Home / Deep Research / Sea-Blue Histiocyte Syndrome

Sea-Blue Histiocyte Syndrome

1. Disease Information

2026-06-13
Falcon MONDO:0010017 Model: Edison Scientific Literature 36 citations

1. Disease Information

1.1 What is the disease? (overview; current understanding)

SBHS refers to the presence of “sea-blue histiocytes”—lipid-laden macrophages with deep blue/blue-green cytoplasmic granules on Romanowsky/May–Grünwald–Giemsa stains—typically identified in bone marrow and sometimes in liver/spleen/other tissues. (caetano2016anemiainvestigationreveals pages 3-4, caetano2016anemiainvestigationreveals pages 1-2, fernandez2023síndromedelhistiocito pages 1-3)

A key modern framing is that sea-blue histiocytosis often “may not carry any prognostic value” by itself and should be treated as a morphologic clue prompting evaluation for an underlying disorder (hematologic high-turnover states, lipid storage diseases, dyslipidemias, nutrition/drug exposures). (bhardwaj2020seabluehistiocytosis pages 3-4, bhardwaj2020seabluehistiocytosis pages 1-3)

1.2 Key identifiers (OMIM/Orphanet/ICD/MeSH/MONDO)

The retrieved primary texts and reviews did not provide OMIM/Orphanet/ICD/MeSH/MONDO identifiers specific to SBHS. Accordingly, these identifiers are not asserted here. (caetano2016anemiainvestigationreveals pages 3-4, caetano2016anemiainvestigationreveals pages 1-2)

Related, well-defined differential diagnoses (examples) referenced in the retrieved sources include Niemann–Pick disease spectrum disorders and Niemann–Pick disease type C (NP-C), which have established genetic/diagnostic frameworks in the literature. (tirelli2024thegeneticbasis pages 1-3, ferreira2017lysosomalstoragediseases pages 13-16, ferreira2017lysosomalstoragediseases pages 11-13)

1.3 Synonyms / alternative names

Common terms used across reports/reviews include: - Sea-blue histiocyte syndrome / sea-blue histiocytosis (euch2013seabluehistiocytessyndrome pages 1-2, caetano2016anemiainvestigationreveals pages 1-2) - Primary/idiopathic sea-blue histiocytosis (bhardwaj2020seabluehistiocytosis pages 3-4, caetano2016anemiainvestigationreveals pages 3-4) - Inherited lipemic splenomegaly (used as an alternative descriptor for a rare primary genetic phenotype in a subset of literature) (bhardwaj2020seabluehistiocytosis pages 3-4)

1.4 Evidence source type

Most SBHS knowledge in the retrieved corpus is derived from: - Case reports and case-based reviews (human clinical pathology) (gunay2012pulmonaryinvolvementin pages 1-3, euch2013seabluehistiocytessyndrome pages 1-2, caetano2016anemiainvestigationreveals pages 1-2, fernandez2023síndromedelhistiocito pages 1-3) - Broader lysosomal storage disease reviews (expert synthesis) that contextualize sea-blue histiocytes as a histologic clue (ferreira2017lysosomalstoragediseases pages 13-16, ferreira2017lysosomalstoragediseases pages 11-13)

2. Etiology

2.1 Disease causal factors (primary vs secondary)

Primary SBHS (rare/idiopathic): - Defined operationally when no associated cause is found despite a thorough evaluation. (caetano2016anemiainvestigationreveals pages 3-4, caetano2016anemiainvestigationreveals pages 5-6)

Secondary sea-blue histiocytosis (more common): documented associations include: - Lysosomal storage diseases (e.g., Gaucher disease, Niemann–Pick disorders) (bhardwaj2020seabluehistiocytosis pages 3-4, caetano2016anemiainvestigationreveals pages 3-4, euch2013seabluehistiocytessyndrome pages 1-2, ferreira2017lysosomalstoragediseases pages 13-16) - Hematologic disorders with increased marrow precursor turnover (e.g., myeloproliferative disease, myelodysplasia, ineffective erythropoiesis; even ITP as an incidental finding via rapid megakaryocytic turnover) (bhardwaj2020seabluehistiocytosis pages 3-4, bhardwaj2020seabluehistiocytosis pages 1-3) - Severe dyslipidemias / hypertriglyceridemia (bhardwaj2020seabluehistiocytosis pages 3-4, euch2013seabluehistiocytessyndrome pages 1-2) - Prolonged total parenteral nutrition (TPN)—documented as a real-world acquired cause (fernandez2023síndromedelhistiocito pages 1-3) - Drug/toxin exposures reported in the literature (e.g., liposomal amphotericin B mentioned in reviews) (bhardwaj2020seabluehistiocytosis pages 3-4, caetano2016anemiainvestigationreveals pages 4-5)

2.2 Genetic risk factors / Mendelian context (key genes)

The SBHS label itself is not tied to a single causal gene in the retrieved evidence; rather, sea-blue histiocytes appear in multiple Mendelian disorders.

Key Mendelian differentials and genes explicitly described in retrieved authoritative reviews: - Acid sphingomyelinase deficiency (ASMD; Niemann–Pick A/B): caused by SMPD1 mutations with lack of acid sphingomyelinase activity. (tirelli2024thegeneticbasis pages 1-3) - Niemann–Pick disease type C (NP-C): caused by NPC1 (majority) or NPC2 mutations, affecting intracellular cholesterol trafficking/esterification. (tirelli2024thegeneticbasis pages 1-3, ferreira2017lysosomalstoragediseases pages 13-16)

Sea-blue histiocytes specifically in Niemann–Pick context: a comprehensive lysosomal storage disease review captions a marrow image: “A sea-blue histiocyte is present in the marrow. These cells are predominantly seen in types C and F.” (ferreira2017lysosomalstoragediseases pages 11-13)

2.3 Environmental and iatrogenic contributors

A 2023 case report (Argentina) describes sea-blue histiocyte syndrome in bone marrow secondary to TPN, emphasizing lysosomal accumulation of oxidized lipids/lipoprotein material and reticuloendothelial deposition during prolonged lipid emulsion exposure. (fernandez2023síndromedelhistiocito pages 1-3)

3. Phenotypes (clinical features) and Ontology Suggestions

3.1 Core phenotypes (SBHS as a syndrome; primary cases)

From case-based reviews: - Splenomegaly is reported as the most consistent clinical finding in primary SBHS. (caetano2016anemiainvestigationreveals pages 4-5) - Hepatomegaly accompanies splenomegaly in ~60% of primary cases (reviewed in Caetano et al.). (caetano2016anemiainvestigationreveals pages 4-5) - Thrombocytopenia with hemorrhagic diathesis/purpura is part of the classic primary phenotype described in reviews. (bhardwaj2020seabluehistiocytosis pages 3-4, caetano2016anemiainvestigationreveals pages 4-5) - Hypertriglyceridemia is highlighted in the “primary genetic clinical syndrome” framing. (bhardwaj2020seabluehistiocytosis pages 3-4) - Cytopenias (including pancytopenia) can occur (reported across cases). (euch2013seabluehistiocytessyndrome pages 1-2, fernandez2023síndromedelhistiocito pages 1-3)

3.2 Secondary/associated phenotypes (depend on underlying cause)

3.3 Suggested HPO terms (examples; for knowledge base structuring)

(Provided as ontology suggestions consistent with described findings; not asserted as exhaustive) - Splenomegaly (HP:0001744) - Hepatomegaly (HP:0002240) - Thrombocytopenia (HP:0001873) - Pancytopenia (HP:0001876) - Anemia (HP:0001903) - Hypertriglyceridemia (HP:0002155) - Hepatic failure (HP:0001410) / Cirrhosis (HP:0001394) - Pulmonary infiltrates / interstitial lung disease (context-dependent; e.g., HP:0006530)

3.4 Quality-of-life impact

No SBHS-specific validated QoL instruments or quantitative QoL data were present in the retrieved texts. Clinical impact is inferred through organomegaly, cytopenias, bleeding risk, and (in severe cases) liver failure/multiorgan dysfunction. (caetano2016anemiainvestigationreveals pages 3-4, fernandez2023síndromedelhistiocito pages 1-3)

4. Genetic/Molecular Information

4.1 Causal genes for SBHS

Not established as a single-gene disorder in the retrieved evidence. SBHS is best treated as a pattern that can arise from diverse causes. (bhardwaj2020seabluehistiocytosis pages 3-4, caetano2016anemiainvestigationreveals pages 3-4)

4.2 Mendelian disorders where sea-blue histiocytes are a diagnostic clue

4.3 Variant-level data, allele frequencies, modifier genes

No SBHS-specific variant cataloging (ClinVar-style) or allele frequency data were present in retrieved SBHS-focused case reports/reviews. For the Niemann–Pick disorders, gene-level causation is stated in a 2024 review (SMPD1; NPC1/NPC2), but specific variant spectra were not extracted from the retrieved pages. (tirelli2024thegeneticbasis pages 1-3)

5. Environmental Information

5.1 Environmental/lifestyle factors

SBHS is not presented as a lifestyle-mediated disease entity in the retrieved evidence. However, iatrogenic lipid exposure via prolonged TPN is a documented acquired contributor. (fernandez2023síndromedelhistiocito pages 1-3)

5.2 Infectious triggers

Not a primary theme for SBHS in the retrieved literature; however, secondary sea-blue histiocytes may be encountered in broad hematologic/inflammatory contexts depending on underlying disease. (bhardwaj2020seabluehistiocytosis pages 3-4)

6. Mechanism / Pathophysiology

6.1 Key concept: what are sea-blue granules?

Multiple sources converge on the concept that sea-blue histiocytes are macrophages with lysosomal accumulation of lipid-derived material, including oxidized, indigestible lipid/lipoprotein material with ceroid-like features. - Fernández et al. (2023) abstract: sea-blue histiocytes are “macrophages laden with phospholipid granules … granules result from lysosomal accumulation of indigestible oxidized lipid or lipoprotein material.” (fernandez2023síndromedelhistiocito pages 1-3) - Bhardwaj et al. (2020) describes the blue material as ceroid derived from oxidation/polymerization of unsaturated lipids. (bhardwaj2020seabluehistiocytosis pages 3-4)

6.2 Causal chain (high-level)

  1. Upstream trigger (examples):
  2. Increased intramedullary cell death/turnover (myeloproliferation, ineffective erythropoiesis) (bhardwaj2020seabluehistiocytosis pages 3-4)
  3. Primary lipid trafficking/lysosomal dysfunction (e.g., NP-C; ASMD) (tirelli2024thegeneticbasis pages 1-3, ferreira2017lysosomalstoragediseases pages 13-16)
  4. Prolonged exposure to intravenous lipid emulsions (TPN-associated acquired form) (fernandez2023síndromedelhistiocito pages 1-3)
  5. Macrophage processing overload / lysosomal lipid accumulation → formation of pigmented granules (ceroid/lipofuscin-like) (caetano2016anemiainvestigationreveals pages 4-5, fernandez2023síndromedelhistiocito pages 1-3)
  6. Tissue infiltration (marrow ± liver/spleen/lymphoid organs/lung) → clinical manifestations: cytopenias (marrow involvement/hypersplenism), organomegaly, hypertriglyceridemia in some primary phenotypes, and liver dysfunction in severe cases. (caetano2016anemiainvestigationreveals pages 4-5, caetano2016anemiainvestigationreveals pages 3-4, fernandez2023síndromedelhistiocito pages 1-3)

6.3 Suggested GO terms (examples)

  • GO:0006629 lipid metabolic process
  • GO:0006897 endocytosis
  • GO:0005764 lysosome (cellular component)
  • GO:0030198 extracellular matrix organization (if fibrosis/cirrhosis mechanisms are being captured downstream)
  • GO:0006954 inflammatory response (when associated with immune/hematologic conditions)

6.4 Suggested Cell Ontology (CL) terms

7. Anatomical Structures Affected

7.1 Organ/tissue distribution

7.2 Suggested UBERON terms (examples)

7.3 Subcellular localization

8. Temporal Development (onset and progression)

9. Inheritance and Population

9.1 Inheritance

9.2 Epidemiology

Robust SBHS-specific incidence/prevalence estimates were not present in the retrieved SBHS-focused papers.

Useful contextual statistics from authoritative reviews: - Lysosomal storage diseases (as a group): “collective incidence of 1 in 5000 live births.” (Serrano et al., published 2 Mar 2024; https://doi.org/10.3390/jcm13051465) (serrano2024hepatomegalyandsplenomegaly pages 1-2) - NP-C prevalence: approximately 1 in 150,000 (Ferreira & Gahl 2017; https://doi.org/10.3233/TRD-160005). (ferreira2017lysosomalstoragediseases pages 13-16)

10. Diagnostics (current practice and real-world implementation)

10.1 Pathology / morphology (core diagnostic clue)

Visual evidence (bone marrow sea-blue histiocytes): Fernández et al. (2023) includes marrow image panels showing macrophages with blue cytoplasmic granules consistent with sea-blue histiocytes in TPN-associated acquired syndrome. (fernandez2023síndromedelhistiocito media 38826773, fernandez2023síndromedelhistiocito media 3a59548e)

10.2 Differential diagnosis (must be pursued)

Finding sea-blue histiocytes should trigger evaluation for: - Hematologic malignancy / myelodysplasia / myeloproliferation (bhardwaj2020seabluehistiocytosis pages 3-4) - Lysosomal storage diseases (e.g., Niemann–Pick, Gaucher; NP-C) (caetano2016anemiainvestigationreveals pages 3-4, ferreira2017lysosomalstoragediseases pages 13-16) - Dyslipidemias (e.g., severe hypertriglyceridemia) (bhardwaj2020seabluehistiocytosis pages 3-4, euch2013seabluehistiocytessyndrome pages 1-2) - TPN exposure and medications associated with acquired lipidosis (bhardwaj2020seabluehistiocytosis pages 3-4, fernandez2023síndromedelhistiocito pages 1-3)

10.3 Laboratory and molecular testing (modern approach)

A major shift in the broader storage-disease diagnostic paradigm is toward molecular confirmation: - Serrano et al. (2024) abstract: “molecular testing, arguably the preferred confirmatory test (over biopsy), accompanied by enzymatic testing when feasible.” (serrano2024hepatomegalyandsplenomegaly pages 1-2)

For NP-C specifically (as a key Mendelian differential): - Ferreira & Gahl (2017) highlights biochemical markers such as plasma oxysterols (cholestane-3,5,6-triol; 7-ketocholesterol) and describes fibroblast-based filipin testing as available in some labs, with increasing reliance on molecular testing. (ferreira2017lysosomalstoragediseases pages 13-16)

For Niemann–Pick/ASMD and NP-C (2024 expert review): - Tirelli et al. (published 11 Feb 2024; https://doi.org/10.3390/biom14020211) explicitly states genetic bases (SMPD1; NPC1/NPC2) and indicates bronchoscopy/BAL/biopsy and HRCT as key tools for pulmonary assessment when relevant. (tirelli2024thegeneticbasis pages 1-3)

11. Outcome / Prognosis

12. Treatment

12.1 SBHS-directed therapy

SBHS itself generally has no specific treatment, other than management of the underlying disorder when identified. (caetano2016anemiainvestigationreveals pages 3-4)

12.2 Disease-specific therapies relevant to key Mendelian differentials

From a 2024 comprehensive Niemann–Pick review: - ASMD (SMPD1-related): “Enzyme replacement therapy with Olipudase α is the first and only approved disease-modifying therapy for patients with ASMD.” (tirelli2024thegeneticbasis pages 1-3) - NP-C (NPC1/NPC2-related): “The only approved disease-modifying therapy in NPD type C is miglustat, a substrate-reduction treatment.” (tirelli2024thegeneticbasis pages 1-3)

12.3 Supportive care / complication management

  • Cytopenia management, bleeding risk mitigation, and management of organ complications (e.g., liver disease; pulmonary involvement when present). (gunay2012pulmonaryinvolvementin pages 1-3, fernandez2023síndromedelhistiocito pages 1-3)

12.4 Suggested MAXO terms (examples)

  • Enzyme replacement therapy (MAXO term; for ASMD/olipudase alfa context)
  • Substrate reduction therapy (MAXO term; for miglustat in NP-C)
  • Genetic counseling (MAXO)
  • Lipid-lowering therapy (MAXO; for dyslipidemia-associated forms)
  • Parenteral nutrition modification (MAXO; for TPN-associated acquired form)

13. Prevention

  • Primary prevention is not defined for SBHS as a heterogeneous pattern.
  • Secondary/tertiary prevention focuses on early recognition of the marrow finding, prompt etiologic workup, and early initiation of disease-modifying therapy where available for underlying Mendelian disorders (e.g., ASMD, NP-C), consistent with the broader LSD literature emphasizing early diagnosis and targeted management. (serrano2024hepatomegalyandsplenomegaly pages 1-2, tirelli2024thegeneticbasis pages 1-3)
  • For iatrogenic acquired forms (e.g., TPN-associated), prevention/mitigation may include lipid formulation/dose adjustments and monitoring for hepatic and hematologic complications. (fernandez2023síndromedelhistiocito pages 1-3)

14. Other Species / Natural Disease

No non-human natural disease evidence for “sea-blue histiocyte syndrome” was present in the retrieved texts.

15. Model Organisms

No SBHS-specific model organism systems were described in the retrieved texts. Mechanistic and model-organism work is more developed for underlying Mendelian lysosomal storage diseases (e.g., NP-C), but those details were not extracted in the retrieved evidence set.

Recent Developments (prioritizing 2023–2024)

  1. Real-world acquired SBHS linked to parenteral nutrition (case report, 2023): provides a contemporary, clinically actionable example of secondary sea-blue histiocytosis and includes marrow pathology images. (Fernández et al., received 29 Mar 2023; approved 30 May 2023; published 2023; https://doi.org/10.48057/hematologa.v27i2.519) (fernandez2023síndromedelhistiocito pages 1-3, fernandez2023síndromedelhistiocito media 38826773, fernandez2023síndromedelhistiocito media 3a59548e)
  2. Modern genetic/therapeutic framing in Niemann–Pick disorders (review, published Feb 2024): clarifies gene causation (SMPD1; NPC1/NPC2) and states approved disease-modifying therapies (olipudase alfa for ASMD; miglustat for NP-C), providing an up-to-date expert synthesis relevant to SBHS differential diagnosis. (Tirelli et al., published 11 Feb 2024; https://doi.org/10.3390/biom14020211) (tirelli2024thegeneticbasis pages 1-3)
  3. Contemporary diagnostic philosophy for hepatosplenomegaly/LSDs (review, published Mar 2024): emphasizes that molecular testing is now commonly preferred over biopsy for confirmation in suspected LSDs, which directly impacts how a sea-blue histiocyte finding should be followed up. (Serrano et al., published 2 Mar 2024; https://doi.org/10.3390/jcm13051465) (serrano2024hepatomegalyandsplenomegaly pages 1-2)

Expert opinions & analysis (authoritative synthesis)

  • SBHS as a marker rather than a stand-alone disease: The Cureus case-based discussion stresses sea-blue histiocytosis is often an “unusual bone marrow finding” and should prompt evaluation for underlying disorders (myelodysplasia, infiltrative disease, storage disease, high turnover states). (bhardwaj2020seabluehistiocytosis pages 3-4)
  • Niemann–Pick/NP-C diagnostic caution: A highly cited lysosomal storage disease review notes sea-blue histiocytes can be present in NP-C but are not specific, and may be absent without visceromegaly—supporting the need for biochemical/molecular confirmation. (ferreira2017lysosomalstoragediseases pages 13-16, ferreira2017lysosomalstoragediseases pages 16-19)

Evidence Table (cross-walk summary)

Table (click to expand)
Topic Summary of finding Key genes/disorders in context Diagnostic tests / pathology clues Key statistics Source (year) DOI / URL Evidence
Histologic definition of sea-blue histiocytes Sea-blue histiocytes are lipid-laden macrophages with deep blue/blue-green cytoplasmic granules on Romanovsky or May-Grünwald-Giemsa stain; granules reflect lysosomal accumulation of oxidized indigestible lipid/lipoprotein material. Morphologic finding rather than a single-gene disease entity Bone marrow aspirate/biopsy; Giemsa stain; PAS and Sudan stains may be positive; autofluorescence and birefringence reported in reviews/case reports No disease-specific prevalence available Caetano 2016; Fernández 2023 https://doi.org/10.23937/2469-5807/1510019 ; https://doi.org/10.48057/hematologa.v27i2.519 (caetano2016anemiainvestigationreveals pages 1-2, caetano2016anemiainvestigationreveals pages 4-5, fernandez2023síndromedelhistiocito pages 1-3)
Primary vs secondary concept Primary/idiopathic SBHS is rare; secondary sea-blue histiocytosis is more common and occurs with hematologic disorders, lipid storage diseases, hypertriglyceridemia, parenteral nutrition, and drug/toxic exposures. Bhardwaj emphasizes it often “does not signify a distinct entity” but a morphologic marker of underlying disease/high marrow turnover. Primary SBHS; secondary forms linked to Niemann-Pick, Gaucher, LCAT deficiency, hyperlipoproteinemia, myeloproliferative disorders, ITP Requires exclusion workup for storage disease, hematologic neoplasm, ineffective erythropoiesis, nutrition/drug causes Primary form is rare; no robust prevalence estimate found Bhardwaj 2020; Caetano 2016; El Euch 2013 https://doi.org/10.7759/cureus.10396 ; https://doi.org/10.23937/2469-5807/1510019 ; https://doi.org/10.4236/ojim.2013.31005 (bhardwaj2020seabluehistiocytosis pages 3-4, bhardwaj2020seabluehistiocytosis pages 1-3, caetano2016anemiainvestigationreveals pages 3-4, euch2013seabluehistiocytessyndrome pages 1-2)
Typical clinical phenotype in reported primary SBHS Most consistent reported features are splenomegaly, often hepatomegaly, thrombocytopenia/hemorrhagic diathesis; pancytopenia can occur. Hypertriglyceridemia is part of the classic primary syndrome description. Primary SBHS phenotype; inherited lipemic splenomegaly concept Clinical exam plus CBC, lipid profile, liver studies; marrow biopsy often prompted by cytopenias/splenomegaly Hepatomegaly reported in ~60% of primary cases in review literature Caetano 2016; Bhardwaj 2020 https://doi.org/10.23937/2469-5807/1510019 ; https://doi.org/10.7759/cureus.10396 (caetano2016anemiainvestigationreveals pages 4-5, bhardwaj2020seabluehistiocytosis pages 3-4)
Reported prognosis in primary SBHS literature Course is usually benign/chronic, but severe organ infiltration can occur; fatal liver failure/cirrhosis is the major feared complication in older primary SBHS literature. Primary SBHS Monitor liver involvement, cytopenias, organomegaly Roughly 15% of cases reported to develop fatal liver failure/cirrhosis Caetano 2016; Fernández 2023; El Euch 2013 https://doi.org/10.23937/2469-5807/1510019 ; https://doi.org/10.48057/hematologa.v27i2.519 ; https://doi.org/10.4236/ojim.2013.31005 (caetano2016anemiainvestigationreveals pages 3-4, fernandez2023síndromedelhistiocito pages 1-3, euch2013seabluehistiocytessyndrome pages 1-2)
Niemann-Pick / ASMD context Sea-blue histiocytes are strongly associated with Niemann-Pick spectrum disorders in pathology practice. Older literature proposed “type F”/sea-blue histiocytosis for a relatively benign form without neurologic involvement, but this designation has fallen out of favor. SMPD1-related acid sphingomyelinase deficiency (ASMD/NPD A/B); historical NPD “type F” Bone marrow, liver, spleen, lung pathology may show foamy histiocytes/sea-blue histiocytes NPD types A/B combined prevalence in review excerpt ~1 in 250,000; historical type F label no longer favored Ferreira & Gahl 2017; Günay 2012; Tirelli 2024 https://doi.org/10.3233/trd-160005 ; https://doi.org/10.5578/tt.2215 ; https://doi.org/10.3390/biom14020211 (ferreira2017lysosomalstoragediseases pages 11-13, ferreira2017lysosomalstoragediseases pages 9-11, gunay2012pulmonaryinvolvementin pages 1-3, tirelli2024thegeneticbasis pages 1-3)
Niemann-Pick type C context In NP-C, pathology may include foam cells or sea-blue histiocytes in many tissues, but these are not specific and may be absent if visceromegaly is lacking; modern diagnosis relies on molecular and biochemical testing. NPC1, NPC2 Marrow/spleen biopsy can support suspicion; filipin-cholesterol staining in cultured fibroblasts; plasma oxysterols by LC-MS/MS; molecular testing NP-C prevalence ~1 in 150,000 Ferreira & Gahl 2017 https://doi.org/10.3233/trd-160005 (ferreira2017lysosomalstoragediseases pages 13-16, ferreira2017lysosomalstoragediseases pages 16-19)
ASMD genetics and modern therapy context ASMD/NPD A and B are autosomal recessive disorders due to SMPD1 mutations causing acid sphingomyelinase deficiency; olipudase alfa is the first approved disease-modifying therapy. This is relevant because sea-blue histiocytes can be a marrow/tissue clue to underlying ASMD. SMPD1 Enzyme assay for acid sphingomyelinase; molecular confirmation; HRCT/BAL/biopsy for lung disease when indicated No SBHS-specific treatment; ASMD has disease-modifying therapy Tirelli 2024 https://doi.org/10.3390/biom14020211 (tirelli2024thegeneticbasis pages 1-3)
Other associated disorders Reviews/case reports list Gaucher disease, LCAT deficiency, cholesterol ester storage disease, Tangier disease, severe hypertriglyceridemia/hyperlipoproteinemia, chronic myelogenous leukemia, myelodysplastic syndromes, thalassemia, ITP, and prolonged total parenteral nutrition as associations. Gaucher (GBA context not detailed in gathered evidence), LCAT deficiency, lipid disorders, hematologic disorders Directed enzyme assays, lipid studies, hematology workup, marrow review, medication/nutrition history No unified frequency across causes Caetano 2016; El Euch 2013; Bhardwaj 2020; Fernández 2023 https://doi.org/10.23937/2469-5807/1510019 ; https://doi.org/10.4236/ojim.2013.31005 ; https://doi.org/10.7759/cureus.10396 ; https://doi.org/10.48057/hematologa.v27i2.519 (caetano2016anemiainvestigationreveals pages 3-4, euch2013seabluehistiocytessyndrome pages 1-2, bhardwaj2020seabluehistiocytosis pages 3-4, fernandez2023síndromedelhistiocito pages 1-3)
Parenteral nutrition–associated acquired sea-blue histiocytosis 2023 case report documents marrow sea-blue histiocytes in a patient on prolonged parenteral nutrition, supporting a real-world acquired form due to abnormal long-chain fatty acid/lipid handling and reticuloendothelial deposition. Acquired/non-Mendelian mimic of SBHS Bone marrow aspirate/biopsy showed macrophages with blue intracytoplasmic granules; clinical correlation with liver failure, hypertriglyceridemia, pancytopenia Hypertriglyceridemia in case: 332 mg/dL; ferritin >1500 ng/mL Fernández 2023 https://doi.org/10.48057/hematologa.v27i2.519 (fernandez2023síndromedelhistiocito pages 1-3, fernandez2023síndromedelhistiocito media 38826773, fernandez2023síndromedelhistiocito media 3a59548e)
Practical diagnostic approach Current reviews on hepatosplenomegaly/LSDs recommend molecular testing as the preferred confirmatory test over biopsy when LSD is suspected, usually accompanied by enzymatic testing when feasible; biopsy remains useful as a clue when sea-blue histiocytes are discovered unexpectedly. LSD differential includes NPC, ASMD, Gaucher, CESD Imaging for hepatosplenomegaly; CBC/liver tests; molecular testing; enzyme testing; biopsy as supportive rather than definitive in many LSDs LSD collective incidence ~1 in 5000 live births Serrano 2024; Ferreira & Gahl 2017 https://doi.org/10.3390/jcm13051465 ; https://doi.org/10.3233/trd-160005 (serrano2024hepatomegalyandsplenomegaly pages 1-2, ferreira2017lysosomalstoragediseases pages 13-16, ferreira2017lysosomalstoragediseases pages 1-3)
Pulmonary/visceral involvement Sea-blue histiocytes/foamy macrophages can infiltrate liver, spleen, marrow, lung, and lymphoid organs; pulmonary involvement is uncommon in primary sea-blue histiocytosis but recognized in Niemann-Pick/ASMD. Particularly ASMD/Niemann-Pick; historical primary SBHS reports BAL, lung biopsy, HRCT, pulmonary function testing in symptomatic patients No general percentage reported; lung disease more frequent in NPD type B than C Günay 2012; Tirelli 2024; Fernández 2023 https://doi.org/10.5578/tt.2215 ; https://doi.org/10.3390/biom14020211 ; https://doi.org/10.48057/hematologa.v27i2.519 (gunay2012pulmonaryinvolvementin pages 1-3, tirelli2024thegeneticbasis pages 1-3, fernandez2023síndromedelhistiocito pages 1-3)

Table: This table consolidates the gathered evidence on Sea-Blue Histiocyte Syndrome/sea-blue histiocytosis, emphasizing that it is primarily a histopathologic pattern with a rare primary syndrome and many secondary causes. It also links the finding to modern lysosomal disease diagnostics and therapies relevant to the differential diagnosis.

Direct abstract quotes (selected)

  • Fernández et al. 2023 (TPN-associated acquired SBHS): “They are macrophages laden with phospholipid granules that stain dark blue with the May-Grünwald-Giemsa stain. These granules result from lysosomal accumulation of indigestible oxidized lipid or lipoprotein material.” (https://doi.org/10.48057/hematologa.v27i2.519; 2023) (fernandez2023síndromedelhistiocito pages 1-3)

  • Tirelli et al. 2024 (Niemann–Pick genetics/therapy): “NPD type A and B are caused by mutations in the gene SMPD1 … NPD type C is a neurologic disorder due to mutations in the genes NPC1 or NPC2 … Enzyme replacement therapy with Olipudase α is the first and only approved disease-modifying therapy for patients with ASMD … The only approved disease-modifying therapy in NPD type C is miglustat.” (https://doi.org/10.3390/biom14020211; published 11 Feb 2024) (tirelli2024thegeneticbasis pages 1-3)

  • Serrano et al. 2024 (HSM/LSD diagnostic approach): “lysosomal storage diseases (LSDs) are a group of rare and ultrarare conditions with a collective incidence of 1 in 5000 live births … we discuss molecular testing, arguably the preferred confirmatory test (over biopsy), accompanied by enzymatic testing when feasible.” (https://doi.org/10.3390/jcm13051465; published 2 Mar 2024) (serrano2024hepatomegalyandsplenomegaly pages 1-2)

Key data points (recent and/or quantitative)

Limitations of this evidence set

  • SBHS-specific standardized disease identifiers (MONDO/Orphanet/MeSH/ICD) and SBHS-specific causal genes/variant spectra were not present in the retrieved full-text excerpts, so they are not inferred here.
  • Much of SBHS literature is case-based; therefore, quantitative penetrance/expressivity and high-quality epidemiology are limited in the accessible sources.

References

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  16. (fernandez2023síndromedelhistiocito media 38826773): D. Fernández, D. Maymó, and G. Alfonso. Síndrome del histiocito azul marino en médula ósea secundario a nutrición parenteral total. reporte de un caso. Revista Hematología, 27:44-48, Sep 2023. URL: https://doi.org/10.48057/hematologa.v27i2.519, doi:10.48057/hematologa.v27i2.519. This article has 0 citations.

  17. (fernandez2023síndromedelhistiocito media 3a59548e): D. Fernández, D. Maymó, and G. Alfonso. Síndrome del histiocito azul marino en médula ósea secundario a nutrición parenteral total. reporte de un caso. Revista Hematología, 27:44-48, Sep 2023. URL: https://doi.org/10.48057/hematologa.v27i2.519, doi:10.48057/hematologa.v27i2.519. This article has 0 citations.

  18. (ferreira2017lysosomalstoragediseases pages 9-11): Carlos R. Ferreira and William A. Gahl. Lysosomal storage diseases. Translational Science of Rare Diseases, 2:1-71, Sep 2017. URL: https://doi.org/10.3233/trd-160005, doi:10.3233/trd-160005. This article has 435 citations.

  19. (ferreira2017lysosomalstoragediseases pages 1-3): Carlos R. Ferreira and William A. Gahl. Lysosomal storage diseases. Translational Science of Rare Diseases, 2:1-71, Sep 2017. URL: https://doi.org/10.3233/trd-160005, doi:10.3233/trd-160005. This article has 435 citations.

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