A 66-year-old woman presents with massive splenomegaly and fatigue. Peripheral smear shows teardrop-shaped red cells, nucleated red cells, and early myeloid forms. Bone marrow aspiration yields a dry tap. Biopsy shows hypercellular marrow with clusters of atypical megakaryocytes and increased reticulin fibrosis. What is the most likely diagnosis?
- A Chronic myeloid leukemia, chronic phase
- B Primary myelofibrosis ✓
- C Myelodysplastic syndrome with fibrosis
- D Hairy cell leukemia
Correct answer: B. Primary myelofibrosis
Explanation
Primary myelofibrosis features megakaryocytic proliferation with atypical megakaryocytes driving reactive marrow fibrosis through release of fibrogenic cytokines such as TGF-beta and PDGF. Fibrosis causes the dry tap, extramedullary hematopoiesis causes hepatosplenomegaly, and the blood film shows leukoerythroblastosis with teardrop cells. Hairy cell leukemia also gives a dry tap, but hairy cells with TRAP positivity are seen, not teardrop cells and atypical megakaryocytes.
Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.