What is the most likely diagnosis and recommended management for a 17‑year‑old adolescent presenting with pancytopenia, massive splenomegaly, normocellular bone marrow, stunted growth, and characteristic facial dysmorphism?

Gaucher Disease Type 1

This 17-year-old with pancytopenia, massive splenomegaly, normocellular bone marrow, stunted growth, and facial dysmorphism most likely has Gaucher disease, and should undergo enzyme replacement therapy (ERT) with imiglucerase or velaglucerase alfa as first-line treatment.

Clinical Reasoning

The constellation of findings points away from myelodysplastic syndrome (MDS) and toward an inherited bone marrow failure syndrome or storage disorder:

Key Distinguishing Features

Why this is NOT MDS:

• The provided MDS guidelines 1 focus on adult patients with clonal hematopoiesis
• MDS rarely presents with massive splenomegaly
• Normocellular bone marrow is atypical for MDS
• The combination of stunted growth and facial dysmorphism suggests a congenital/inherited condition
• Age 17 with these specific dysmorphic features is inconsistent with typical MDS presentation

Why this suggests Gaucher Disease:

• Massive splenomegaly with pancytopenia is the hallmark presentation
• Normocellular bone marrow despite peripheral cytopenias indicates sequestration/hypersplenism rather than marrow failure
• Stunted growth occurs due to chronic disease burden and skeletal involvement
• Facial dysmorphism in Gaucher disease includes characteristic features
• This age group (adolescent) is typical for Type 1 Gaucher disease presentation

Alternative Considerations from Evidence

The evidence mentions inherited bone marrow failure syndromes 2, 3:

Fanconi Anemia typically presents with:

• Hypocellular bone marrow (NOT normocellular)
• Characteristic physical abnormalities (thumb hypoplasia, café-au-lait spots)
• Chromosome breakage testing is diagnostic 4, 3

Other inherited BMF syndromes 2:

• Dyskeratosis congenita: nail dystrophy, oral leukoplakia, pulmonary fibrosis
• Shwachman-Diamond syndrome: exocrine pancreatic insufficiency
• Diamond-Blackfan anemia: isolated anemia, not pancytopenia

Recommended Diagnostic Workup

1. Immediate testing:

   • Glucocerebrosidase enzyme activity assay (definitive for Gaucher)
   • Chitotriosidase levels (elevated in Gaucher)
   • Bone marrow aspirate review for Gaucher cells (lipid-laden macrophages)

2. If Gaucher excluded:

   • Chromosome breakage test with diepoxybutane (DEB) or mitomycin C for Fanconi anemia 4, 3
   • Genetic panel for inherited BMF syndromes 4, 5
   • Flow cytometry for paroxysmal nocturnal hemoglobinuria

3. Imaging:

   • Skeletal survey for bone involvement
   • Liver assessment for hepatomegaly

Management Algorithm

For Gaucher Disease (most likely):

• Enzyme replacement therapy: Imiglucerase 60 units/kg IV every 2 weeks OR velaglucerase alfa
• Monitor response: hemoglobin, platelet count, spleen size, bone pain
• Lifelong therapy required
• Excellent prognosis with treatment

If Fanconi Anemia confirmed:

• Refer for allogeneic hematopoietic stem cell transplantation evaluation 4
• Avoid DNA-damaging agents
• Cancer surveillance protocol
• Genetic counseling for family

If other inherited BMF:

• Syndrome-specific management per genetic diagnosis 5, 2
• Consider transplant candidacy based on specific condition

Critical Pitfalls to Avoid

• Do not treat as MDS without excluding inherited conditions in this age group
• Do not perform splenectomy before establishing diagnosis (can worsen outcomes in some storage diseases)
• Do not delay genetic/metabolic testing while pursuing extensive hematologic workup
• Do not assume acquired aplastic anemia with normocellular marrow and massive splenomegaly

The normocellular bone marrow is the critical clue that distinguishes this from typical bone marrow failure syndromes and points toward a sequestration/storage disorder rather than a production problem.