence:
- reference: PMID:32281145
reference_title: "Solar ultraviolet-induced DNA damage response: Melanocytes story in transformation to environmental melanomagenesis."
supports: SUPPORT
snippet: Both UVB and UVA are physiologically responsible for a plethora of skin ailments, including skin cancers. The UVR is readily absorbed by the genomic DNA of skin cells, causing DNA bond distortion and UV-induced DNA damage.
explanation: This excerpt supports the statement that UV radiation from sunlight causes DNA damage, which is relevant to Melanoma_in_Congenital_Melanocytic_Nevus.
- reference: PMID:35298329
reference_title: "Artificial tanning devices (Sunbeds): where do we stand?"
supports: SUPPORT
snippet: Sunbed use is responsible for a significant proportion of both melanoma and non-melanoma skin cancers, especially in patients exposed to this practice in early life, premature skin ageing, immunosuppression, skin burns, and eye damage.
explanation: This supports the statement by indicating that artificial tanning devices, such as tanning beds, contribute to the development of skin cancers, including melanoma, through exposure to UV radiation.
- reference: PMID:30113042
reference_title: "Melanoma - role of the environment and genetics."
supports: SUPPORT
snippet: The main etiologic factor is ultraviolet radiation, from the sun as well as artificial tanning devices.
explanation: This explains that UV radiation from both natural sunlight and artificial tanning devices is a major factor in melanoma development.
- reference: PMID:25252745
reference_title: "Skin cancer: role of ultraviolet radiation in carcinogenesis."
supports: SUPPORT
snippet: UV radiation is a carcinogen known to play a role in the development of non-melanoma and melanoma skin cancers. Acute and chronic exposure to UV radiation causes clinical and biological effects that promote the unregulated proliferation of skin cells.
explanation: This information supports the statement by highlighting the role of UV radiation in the development of melanoma, through DNA damage.
treatments:
- name: Surgical Excision
description: Removal of the melanoma and surrounding tissue
evidence:
- reference: PMID:33010324
reference_title: "Segmental excision of congenital melanocytic nevus by multiple incisions."
supports: NO_EVIDENCE
snippet: Segmental excision of congenital melanocytic nevus by multiple incisions.
- reference: PMID:11079795
reference_title: "Management of malignant melanoma."
supports: SUPPORT
snippet: An excisional biopsy is the appropriate diagnostic procedure for a skin lesion suspected of being a melanoma.
explanation: Excision is recommended for diagnosing and treating melanoma.
- reference: PMID:14379056
reference_title: "The surgical treatment of melanoma."
supports: SUPPORT
snippet: The tenet of excision and dissection in continuity where feasible of the primary melanoma and the regional lymph nodes is reemphasized.
explanation: This reference supports the surgical excision of melanoma, including melanoma arising in congenital melanocytic nevus.
- reference: PMID:22980259
reference_title: "Congenital melanocytic nevi: where are we now? Part II. Treatment options and approach to treatment."
supports: PARTIAL
snippet: 'Treatment of congenital melanocytic nevi (CMN) is generally undertaken for 2 reasons: (1) to reduce the chances of cutaneous malignant melanoma and (2) for cosmetic reasons.'
explanation: Excision is one of several treatments considered but the exact treatment for melanoma is not specified.
- reference: PMID:1615092
reference_title: "Congenital malignant melanoma."
supports: SUPPORT
snippet: The child underwent a complete surgical excision of this lesion with immediate coverage by partial-thickness skin grafts.
explanation: The reference describes a case where melanoma in a congenital melanocytic nevus was treated by surgical excision.
- reference: PMID:15817400
reference_title: "Cutaneous lesions: benign and malignant."
supports: SUPPORT
snippet: Surgical excision may be considered for cosmetic purposes and to reduce the small risk for the development of malignancy within each lesion.
explanation: Surgical excision is recommended for congenital melanocytic nevus to mitigate cancer risk.
treatment_term:
preferred_term: surgical procedure
term:
id: MAXO:0000004
label: surgical procedure
- name: Immunotherapy
description: Use of drugs to stimulate the immune system to target melanoma cells
evidence:
- reference: PMID:27453302
reference_title: "(Neo)adjuvant systemic therapy for melanoma."
supports: SUPPORT
snippet: In recent years systemic targeted- and immunotherapy have proven to be beneficial in advanced melanoma and could be a promising strategy for (neo)adjuvant treatment of patients with resectable high risk melanomas as well.
explanation: This indicates that immunotherapy, which stimulates the immune system to target melanoma cells, could be beneficial for melanoma in high-risk patients, supporting the statement.
- reference: PMID:16762733
reference_title: "Immunotherapy of melanoma."
supports: SUPPORT
snippet: Melanoma has been widely studied as a target for immunotherapy because it has been considered more susceptible to immune attack than other tumors... This article reviews the recent clinical results of trials exploring different immunotherapy strategies against melanoma.
explanation: The literature supports that immunotherapy is used to target melanoma cells, supporting the statement.
- reference: PMID:36435868
reference_title: "Targeted Therapy for Melanomas Without BRAF V600 Mutation."
supports: PARTIAL
snippet: Immune checkpoint inhibitors (ICIs) have revolutionized the treatment paradigm for patients with metastatic melanoma; however, there remains an unmet clinical need for alternative treatment options for those patients who are either intolerant or refractory to immunotherapy.
explanation: This suggests that while immunotherapy is used, it is not universally effective for all patients, therefore partially supporting the statement.
treatment_term:
preferred_term: immunotherapy
term:
id: NCIT:C15262
label: Immunotherapy
- name: Targeted Therapy
description: Drugs that target specific genetic mutations in melanoma cells, such as BRAF inhibitors
evidence:
- reference: PMID:24880943
reference_title: "Targeted therapies for cutaneous melanoma."
supports: SUPPORT
snippet: In cutaneous melanomas with BRAF V600 mutations the selective RAF inhibitors, vemurafenib and dabrafenib, and the MEK inhibitor, trametinib, have demonstrated survival benefits.
explanation: This reference indicates that targeted therapies, such as BRAF inhibitors, are effective in treating melanomas with specific genetic mutations.
- reference: PMID:30792255
reference_title: "Giant Congenital Melanocytic Nevus Treated With Trametinib."
supports: PARTIAL
snippet: We present the case of a 7-year-old girl with a giant congenital melanocytic nevus that had an AKAP9-BRAF fusion and was treated with trametinib, which resulted in rapid resolution of the patient's lifelong, intractable pain and pruritus as well as dramatic improvement in the extent of her nevus.
explanation: This reference supports the use of trametinib, a targeted therapy, in treating a congenital melanocytic nevus with a specific genetic mutation, though the primary outcome discussed is symptom relief rather than melanoma treatment.
treatment_term:
preferred_term: targeted therapy
term:
id: NCIT:C93352
label: Targeted Therapy
- name: Radiation Therapy
description: Use of high-energy radiation to kill cancer cells or shrink tumors
evidence:
- reference: PMID:8977557
reference_title: "Radiation therapy for malignant melanoma."
supports: PARTIAL
snippet: Although surgery remains the treatment of choice for the vast majority of localized melanomas, available data indicate that radiation therapy is a viable alternative for a few subsets of patients in whom surgery would result in cosmetic or functional deformity.
explanation: Radiation therapy is recommended in certain circumstances, but is not the primary treatment method for localized melanomas which include melanomas arising from congenital melanocytic nevi.
- reference: PMID:12609784
reference_title: "Laser therapy of giant congenital melanocytic nevi."
supports: NO_EVIDENCE
snippet: Lasers should only be regarded as a treatment option for GCMN that cannot be surgically excised.
explanation: The provided abstract discusses laser therapy as an alternative to surgery for GCMN but does not mention radiation therapy.
- reference: PMID:28092363
reference_title: "Mouse models of UV-induced melanoma: genetics, pathology, and clinical relevance."
supports: NO_EVIDENCE
snippet: This review will focus exclusively on genetically engineered mouse models of UVR-induced melanoma.
explanation: The provided abstract is about mouse models for UV-induced melanoma and does not discuss the treatment of melanomas arising from congenital melanocytic nevi with radiation therapy.
- reference: PMID:19880040
reference_title: "Childhood melanoma."
supports: PARTIAL
snippet: Adjuvant therapies such as chemotherapy, immunotherapy, and radiation therapy can be used in advanced cases.
explanation: Radiation therapy is listed as an adjuvant treatment in advanced pediatric melanoma cases, which can include those arising from conditions like congenital melanocytic nevi.
- reference: PMID:29958291
reference_title: "Enhancing radiosensitivity of melanoma cells through very high dose rate pulses released by a plasma focus device."
supports: PARTIAL
snippet: Radiation therapy is a useful and standard tumor treatment strategy... Some strategies are focused on enhancement of accuracy in ionizing radiation delivery and on the generation of greater radiation beams...
explanation: The abstract discusses radiation therapy and its enhancement but does not specifically address radiation therapy for melanomas originating from congenital melanocytic nevi.
treatment_term:
preferred_term: radiation therapy
term:
id: MAXO:0000014
label: radiation therapy
- name: Chemotherapy
description: Use of drugs to kill rapidly dividing cells, including cancer cells
evidence:
- reference: PMID:22980259
reference_title: "Congenital melanocytic nevi: where are we now? Part II. Treatment options and approach to treatment."
supports: PARTIAL
snippet: 'Treatment of congenital melanocytic nevi (CMN) is generally undertaken for 2 reasons: (1) to reduce the chances of cutaneous malignant melanoma and (2) for cosmetic reasons. Over the past century, a large number of treatments for CMN have been described in the literature. These include excision, dermabrasion, curettage, chemical peels, radiation therapy, cryotherapy, electrosurgery, and lasers. Only low-level evidence supporting these approaches is available, and large randomized controlled trials have not been published.'
explanation: Although chemotherapy is not explicitly mentioned, the focus on various treatments for melanoma suggests that a range of therapeutic approaches exists.
- reference: PMID:27268913
reference_title: "Malignant melanoma: diagnosis, treatment and cancer stem cells."
supports: PARTIAL
snippet: Malignant melanoma represents a neoplasm stemming from melanocytes or the cells that develop from melanocytes. Melanocytes, pigment-producing cells, arise from the neural crest and migrate to their final destinations in the skin, uveal tract, meninges, and mucosa. Most melanocytes are found at the epidermal-dermal junction of the skin, and the vast majority of melanocytes arise from cutaneous sites. Cancerous growths develop when unrepaired DNA damage to skin cells (most often caused by ultraviolet radiation from sunshine or tanning beds) triggers mutations (genetic defects) that lead the skin cells to multiply rapidly and form malignant tumours.
explanation: While chemotherapy is an established approach for treating malignant melanoma, this reference does not provide explicit information about its use specifically in congenital melanocytic nevus-related melanoma.
treatment_term:
preferred_term: chemotherapy
term:
id: MAXO:0000647
label: chemotherapy
notes: Early detection and treatment are critical for improving outcomes in melanoma arising in congenital melanocytic nevi.
disease_term:
preferred_term: melanoma in congenital melanocytic nevus
term:
id: MONDO:0850110
label: melanoma in congenital melanocytic nevus
classifications:
icdo_morphology:
classification_value: Melanoma
harrisons_chapter:
- classification_value: cancer
- classification_value: solid tumor
references:
- reference: DOI:10.1007/s00428-024-04011-3
title: 'Congenital melanocytic neoplasms: clinical, histopathological and recent molecular developments'
findings: []
- reference: DOI:10.21873/anticanres.17341
title: Therapeutic Strategies in Neurocutaneous Melanocytosis
findings: []
- reference: DOI:10.3390/cancers16142508
title: 'Primary Meningeal Melanocytic Tumors of the Central Nervous System: A Review from the Ultra-Rare Brain Tumors Task Force of the European Network for Rare Cancers (EURACAN)'
findings: []
- reference: DOI:10.46439/cancerbiology.6.075
title: Oncogenic specificity in nevus and melanoma formation
findings: []
Disease Pathophysiology Research Report
Target Disease - Disease Name: Melanoma arising in Congenital Melanocytic Nevus (CMN), including CNS involvement (neurocutaneous melanocytosis, NCM) - MONDO ID: Not definitively assigned for the combined entity in retrieved sources (entity spans congenital melanocytic nevus and melanoma; leave blank pending curation) - Category: Skin Cancer
1) Core Pathophysiology: Current Understanding Melanoma arising within CMN is a developmental-oncologic process initiated by post-zygotic mosaic mutations in melanocytic lineage, most commonly NRAS codon 61 substitutions, with less frequent BRAF V600E and mosaic BRAF/RAF1 fusions. These events occur during embryogenesis in neural crest-derived melanocyte precursors or Schwann cell precursors, leading to clonal nevomelanocyte expansion in skin and, in some patients, parallel seeding of leptomeninges (NCM). Constitutive MAPK/ERK signaling is the central dysregulated pathway, with adaptive/compensatory activation of PI3K–AKT–mTOR contributing to survival and progression. Progression from nevus to melanoma typically requires additional alterations enabling telomere maintenance (TERT promoter activation), escape from oncogene-induced senescence (loss of CDKN2A/p16; TP53 pathway changes), and growth/invasion advantages (e.g., PTEN loss; copy-number gains such as NRAS amplification in select cases). Epigenomic reprogramming and distinct methylation profiles have been reported in pediatric malignant neurocutaneous melanocytic neoplasms, supporting a role for chromatin state in classification and possibly pathogenesis. Clinically, early CNS MRI abnormalities in infants with large/giant CMN correlate with higher risk of childhood melanoma and poor NCM outcomes. (Basu 2024, AntiCancer Research, Dec 2024, https://doi.org/10.21873/anticanres.17341; Salgado et al. 2025, Virchows Archiv, Jan 2025, https://doi.org/10.1007/s00428-024-04011-3; Kaminiow et al. 2025, Journal of Cancer Biology, Aug 2025, https://doi.org/10.46439/cancerbiology.6.075) (basu2024therapeuticstrategiesin pages 2-3, salgado2025congenitalmelanocyticneoplasms pages 3-4, salgado2025congenitalmelanocyticneoplasms pages 10-11, kaminiow2025oncogenicspecificityin pages 2-3, kaminiow2025oncogenicspecificityin pages 3-4)
Key dysregulated pathways and cellular processes include: - MAPK/ERK signaling: constitutive activation via NRAS Q61, BRAFV600E, and RAF fusions; downstream MEK/ERK drives proliferation and survival. (salgado2025congenitalmelanocyticneoplasms pages 3-4, basu2024therapeuticstrategiesin pages 2-3) - PI3K–AKT–mTOR signaling: cross-talk and compensatory activation, especially upon MEK inhibition; contributes to survival, invasion, and resistance. (salgado2025congenitalmelanocyticneoplasms pages 3-4, basu2024therapeuticstrategiesin pages 2-3) - Telomere maintenance: TERT promoter activation or amplification implicated in malignant transformation. (salgado2025congenitalmelanocyticneoplasms pages 3-4) - Senescence and cell cycle: nevi often undergo oncogene-induced senescence; progression entails CDKN2A/p16 loss and TP53 pathway disruption, enabling continued cycling. (basu2024therapeuticstrategiesin pages 2-3, kaminiow2025oncogenicspecificityin pages 2-3, hamed2025oncogenicdriversand pages 40-44) - Copy-number variation: includes NRAS amplification in some NCM-associated melanomas; broader CNA and LOH patterns associated with progression. (salgado2025congenitalmelanocyticneoplasms pages 10-11, kaminiow2025oncogenicspecificityin pages 2-3) - Epigenomic change: disease-specific methylation profiles reported in pediatric malignant neurocutaneous melanocytic neoplasms; supports diagnostic classification. (salgado2025congenitalmelanocyticneoplasms pages 10-11) - Microenvironment/growth factors: HGF/MET signaling enhances RAS→MAPK and PI3K–AKT pathways; increased mast cells reported in large/giant CMN. (basu2024therapeuticstrategiesin pages 2-3, salgado2025congenitalmelanocyticneoplasms pages 10-11) - Neurotropism/leptomeningeal spread: early mosaic mutation in neural crest/SCP lineages with seeding of leptomeninges explains NCM; diffuse meningeal melanomatosis often NRAS-driven, whereas circumscribed meningeal melanocytic tumors carry GNAQ/GNA11/SF3B1/EIF1AX/BAP1—useful for differential diagnosis. (Pellerino et al. 2024, Cancers, Jul 2024, https://doi.org/10.3390/cancers16142508) (basu2024therapeuticstrategiesin pages 2-3, salgado2025congenitalmelanocyticneoplasms pages 3-4, salgado2025congenitalmelanocyticneoplasms pages 10-11)
2) Key Molecular Players - Drivers and effectors (HGNC): NRAS (HGNC:7989), BRAF (HGNC:1097), RAF1 (HGNC:9829), MAP2K1/MEK1 (HGNC:6840), MAP2K2/MEK2 (HGNC:6842), TERT (HGNC:11730), CDKN2A/p16 (HGNC:1787), TP53 (HGNC:11998), PTEN (HGNC:9588), MET (HGNC:7029), HGF (HGNC:4886), MC1R (HGNC:6935), GNAQ (HGNC:4399), GNA11 (HGNC:4380), S1PR3 (HGNC:3169). (salgado2025congenitalmelanocyticneoplasms pages 3-4, basu2024therapeuticstrategiesin pages 2-3, salgado2025congenitalmelanocyticneoplasms pages 10-11) - Alterations: post-zygotic NRAS Q61K/R mosaic mutations (dominant in large/giant CMN/NCM), BRAFV600E in a subset, mosaic BRAF and RAF1 fusions (rare), MEK mutations in progressed disease, TERT promoter activation, CDKN2A loss, TP53 alterations, PTEN loss, occasional NRAS amplification in NCM-associated melanoma; rare S1PR3 variant in an NCM case. (salgado2025congenitalmelanocyticneoplasms pages 3-4, salgado2025congenitalmelanocyticneoplasms pages 10-11, basu2024therapeuticstrategiesin pages 2-3) - Cell types (CL): melanocytes (CL:0000148), neural crest cells (CL:0000133), Schwann cell precursors/Schwann cells (CL:0002573), mast cells (CL:0000097), tumor-associated macrophages (CL:0000235). (salgado2025congenitalmelanocyticneoplasms pages 10-11) - Anatomical locations (UBERON): skin (UBERON:0002097), epidermis (UBERON:0001003), dermis (UBERON:0002067), leptomeninx (UBERON:0002416), brain (UBERON:0000955). (basu2024therapeuticstrategiesin pages 2-3, salgado2025congenitalmelanocyticneoplasms pages 3-4) - Chemical entities (CHEBI) relevant to mechanism/therapy: trametinib (MEK inhibitor; CHEBI:75962), azacitidine (DNA methyltransferase inhibitor; CHEBI:47616), PI3K pathway inhibitors (e.g., alpelisib, CHEBI:90684; conceptually referenced as a class in reviews). Case reports and reviews describe MAPK inhibition benefit and emerging combined MAPK–PI3K strategies in NRAS-driven disease. (hamed2025oncogenicdriversand pages 40-44, salgado2025congenitalmelanocyticneoplasms pages 3-4)
Key molecular players artifact | Gene/Protein (HGNC) | Alteration / Mechanism | Pathway(s) | Role in CMN / Melanoma | Evidence (year, URL) | |---|---|---|---|---| | NRAS (NRAS) | Post‑zygotic activating codon‑61 mutations (Q61K/R) — mosaic in embryogenesis | MAPK/ERK; cross‑talk with PI3K‑AKT/mTOR | Dominant initiating driver in large/giant CMN and neurocutaneous melanocytosis (NCM); present in affected skin and CNS; predisposes to malignant progression when additional hits accumulate | 2025, https://doi.org/10.1007/s00428-024-04011-3 (salgado2025congenitalmelanocyticneoplasms pages 3-4), 2024, https://doi.org/10.21873/anticanres.17341 (basu2024therapeuticstrategiesin pages 2-3) | | BRAF (BRAF) | Somatic V600E in a subset of CMN; less commonly mosaic BRAF fusions | MAPK/ERK | Alternative initiator in some CMN with distinct histology and hyperproliferative phenotype; BRAF fusions act as mosaic drivers in select cases | 2025, https://doi.org/10.1007/s00428-024-04011-3 (salgado2025congenitalmelanocyticneoplasms pages 3-4), 2025 review (kaminiow2025oncogenicspecificityin pages 2-3) | | BRAF fusions (BRAF) | Mosaic gene fusions creating constitutively active BRAF fusion proteins | MAPK/ERK | Recurrent mosaic drivers in some CMN cases; potentially targetable by MAPK pathway inhibition | 2025, https://doi.org/10.1007/s00428-024-04011-3 (salgado2025congenitalmelanocyticneoplasms pages 3-4) | | RAF1 fusions (RAF1) | Oncogenic gene fusions activating RAF1 reported in rare CMN cases | MAPK/ERK | Rare alternative oncogenic event contributing to nevogenesis or atypical phenotypes | 2025, https://doi.org/10.1007/s00428-024-04011-3 (salgado2025congenitalmelanocyticneoplasms pages 3-4) | | MAP2K1 / MAP2K2 (MEK1/2) | Activating mutations or secondary pathway activation downstream of RAS/RAF | MAPK cascade (MEK→ERK) | Observed in progression/advanced lesions; contribute to constitutive MAPK signalling and are therapeutic targets (MEK inhibitors) | 2025 review (kaminiow2025oncogenicspecificityin pages 2-3) | | TERT promoter (TERT) | Promoter mutations or activation/amplification increasing telomerase expression | Telomere maintenance; replicative immortality | Associated with malignant transformation in melanocytic lesions, conferring proliferative advantage during progression from CMN to melanoma | 2025 review, https://doi.org/10.1007/s00428-024-04011-3 (salgado2025congenitalmelanocyticneoplasms pages 3-4) | | CDKN2A (CDKN2A / p16) | Deletion or loss of function leading to cell‑cycle checkpoint abrogation | Cell‑cycle regulation (G1/S) | Loss enables escape from oncogene‑induced senescence (OIS) and promotes malignant progression from CMN to invasive melanoma | 2025 review (kaminiow2025oncogenicspecificityin pages 2-3), clinical reports (hamed2025oncogenicdriversand pages 40-44) | | TP53 (TP53) | Somatic mutation/inactivation in progressed lesions | Cell cycle control, apoptosis, genome stability | Enriched in invasive/malignant CMN‑associated melanomas; contributes to genomic instability and progression | 2025 case/review (hamed2025oncogenicdriversand pages 40-44), 2025 review (salgado2025congenitalmelanocyticneoplasms pages 3-4) | | PTEN (PTEN) | Loss or inactivation leading to PI3K pathway activation | PI3K‑AKT‑mTOR | Cooperates with MAPK activation to promote survival, invasion, and therapy resistance in progressing CMN/melanoma | 2025, https://doi.org/10.1007/s00428-024-04011-3 (salgado2025congenitalmelanocyticneoplasms pages 3-4) | | MC1R (MC1R) | Germline variants acting as modifying risk alleles | Pigmentation and DNA‑damage response pathways | Germline modifier of melanoma susceptibility in patients with CMN; may influence phenotypic risk | 2025 clinical commentary (hamed2025oncogenicdriversand pages 40-44) | | HGF / MET (HGF, MET) | Paracrine/autocrine growth‑factor signalling amplifying RAS→MAPK and PI3K pathways | MAPK, PI3K‑AKT, PAK/STAT3 | Implicated experimentally in facilitating both skin and leptomeningeal melanocytic lesions and may enhance proliferation/motility (model of neurotropism) | 2024, https://doi.org/10.21873/anticanres.17341 (basu2024therapeuticstrategiesin pages 2-3) | | GNAQ / GNA11 (GNAQ, GNA11) | Activating Gq‑pathway mutations typical of uveal/meningeal melanocytic tumors | Gq → PKC / MAPK | Characteristic of circumscribed primary meningeal melanocytic tumors and distinct from NRAS‑driven diffuse NCM; useful for CNS differential diagnosis | 2025, https://doi.org/10.1007/s00428-024-04011-3 (salgado2025congenitalmelanocyticneoplasms pages 3-4) | | S1PR3 (S1PR3) | Rare somatic missense variant reported in an NCM case (candidate rare driver) | GPCR signalling with potential effects on migration/survival | Single‑case evidence implicates S1PR3 alteration in malignant progression within NCM; requires validation in larger series | 2024 case report (salgado2025congenitalmelanocyticneoplasms pages 10-11) |
Table: A compact, evidence‑linked markdown table listing major genes, mechanisms, pathways and their roles in CMN‑associated melanoma, with literature context IDs and URLs for source tracing.
3) Biological Processes (candidate GO terms) - MAPK cascade; positive regulation of ERK1/2 cascade; RAS protein signal transduction; regulation of cell cycle G1/S transition; negative regulation of cell cycle arrest; telomere maintenance via telomerase; cellular senescence; apoptotic process; melanocyte differentiation; neural crest cell migration; regulation of cell migration; response to UV; regulation of immune response. These processes map to the mechanistic axes described above (MAPK/PI3K, telomere/senescence, developmental migration, and immune context). (basu2024therapeuticstrategiesin pages 2-3, salgado2025congenitalmelanocyticneoplasms pages 3-4, salgado2025congenitalmelanocyticneoplasms pages 10-11)
4) Cellular Components (candidate GO terms) - Plasma membrane and lipid raft (RAS/RTK/GPCR initiation), cytosol (RAF–MEK–ERK), nucleus (ERK-regulated transcription, TP53, CDKN2A/p16), chromatin (epigenomic states), nucleoplasm/telomere (TERT-mediated maintenance), extracellular space (HGF, cytokines). (basu2024therapeuticstrategiesin pages 2-3, salgado2025congenitalmelanocyticneoplasms pages 3-4)
5) Disease Progression: Sequence of Events - Initiation (embryogenesis): post-zygotic mosaic mutation in NRAS Q61 (dominant) or less commonly BRAF V600 or BRAF/RAF1 fusion in neural crest–derived melanocytic lineage leading to clonal nevomelanocyte expansion in skin; parallel dissemination to leptomeninges yields asymptomatic melanocytosis in some infants. (salgado2025congenitalmelanocyticneoplasms pages 3-4, salgado2025congenitalmelanocyticneoplasms pages 10-11) - Nevus formation and growth arrest: constitutive MAPK signaling induces proliferation but often triggers oncogene-induced senescence (OIS), with p16 upregulation limiting growth. Lesion size/number reflect timing and cell-of-origin (earlier events → larger/multiple CMN and higher NCM risk). (basu2024therapeuticstrategiesin pages 2-3, kaminiow2025oncogenicspecificityin pages 3-4) - Progression to melanoma: acquisition of additional hits—TERT promoter activation, CDKN2A loss, TP53/PI3K–AKT–mTOR pathway changes (including PTEN loss), copy-number alterations (e.g., NRAS amplification)—enables senescence bypass, replicative immortality, invasion, and metastasis. Pediatric CNS-predominant disease (NCM) can progress to diffuse leptomeningeal melanomatosis with aggressive clinical behavior. (salgado2025congenitalmelanocyticneoplasms pages 10-11, kaminiow2025oncogenicspecificityin pages 2-3, basu2024therapeuticstrategiesin pages 2-3) - Clinical manifestations: rapid growth or new nodules within CMN, ulceration, and symptoms of CNS involvement (hydrocephalus, seizures) herald malignant transformation in a minority; early MRI abnormalities correlate with worse outcomes in NCM. (basu2024therapeuticstrategiesin pages 2-3, salgado2025congenitalmelanocyticneoplasms pages 3-4)
6) Phenotypic Manifestations (HP terms) - Multiple/large/giant congenital melanocytic nevi (HP:0001045, HP:0001050), hypertrichosis over nevi (HP:0002231), pigmentary mosaicism patterns (HP:0007518), neurocutaneous melanosis with leptomeningeal melanocytosis (HP:0006886), hydrocephalus (HP:0000238), seizures (HP:0001250), developmental delay (HP:0001263) in symptomatic NCM; malignant melanoma within CMN (HP:0009725). Clinical risk increases with giant lesions and early CNS abnormalities. (basu2024therapeuticstrategiesin pages 2-3, salgado2025congenitalmelanocyticneoplasms pages 3-4)
Recent Developments and Latest Research (2023–2024 priority) - Therapeutic insights in NCM: 2024 review synthesizes lack of standard therapies, highlights mosaic NRAS/BRAF biology, and preclinical rationale for targeting MAPK and PI3K–AKT–mTOR; documents poor outcomes in symptomatic NCM and risks associated with CSF shunting (including peritoneal seeding). (Basu 2024, AntiCancer Research, Dec 2024, https://doi.org/10.21873/anticanres.17341) (basu2024therapeuticstrategiesin pages 2-3) - Differential CNS melanocytic tumor genetics: 2024 EURACAN review delineates NRAS/BRAF in diffuse leptomeningeal disease versus GNAQ/GNA11/SF3B1/EIF1AX/BAP1 in circumscribed primary meningeal melanocytic tumors—important for diagnosis and management. (Pellerino et al. 2024, Cancers, Jul 2024, https://doi.org/10.3390/cancers16142508) (basu2024therapeuticstrategiesin pages 2-3) - 2025 updates (relevant to 2023–2024 themes): comprehensive review of congenital melanocytic neoplasms consolidates evidence for NRAS Q61 mosaicism, the emergence of mosaic BRAF fusions as recurrent drivers, MAPK/PI3K pathway crosstalk, epigenomic classification, and reports of NRAS amplification in NCM-associated melanoma. Though 2025, it aggregates 2023–2024 literature. (Salgado et al. 2025, Virchows Archiv, Jan 2025, https://doi.org/10.1007/s00428-024-04011-3) (salgado2025congenitalmelanocyticneoplasms pages 3-4, salgado2025congenitalmelanocyticneoplasms pages 10-11)
Current Applications and Real-World Implementations - Molecular diagnostics: hotspot testing for NRAS Q61 and BRAF V600 in CMN and associated tumors; fusion testing (BRAF, RAF1) in atypical cases; use of methylation profiling in challenging pediatric melanocytic neoplasms for classification. (salgado2025congenitalmelanocyticneoplasms pages 3-4, salgado2025congenitalmelanocyticneoplasms pages 10-11) - Imaging risk stratification: early-life brain/spine MRI in infants with large/giant CMN and multiple satellites to identify CNS melanocytosis and stratify risk. (basu2024therapeuticstrategiesin pages 2-3, salgado2025congenitalmelanocyticneoplasms pages 3-4) - Targeted therapy experience: case-level and small-series experience with MEK inhibition (e.g., trametinib) in NRAS-mutant CMN/NCM; combination strategies exploring MAPK plus epigenetic therapy (e.g., azacitidine) have shown transient responses with resistance. These approaches derive from the centrality of MAPK signaling and adaptive PI3K activation. (hamed2025oncogenicdriversand pages 40-44, basu2024therapeuticstrategiesin pages 2-3, salgado2025congenitalmelanocyticneoplasms pages 3-4)
Expert Opinions and Authoritative Analyses - Reviews emphasize that CMN-associated melanoma is mechanistically distinct from conventional UV-driven adult cutaneous melanoma, with early embryonic mosaic drivers (NRAS/BRAF) and lower UV-signature mutational contexts; progression relies on telomere, cell-cycle, and PI3K alterations, and epigenomic state. Interdisciplinary management, molecular testing, and surveillance are recommended, with research priorities in faithful modeling and rational combination therapy. (basu2024therapeuticstrategiesin pages 2-3, salgado2025congenitalmelanocyticneoplasms pages 3-4, kaminiow2025oncogenicspecificityin pages 2-3)
Relevant Statistics and Data - Driver prevalence: NRAS Q61 is dominant in large/giant CMN (≈68–77% in aggregated series; up to ~90% in the very largest lesions), while BRAF V600 is a minority driver; mosaic BRAF fusions/RAF1 fusions are rare but recurrent. (Salgado 2025; Kaminiow 2025) (salgado2025congenitalmelanocyticneoplasms pages 3-4, kaminiow2025oncogenicspecificityin pages 3-4) - NCM burden and outcomes: a meta-analysis summarized in a 2024 review reports leptomeningeal melanoma in a minority of NCM (≈9% of NCM overall), with most symptomatic NCM patients requiring shunting and experiencing poor survival; peritoneal seeding via VP shunt is a recognized complication. (Basu 2024) (basu2024therapeuticstrategiesin pages 2-3) - Risk stratification: early MRI abnormalities within the first months of life predict worse outcomes and higher childhood melanoma risk in giant CMN/NCM. (Salgado 2025; Basu 2024) (basu2024therapeuticstrategiesin pages 2-3, salgado2025congenitalmelanocyticneoplasms pages 1-3, salgado2025congenitalmelanocyticneoplasms pages 3-4)
Structured Knowledge Base Annotations - Genes/Proteins (HGNC): NRAS (HGNC:7989); BRAF (HGNC:1097); RAF1 (HGNC:9829); MAP2K1 (HGNC:6840); MAP2K2 (HGNC:6842); TERT (HGNC:11730); CDKN2A (HGNC:1787); TP53 (HGNC:11998); PTEN (HGNC:9588); MC1R (HGNC:6935); MET (HGNC:7029); HGF (HGNC:4886); GNAQ (HGNC:4399); GNA11 (HGNC:4380); S1PR3 (HGNC:3169). (salgado2025congenitalmelanocyticneoplasms pages 3-4, basu2024therapeuticstrategiesin pages 2-3, salgado2025congenitalmelanocyticneoplasms pages 10-11) - Biological Processes (GO): MAPK cascade (GO:0000165); positive regulation of ERK1/ERK2 cascade (GO:0070374); PI3K signaling (GO:0014065); G1/S transition of mitotic cell cycle (GO:0044843); regulation of telomere maintenance via telomerase (GO:1904356); cellular senescence (GO:0090398); melanocyte differentiation (GO:0030318); neural crest cell migration (GO:0014037); response to UV (GO:0009411); regulation of immune response (GO:0050776). (basu2024therapeuticstrategiesin pages 2-3, salgado2025congenitalmelanocyticneoplasms pages 3-4, salgado2025congenitalmelanocyticneoplasms pages 10-11) - Cellular Components (GO): plasma membrane (GO:0005886); cytosol (GO:0005829); nucleus (GO:0005634); chromatin (GO:0000785); telomere (GO:0000781); extracellular space (GO:0005615). (basu2024therapeuticstrategiesin pages 2-3, salgado2025congenitalmelanocyticneoplasms pages 3-4) - Cell Types (CL): melanocyte (CL:0000148); neural crest cell (CL:0000133); Schwann cell (CL:0002573); mast cell (CL:0000097); macrophage (CL:0000235). (salgado2025congenitalmelanocyticneoplasms pages 10-11) - Anatomical Locations (UBERON): skin (UBERON:0002097); epidermis (UBERON:0001003); dermis (UBERON:0002067); leptomeninx (UBERON:0002416); brain (UBERON:0000955). (basu2024therapeuticstrategiesin pages 2-3, salgado2025congenitalmelanocyticneoplasms pages 3-4) - Chemical Entities (CHEBI): trametinib (CHEBI:75962); azacitidine (CHEBI:47616); alpelisib (CHEBI:90684) [class exemplar for PI3K inhibition discussed]. (hamed2025oncogenicdriversand pages 40-44, salgado2025congenitalmelanocyticneoplasms pages 3-4) - Evidence items (selected, with URLs and publication dates): • Basu D. Therapeutic Strategies in Neurocutaneous Melanocytosis. AntiCancer Research. Dec 2024. https://doi.org/10.21873/anticanres.17341. (basu2024therapeuticstrategiesin pages 2-3) • Salgado CM, Tomás-Velázquez A, Reyes-Múgica M. Congenital melanocytic neoplasms: clinical, histopathological and recent molecular developments. Virchows Archiv. Jan 2025. https://doi.org/10.1007/s00428-024-04011-3. (salgado2025congenitalmelanocyticneoplasms pages 3-4, salgado2025congenitalmelanocyticneoplasms pages 10-11) • Kaminiow K, Ostrowski SM, Fisher DE. Oncogenic specificity in nevus and melanoma formation. Journal of Cancer Biology. Aug 2025. https://doi.org/10.46439/cancerbiology.6.075. (kaminiow2025oncogenicspecificityin pages 2-3, kaminiow2025oncogenicspecificityin pages 3-4) • Pellerino A, et al. Primary Meningeal Melanocytic Tumors… EURACAN. Cancers. Jul 2024. https://doi.org/10.3390/cancers16142508. (basu2024therapeuticstrategiesin pages 2-3) • Hamed E. Oncogenic drivers and therapeutic vulnerabilities in pediatric rhabdomyosarcoma and melanoma. 2025. (hamed2025oncogenicdriversand pages 40-44)
Notes on direct quotes - Wherever possible, claims are directly tied to peer-reviewed 2023–2024 reviews and primary reports. Direct quotations were limited by the retrieved excerpt format; verbatim diagnostic criteria and prevalence ranges are paraphrased with precise citations and URLs.
Conclusions Melanoma arising in CMN is a mosaic, developmentally rooted malignancy classically driven by NRAS Q61 (and less commonly BRAF V600 or BRAF/RAF1 fusions), converging on MAPK signaling with PI3K–AKT/mTOR cooperation. Progression requires senescence bypass (CDKN2A/TP53), telomere activation (TERT), and additional genomic/epigenomic changes, with neurotropic dissemination reflecting early neural crest lineage involvement. These mechanistic insights support risk stratification (early MRI), molecular diagnostics (NRAS/BRAF hotspots, fusions, methylation profiling), and rational targeted approaches (MEK ± PI3K/epigenetic combinations), though robust clinical evidence in NCM remains limited and outcomes poor, underscoring the need for prospective registries and trials. (basu2024therapeuticstrategiesin pages 2-3, salgado2025congenitalmelanocyticneoplasms pages 3-4, salgado2025congenitalmelanocyticneoplasms pages 10-11)
References
(basu2024therapeuticstrategiesin pages 2-3): DIPANJAN BASU. Therapeutic strategies in neurocutaneous melanocytosis. AntiCancer Research, 44:5157-5167, Dec 2024. URL: https://doi.org/10.21873/anticanres.17341, doi:10.21873/anticanres.17341. This article has 1 citations and is from a peer-reviewed journal.
(salgado2025congenitalmelanocyticneoplasms pages 3-4): Claudia Maria Salgado, Alejandra Tomás-Velázquez, and Miguel Reyes-Múgica. Congenital melanocytic neoplasms: clinical, histopathological and recent molecular developments. Virchows Archiv, 486:165-176, Jan 2025. URL: https://doi.org/10.1007/s00428-024-04011-3, doi:10.1007/s00428-024-04011-3. This article has 5 citations and is from a peer-reviewed journal.
(salgado2025congenitalmelanocyticneoplasms pages 1-3): Claudia Maria Salgado, Alejandra Tomás-Velázquez, and Miguel Reyes-Múgica. Congenital melanocytic neoplasms: clinical, histopathological and recent molecular developments. Virchows Archiv, 486:165-176, Jan 2025. URL: https://doi.org/10.1007/s00428-024-04011-3, doi:10.1007/s00428-024-04011-3. This article has 5 citations and is from a peer-reviewed journal.
(salgado2025congenitalmelanocyticneoplasms pages 10-11): Claudia Maria Salgado, Alejandra Tomás-Velázquez, and Miguel Reyes-Múgica. Congenital melanocytic neoplasms: clinical, histopathological and recent molecular developments. Virchows Archiv, 486:165-176, Jan 2025. URL: https://doi.org/10.1007/s00428-024-04011-3, doi:10.1007/s00428-024-04011-3. This article has 5 citations and is from a peer-reviewed journal.
(kaminiow2025oncogenicspecificityin pages 2-3): Konrad Kaminiow, Stephen M Ostrowski, and David E. Fisher. Oncogenic specificity in nevus and melanoma formation. Journal of Cancer Biology, 6:64-70, Aug 2025. URL: https://doi.org/10.46439/cancerbiology.6.075, doi:10.46439/cancerbiology.6.075. This article has 0 citations.
(kaminiow2025oncogenicspecificityin pages 3-4): Konrad Kaminiow, Stephen M Ostrowski, and David E. Fisher. Oncogenic specificity in nevus and melanoma formation. Journal of Cancer Biology, 6:64-70, Aug 2025. URL: https://doi.org/10.46439/cancerbiology.6.075, doi:10.46439/cancerbiology.6.075. This article has 0 citations.
(hamed2025oncogenicdriversand pages 40-44): E Hamed. Oncogenic drivers and therapeutic vulnerabilities in pediatric rhabdomyosarcoma and melanoma. Unknown journal, 2025.