Polycythemia vera: New clinicopathologic perspectives

Context. - Polycythemia vera (PV) is a clonal myeloproliferative disease characterized by an erythroid dominant trilineage proliferation of hematopoietic precursor cells. Classified as a chronic myeloproliferative disease, PV represents a histopathologic spectrum of 2 recognized stages, the polycythemic and postpolycythemic phase. The clinical manifestations of hemorrhage, thrombosis, and increased red cell mass are directly related to primary bone marrow dysfunction. Prognosis is strongly associated with thrombosis risk and disease progression; thus, treatment is directed toward minimizing coagulopathic complications and preventing leukemic transformation. Recently, a specific point mutation in the Janus kinase 2 (JAK2) gene was described in a majority of PV patients. The potential diagnostic and/or prognostic value of JAK2 ^V617F is discussed. Objective. - To review important developments from the recent and historical literature. Modern diagnostic criteria and emerging molecular findings are emphasized. Data Sources. - A comprehensive review was performed of the relevant literature indexed in PubMed (National Library of Medicine) and referenced medical texts. Conclusions. - Modified clinical, histologic, and laboratory criteria have clarified the diagnosis of PV. Also, continuing studies on the recently discovered JAK2^V617F gene mutation may significantly improve our understanding of PV pathogenesis and facilitate its medical management.