The case represents primary myelofibrosis (PMF), where the marrow is still cellular. PMF is a clonal myeloproliferative neoplasm. Peripheral blood typically shows leukoerythroblastosis and anisopoikilocytosis. Constitutional symptoms, anemia, leukocytosis, and thrombocytosis, are frequent presenting features. Splenomegaly is seen in a majority of patients, and hepatomegaly is also frequent. In the early stages of PMF, the bone marrow is mostly hypercellular with prominence of myeloid lineage cells, which are left-sifted. Megakaryocytes are markedly abnormal with frequent presence of large cells with hyperchromatic or hyperlobated nuclei. JAK2-V617F mutation is seen in ∼50% patients. A systematic approach is essential for the diagnosis of these bone marrow trephine biopsies .
Diagnosis and classification of early stages of myeloproliferative neoplasms is challenging and has been addressed in a recent review .