PVSG and WHO vs European Clinical, Molecular and Pathological Criteria for prefibrotic myeloproliferative neoplasms

Figure 3 Bone marrow histology features in essential thrombocythemia and polycythemia vera patients. A: Normocellular essential thrombocythemia (ET) bone marrow histology [World Health Organization (WHO)-ET] with increase of clustered pleomorphic megakaryocytes similar as in prodromal and overt polycythemia vera (PV); B: ET/PV bone marrow histology with pleomorphic megakaryocytes and increased cellularity due to increased erythropoiesis as can be seen in WHO and European Clinical, Molecular and Pathological defined prodromal PV and overt PV patients; C: PV bone marrow histology with increased cellularity due to increased erythropoiesis/granulopoiesis and increase of clustered pleomorphic megakaryocytes and no increase of reticulin fibrosis; D: Advanced PV bone marrow histology with dense clustered pleomorphic/dysmorphic megakaryocytes (not cloud-like) and increase in reticulin fibrosis grade 2.