Myelofibrosis is a disorder of the bone marrow, in which the marrow is replaced by scar (fibrous) tissue.
Idiopathic myelofibrosis; Myeloid metaplasia; Agnogenic myeloid metaplasia; Primary myelofibrosis; Secondary myelofibrosis
Causes, incidence, and risk factors
Bone marrow is the soft, fatty tissue inside your bones. Stem cells are immature cells in the bone marrow that give rise to all of your blood cells. Your blood is made of:
- Red blood cells (which carry oxygen to your tissues)
- White blood cells (which fight infection)
- Platelets (which help your blood clot)
Scarring of the bone marrow means the marrow is not able to make enough blood cells.
As a result, the liver and spleen try to make some of these blood cells. This causes these organs to swell, which is called extramedullary hematopoiesis.
The cause of myelofibrosis is unknown. There are no known risk factors. The disorder usually develops slowly in people over age 50.
Diseases such as