Polycythemia vera is characterised by peripheral erythrocytosis. It is commonly caused by a point mutation in JAK2. Thrombocytosis and leukocytosis can also occur in addition to erythrocytosis. The classic presentation is an unexplained high haemoglobin with low MCV and low…

Chronic neutrophilic leukaemia is a rare aggressive myeloproliferative neoplasm that is characterised by persistent mature neutrophils, granulocyte hyperplasia, and hepatosplenomegaly. It is associated with mutations in Colony Stimulating Factor-3 (CSF-3) receptors.

Mastocytosis is characterised by mast cell proliferation and accumulation within various organs, most commonly the skin. It is associated with mutations in KIT (a transmembrane tyrosine kinase receptor for SCF)

Essential thrombocythaemia is characterised by an increase in the number of circulating platelets, due to the mutations JAK2, CARL, or MPL (90%), which cause sustained proliferation of megakaryocytes. Patients have a persistently elevated platelet count (>450,000/uL) and splenomegaly, and frequently…

Primary myelofibrosis is characterised by the replacement of bone marrow by fibrous tissue. There are abnormal proliferating megakaryocytes and granulocytes that produce cytokines that stimulate fibrosis. The typical presentation is a patient with anaemia, teardrop RBCs, leukoerythroblastosis, and hepatosplenomegaly. No…

Atypical chronic myeloid leukaemia is characterised by myelodysplasia and myeloproliferation at the outset. However, it does not meet the criteria for bcr-abl+ CML or other MPNs. It affects men more than women, and the median age of diagnosis is 70…