Primary myelofibrosis

Definition:

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

Alternative Names:

Myelofibrosis; Idiopathic myelofibrosis; Myeloid metaplasia; Agnogenic myeloid metaplasia

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 in most cases. Risk factors are unknown.

Symptoms:

Fatigue
Abdominal fullness related to an enlarged spleen
Easy bleeding
Bone pain
Pallor
Shortness of breath on exertion
Bruising
Increased susceptibility to infection

Signs and tests:

Physical examination shows an enlarged spleen. Later in the disease, it may also show an enlarged liver.

A peripheral smear shows teardrop-shaped red blood cells.
The white blood cell count is variable.
The platelet count is variable.
Bone marrow biopsy may be performed to rule out other causes of the symptoms.
CBC shows a low red blood cell count.

Treatment:

There is no specific treatment for primary myelofibrosis. Blood transfusions are given to correct anemia. Recombinant erythropoietin or androgens may stimulate red blood cell production and may be beneficial. Splenectomy (removal of the spleen) may be indicated where splenic enlargement causes symptoms related to its size. Radiation and chemotherapy may also be used. Use of bone marrow transplantation in young patients appears to improve outcome.

Expectations (prognosis):

The median survival of people with primary myelofibrosis is about 5 years. However, many people survive for decades. End-stage disease is a wasting illness with debility.

Complications:

Liver failure
Acute myelogenous leukemia

Calling your health care provider:

Call for an appointment with your health care provider if symptoms of this disorder develop. Uncontrolled bleeding, shortness of breath, jaundice, and progressive confusion are symptoms that indicate a need for urgent or emergency care.

Prevention:

There is no known prevention.

Review Date: 10/10/2001
Reviewed By: Rebecca Elstrom, M.D., Division of Hematology-Oncology, University of Pennsylvania Medical Center, Philadelphia, PA. Review provided by VeriMed Healthcare Network.

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