Differential diagnosis of BCR-ABL1-negative myeloproliferative neoplasms

Abstract

Myeloproliferative neoplasms (MPN) are clonal stem cell disorders presenting with a broad spectrum of changes in bone marrow morphology, clinical findings, and overall outcome. The differential diagnosis between the three classical BCR-ABL1-negative subtypes essential thrombocythemia, polycythemia vera, and primary myelofibrosis may be difficult and should be based on the current diagnostic criteria proposed by the WHO. In this regard the discovery of new molecular markers as calreticulin (CALR) enables a better discrimination of reactive changes, however, mutation screening alone does not increase diagnostic specificity and subtyping of MPN. Therefore, in early stages of MPN which may present with a sustained thrombocytosis, a synoptical diagnostic approach with inclusion of hematological, molecular, cytological, and in particular histomorphological findings is essential.