Primary myelofibrosis

Alternative names:

agnogenic myeloid metaplasia; idiopathic myelofibrosis; myelofibrosis; myeloid metaplasia

Definition:

A disorder of the bone marrow in which the marrow is replaced by fibrous (scar) tissue.

Causes, incidence, and risk factors:

In primary myelofibrosis, blood formation occurs in sites other than the bone marrow, such as the liver and spleen, causing enlargement of these organs. The cause is unknown. The disorder usually develops slowly in persons over 50 years old. It leads to progressive bone marrow failure with severe anemia. Low platelet count leads to easy bleeding, and spleen enlargement continues. The disease is progressive without a cure. The incidence is 2 out of 100,000 people.