Hairy cell leukemia (HCL) is a rare form of cancer. It involves white blood cells called B lymphocytes. White blood cells protect the body from infections and cancers. HCL gets its name from the tiny hair-like projections that protrude from the surface of these cancer cells. Illness results from the accumulation of these cancer cells in the bone marrow and spleen.

Cancer occurs when cells in the body become abnormal. They divide without control or order. Leukemia is cancer of the white blood cells and their parent cells. Leukemia cells do not function normally. They cannot do what normal blood cells do. In this case they can not fight infections. This means that the person is more likely to become infected with viruses or bacteria.

White Blood Cells

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The exact cause of HCL is unknown.

Risk Factors

Specific risk factors for HCL are unknown. The disease tends to occur more often in men. It also occurs more often in people over the age of 50.


HCL tends to develop slowly over a number of years. It often causes no symptoms at first. The cancerous cells eventually overgrow the bone marrow. This forces out other normal components, like red blood cells and platelets. Low red blood cell levels can cause anemia]]> . Low platelet levels can cause excess bleeding.

Symptoms may include:

  • Weakness and fatigue (due to anemia)
  • Enlarged spleen
  • Enlarged liver
  • Recurrent infections, often with fevers (due to low white cell count)
  • Ease in bruising and bleeding (due to low platelet count)
  • Night sweats
  • Swollen lymph nodes (rare)



The doctor will ask about your symptoms and medical history. A physical exam will be done. Tests may include:

  • Blood tests
  • Bone marrow biopsy]]> —removal of a sample of bone marrow tissue to test for cancer cells
  • ]]>CT scan]]> —a type of x-ray that uses a computer to make pictures of the spleen and the liver



HCL is a slow-growing cancer. It does not require aggressive treatment early on. As HCL progresses, treatment may include:


HCL can cause the spleen to enlarge. In this case, the spleen may be surgically removed. This is called a splenectomy]]> .


]]>Chemotherapy]]> is the use of drugs to kill cancer cells. It may be given in many forms. This includes pill, injection, and via a catheter. The drugs enter the bloodstream and travel through the body. While this will focus on cancer cells, some healthy cells are also killed.

Several new drugs show promise in the treatment of HCL. Initial chemotherapy is becoming more common as new drugs are found that work well in managing the disease. For resistant disease, there are some promising drugs that specifically target the leukemia cell such as:


Drugs are used to help boost the immune system to better fight and destroy cancer cells. It is also called biotherapy. Drugs like interleukin-2 and interferon may be used.

]]>Bone Marrow Transplant]]>

In this procedure, a patient's bone marrow is destroyed with high doses of chemotherapy and/or radiation. The bone marrow is then replaced with healthy bone marrow from another person (the donor). The donor's tissue needs to closely match the tissue of the patient.

Treatment of Symptoms

HCL patients with anemia often receive ]]>blood transfusions]]> . Those with recurrent infections may receive antibiotics and/or other drugs to fight the infections.


There are no guidelines for preventing HCL.