This condition causes the body to make too many progenitor cells, replacing marrow with fibrous or scar tissue. This prevents healthy blood-producing cells from growing normally and results in anemia, a low platelet count (cells involved in the clotting of the blood), and a tendency to develop infections.


  • A sense of abdominal fullness caused by enlargement of the spleen
  • Bone pain
  • Bruising and easy bleeding due to declining platelets
  • Fatigue
  • Increased susceptibility to infection
  • Pallor and shortness of breath related to anemia
  • Hyperuricemia (a high level of uric acid in the blood) and gout


  • Physical exam. A physician will examine the patient’s body, looking for any swelling in the lymph nodes, spleen, or abdomen and will then check vital signs, such as pulse and blood pressure.
  • Blood tests. A complete blood count (CBC) will show if there are very low levels of red blood cells. In patients with myelofibrosis, white blood cell levels and platelet counts may be higher or lower than normal. Immature or “younger” blood cells that are normally only seen in the bone marrow can be seen in the blood of patients with myelofibrosis.
  • Imaging tests. Imaging tests, such as X-rays and magnetic resonance imaging (MRI), may be used to gather more information about your myelofibrosis.
  • Bone marrow biopsy. A physician inserts a needle into the patient’s bone marrow at the hip to withdraw a sample of the bone marrow. This is examined under a microscope to determine the number and type of blood cells the body is producing.
  • Genetic testing. A sample of blood or bone marrow may be taken then analyzed in a laboratory to look for gene mutations associated with myelofibrosis. More than 90% of patients will have a mutation in one of three genes: calretuculin (CALR), MPL, or JAK2.

Risk Factors

While the cause of this condition is unknown, there are several acknowledged risk factors. These include:

• Age. Myelofibrosis can be diagnosed at any age but is most often found in patients who are in their 50s and 60s.
• Another blood cell disorder. A small percentage of patients develop myelofibrosis as a complication of essential thrombocythemia or polycythemia vera.
• Industrial chemicals. Exposure to toluene and benzene have been linked to myelofibrosis.
• High levels of radiation. Survivors of atomic bomb attacks and some patients who received a radioactive contrast dye called thorotrast, used from the 1920s to the 1950s, have contracted this disease.


This condition can be alleviated with transfusions to increase the number of red blood cells.

Ruxolitinib (Jakafi) can target the JAK2 protein and reduce spleen size, improve symptoms like itching or fatigue, and reduce the white blood cell count. It has been shown to improve survival.

Occasionally, surgery can be used in patients with very enlarged spleens.

For some patients, a bone marrow transplantation can provide a cure.

Myelofibrosis is a disease that is being approached with many new treatments at Columbia Cancer. 

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