label: Overt Primary Myelofibrosis
label_lc: overt primary myelofibrosis
description: "Primary myelofibrosis characterized by reticulin or collagen fibrosis in the bone marrow. The bone marrow is usually normocellular or hypocellular. Myeloblasts account for less than 10% of the bone marrow cells. Atypical megakaryocytes are present."