Primary myelofibrosis
Primary myelofibrosis
Updated: 7/15/2019
© Jun Wang, MD, PhD
General features
- Clonal neoplastic transformation of hematopoietic stem cells
- Fibrosis caused by activation of background reactive fibroblasts
- More common in Caucasians, Ashkenazi Jews
Clinical presentations
- Anemia with teardrop-shaped RBCs
- Extramedullary hematopoiesis
- Leukoerythroblastosis: Nucleated erythroid and early granulocyte progenitors in peripheral blood, due to premature release
- Marked hepatosplenomegaly
- Dry tap: Failure to obtain bone marrow on attempted marrow aspiration
Key pathogenesis
- Megakaryocytes production of TGF-β, PDGF and bFGF
- Growth factors induce fibrosis and angiogenesis
Key Laboratory findings
- Anemia with teardrop-shaped RBCs
Key morphological features
- Progressive bone marrow fibrosis (arrow: megakaryocytes)
Genetic abnormalities
- Activation of JAK2, CALR, MPL
Differential diagnosis
- Other causes of leukoerythroblastosis or dry taps: Granulomatous marrow disease, metastases to marrow or hairy cell leukemia
- Polycythemia vera: Increased red cell mass
- Essential thrombocythemia: Marrow morphology
- Chronic myelogenous leukemia, BCR-ABL1–positive: BCR/ABL translocation
- Myelodysplastic syndrome (MDS): Dysplasia, especially dyserythropoiesis
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