Current Trends in the Diagnosis and Evidence-Based Management of Patients with Myeloproliferative Disorders

Myeloproliferative disorders (MPD) are clonal hematopoietic disorders characterized by abnormal clone expansion of haematological progenitor cells, which can lead to thrombosis, bleeding, and/or transformation to leukaemia. Chronic myelogenous leukaemia (CML) is characterised by increasing granulocytic cell proliferation with no loss of differentiation, leading to an increased number of granulocytes and their immature progenitors, with occasional blast cells on peripheral blood film. Polycythaemia Vera (PV) is a disorder of stem cells that presents a total hyperplasia, malignant, and cancerous marrow. Its most prominent feature is an increased absolute red blood cell mass due to uncontrolled red blood cell production, followed by increased myeloid and megakaryocytic production due to an abnormal clone of the haematopoietic stem cells with increased sensitivity to growth factors. Essential thrombocythemia (ET) is defined by a persistent increase in platelet count with a proclivity for thrombosis and haemorrhage. Expansion of megakaryocytes in the cell lineage leads to high platelet count, and the condition is thought to be clonal. Primary myelofibrosis (PMF) results in aberrant megakaryocyte development. Extramedullary haematopoiesis and reactive connective tissues are found in fully mature bone marrow (BM). PMF is linked to uncontrolled megakaryopoiesis as well as atypical, fibrosis, and hypercellularity. Haematological and morphological abnormalities in combinations with mutations (BCR-ABL, CARL, JAK2 or MPL) represent major diagnostic criteria for MPD. The WHO criteria for tumours of the hemopoietic and lymphoid tissues was revised in 2016. Prognostic models rely on clinical and haematological data, but new models with genetic information are being created for clinical trial environments. Management of most patients with MPDs involves treatment or monitoring symptoms associated with presenting disease and/or preventing other events such as thrombosis. Treatment modalities include symptomatic treatments, surgery, therapeutic radiation, therapeutic phlebotomy, therapeutic apheresis, cytoreductive therapy and haematopoietic stem cells transplantations.