Rapid production of bone marrow constituents.

A group of disorders characterized by abnormal proliferation by one or more types of marrow cells. Four disorders are generally included as myeloproliferative disorders. These are poly cythemia vera (PV), myelofibrosis, chronic myelomonocytic leukemia (CMML) and primary thrombocythemia. Most commonly seen in people over 50 years of age. (Read about " Myelodysplastic Syndromes/Myeloproliferative Disorders")