Myelofibrosis is a disorder of the bone marrow in which the marrow is replaced by fibrous scar tissue.


Bone marrow is the soft, fatty tissue inside your bones. Stem cells are immature cells in the bone marrow that develop into all of your blood cells. Your blood is made of:

When the bone marrow is scarred, it cannot make enough blood cells. Anemia, bleeding problems, and a higher risk for infections may occur.

As a result, the liver and spleen try to make some of these blood cells. This causes these organs to swell.

The cause of myelofibrosis is unknown. There are no known risk factors. When it occurs, it often develops slowly in people over age 50.

Blood and bone marrow cancers such as myelodysplastic syndrome, leukemia, and lymphoma may also cause bone marrow scarring. This is called secondary myelofibrosis.


Symptoms may include any of the following:

Exams and Tests

The health care provider will perform a physical exam and ask about the symptoms.

Tests that may be done include:


Bone marrow or stem cell transplant may improve symptoms, and may cure the disease. This treatment is usually considered for younger people.

Other treatment may involve:

Outlook (Prognosis)

As the disease worsens, the bone marrow slowly stops working. Low platelet count leads to easy bleeding. Spleen swelling may get worse along with anemia.

Survival of people with primary myelofibrosis is about 5 years. But some people survive for decades.

Possible Complications

Complications may include:

When to Contact a Medical Professional

Make an appointment with your provider if you have symptoms of this disorder. Seek medical care right away for uncontrolled bleeding, shortness of breath, or jaundice (yellow skin and whites of the eyes) that gets worse.

Review Date: 5/20/2016
Reviewed By: Todd Gersten, MD, Hematology/Oncology, Florida Cancer Specialists & Research Institute, Wellington, FL. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.

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