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  • Definition

    Myelofibrosis is a disorder in which bone marrow tissue develops in abnormal sites because the bone marrow itself undergoes fibrosis or scarring.

    Characteristic of the condition are anemia, splenomegaly (abnormal enlargement of the spleen), immature blood cells in the circulation, and hematopoiesis (formation and development of blood cells) occurring in the liver and spleen. Also called myeloid metaplasia and agnogenic myeloid metaplasia.

    Myeloid metaplasia may be secondary to carcinoma, leukemia, polycythemia vera, or tuberculosis.


    Myelofibrosis is characterized by the development of fibrous tissue, which replaces the bone marrow.

    Since bone marrow is important for making blood cells, myelofibrosis interferes with and reduces the production of blood cells. This causes anemia, and places an increased burden on the spleen, lymph nodes, and liver as these organs attempt to make more blood cells (extramedullary hematopoiesis). In turn, this causes the organs to become enlarged.

    Myelofibrosis is very serious, difficult to treat, and death is common within one year of diagnosis.


    The cause is unknown. This condition is rare in children but when it occurs, it progresses very rapidly.


    Myelofibrosis usually develops in adults over age 50 and is often insidious in onset. Patients most commonly present with fatigue related to their anemia or abdominal fullness related to splenomegaly.

    Uncommon presentations include bleeding and bone pain. On examination, splenomegaly is almost invariably present and is sometimes massive. The liver is enlarged in more than half of cases.

    Later in the course of the disease, progressive bone marrow failure takes place as the marrow becomes progressively more fibrotic. Anemia becomes severe, and red cell transfusion becomes necessary. Progressive thrombocytopenia (decrease in number of platelets in circulating blood) leads to bleeding. The spleen continues to enlarge in excess.

    Painful episodes of splenic infarction may occur. Late in the course of the disease, the patient becomes cachetic (in ill health, weak and emaciated) and may experience severe bone pain, especially in the lower legs. Hematopoiesis in the liver leads to portal hypertension with ascites, esophageal varices, and eventually liver failure.


    There is no specific treatment for this disorder. Anemic patients are supported with red blood cells in transfusion. Androgens such as oxymetholone or testosterone may help reduce the transfusion requirement but are poorly tolerated by women.

    Recombinant erythropoietin (epoetin alfa; Epogen) has been reported to be of value in a small number of cases. Splenectomy is not routinely performed, but is indicated for splenic enlargement that causes recurrent painful episodes, severe thrombocytopenia, or an unacceptably high red blood cell transfusion requirement.

    It is often hard to date the onset of myelofibrosis, but the median survival from time of diagnosis is approximately five years. End-stage myelofibrosis is a wasting illness characterized by general disability, liver failure, and bleeding from thrombocytopenia.


    Are there any tests that need to be done to diagnose the condition or the extent of involvement?

    How serious is the condition?

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    Will surgery be required? How is the surgery performed? What can be expected from the surgery?

    Are there any experimental studies on this disease?

    Is there a support group in the area?