Pulmonary extra-medullary hematopoiesis and pulmonary hypertension from underlying polycythemia vera: a case series.

Myeloproliferative neoplasia (MPN)-associated pulmonary hypertension (PH) is included in group five of the most recent clinical classification of PH. The MPNs are a heterogeneous group of disorders that includes disorders with primary expression of a myeloid phenotype and disorders characterized by expression of the Janus Kinase 2 (JAK2) mutation, . The latter includes essential thrombocytosis, polycythemia vera, and idiopathic myelofibrosis. Pulmonary extra-medullary hematopoiesis (EMH) refers to the presence of hematopoietic precursor cells in the lung. It is a rare complication associated with myelofibrosis. Here we present a case series highlighting the clinical-pathological-radiological features of pulmonary EMH and PH from underlying polycythemia vera.