hematology and oncology
Primary Myelofibrosis (PMF)
Diagnosis of Primary Myelofibrosis
Complete blood count (CBC) and peripheral blood smear Bone marrow aspirate and biopsy Testing forJAK2,CALR, andMPLmutations Primary myelofibrosis should be suspected in patients with some combination of splenomegaly, splenic infarction, and unexplained anemia. If the disorder is suspected, CBC should be done and peripheral blood morphology and a bone marrow biopsy should be examined. If myelofibrosis is present on bone marrow aspirate and biopsy (as detected by reticulin staining or trichrome staining, indicating excess collagen and osteosclerosis), other disorders associated with myelofibrosis (see table) should be excluded by appropriate clinical and laboratory evaluation. The diagnosis of primary myelofibrosis is confirmed by detecting a mutation inJAK2,CALR, orMPL. In some cases, none of these mutations is expressed (triple-negative myelofibrosis). A broader next-generation sequencing panel may detect gene mutations associated with increased risk of leukemic transformation and may therefore be useful for prognosis. Anemia is typically present and usually increases over time. Blood cell morphology is variable. Red blood cells (RBCs) are poikilocytic. Reticulocytosis and polychromatophilia may be present; teardrop-shaped RBCs (dacryocytes) are characteristic morphologic features. Nucleated RBCs and neutrophil precursors are typically present in peripheral blood. White blood cell counts are usually increased but are highly variable. In advanced stages, myeloblasts may be present, even in the absence of acute leukemia. Platelet counts initially may be high, normal, or decreased; however, thrombocytopenia tends to supervene as the disorder progresses. 