Myelofibrosis is a disorder of the bone marrow in which the marrow is replaced by scar (fibrous) tissue. As bone marrow is the “factory” for normal blood cell production, scarring of marrow limits the ability of the body to make a sufficient number of blood cells to maintain healthy tissue. As a result, individuals with myelofibrosis may suffer from anemia or bleeding problems and are at a higher risk for infection. The liver and spleen often try to make some of these blood cells in response to an inadequate supply, causing these organs to swell – a condition called extramedullary (outside the bone marrow) hematopoiesis (blood cell production).
The cause of myelofibrosis is unknown and there are no known risk factors. The disorder usually develops slowly in people over age 50. Diseases such as leukemia and lymphoma may also cause bone marrow scarring, a condition called “secondary” myelofibrosis.
Symptoms include:
- Abdominal fullness related to an enlarged spleen
- Shortness of breath with exercise
- Bone pain
- Weakness or fatigue
- Unusually pale skin (pallor)
- Easy bruising or bleeding
There is no specific treatment for myelofibrosis – treatment depends on symptoms and severity of low blood counts. As scarring progresses, bone marrow failure with severe anemia results. Low platelet count leads to easy bleeding and spleen swelling. Although some people with myelofibrosis may survive for decades, the average survival for those with a diagnosis of primary myelofibrosis is about 5 years.