Bone Marrow Morphology in Myeloproliferative Neoplasms – Relevance in the Molecular Era

Abstract

Background: Myeloproliferative neoplasms (MPNs) are clonal hematopoietic disorders. The mutation BCR-ABL is sine qua non for diagnosis of chronic myeloid leukemia and JAK2 V617F is present in majority of cases of polycythemia vera (PV), essential thrombocythemia (ET) and primary myelofibrosis (MF). Recent 2016 classification consigns importance to BM morphology as mutations are not universal. Identification of specific features would aid diagnosis of JAK2V617F negative MPN. This study aims to assess utility of peripheral blood and bone marrow morphology in myeloproliferative neoplasms in correlation with BCR-ABL and JAK2V617F. Methods: A retrospective 7 years study of peripheral blood, bone marrow aspirate (BMA) and bone marrow biopsy (BMB) of 44 cases of myeloproliferative neoplasms with BCR-ABL and JAK2 V617F mutation analysis. Results: Forty four cases of MPNs including 24 (54.5%) cases of CML, 7 (15.9% ) cases of PV, 5 (11.3%) cases of MF, 3 (6.8%) cases of ET, and 5 (11.3%) cases of MPN-U. MPV and LDH were significantly higher in MF in comparison to PV and ET. Higher haemoglobin (Hb) and platelets were seen in PV and ET. Dwarf MKs with hypolobated, cloud like nuclei in CML (fig 1), large MKs with staghorn nuclei were seen in ET. normal sized MKs with cloud like hypolobated forms in PV(fig2) and cloud like atypical dysmorphic nuclei with dense clustering were seen in MF. Conclusion: Hb, mean platelet volume (MPV), and LDH in conjunction with MK morphology aids in the diagnosis of MPNs. These findings will enable accurate diagnosis in JAK2 negative MPNs and benefit low resource center.