Overt Primary Myelofibrosis

**Semantic type:** Neoplastic Process

**Definition:** 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.

**Synonyms:** - Chronic Idiopathic Myelofibrosis, Fibrotic Stage - Primary Myelofibrosis, Fibrotic Stage - Primary Myelofibrosis, Overt Fibrotic Stage