Hairy cell leukemia is a cancer of the blood and bone marrow. This rare type of leukemia gets worse slowly or does not get worse at all. The disease is called hairy cell leukemia because the leukemia cells look “hairy” when viewed under a microscope.

In hairy cell leukemia, too many blood stem cells become lymphocytes. These lymphocytes are abnormal and do not become healthy white blood cells. They are also called leukemia cells. The leukemia cells can build up in the blood and bone marrow so there is less room for healthy white blood cells, red blood cells, and platelets. This may cause infection, anemia, and easy bleeding. Some of the leukemia cells may collect in the spleen and cause it to swell.

Signs & Symptoms

These and other signs and symptoms may be caused by hairy cell leukemia or by other conditions. Check with your doctor if you have any of the following:

  • Weakness or feeling tired
  • Fever or frequent infections
  • Easy bruising or bleeding
  • Shortness of breath
  • Weight loss for no known reason
  • Pain or a feeling of fullness below the ribs due to enlargement of the spleen
  • Painless lumps in the neck, underarm, stomach, or groin


Your OHC doctor will help you determine the best care plan for you. Standard treatment includes:

  • Watchful waiting is closely monitoring a patient’s condition, without giving any treatment until signs or symptoms appear or change.
  • Chemotherapy is a cancer treatment that uses drugs to stop the growth of cancer cells, either by killing the cells or by stopping them from dividing.
  • Biologic therapy is a cancer treatment that uses the patient’s immune system to fight cancer. Substances made by the body or made in a laboratory are used to boost, direct, or restore the body’s natural defenses against cancer. This type of cancer treatment is also called biotherapy or immunotherapy. Interferon alfa is a biologic agent commonly used to treat hairy cell leukemia.
  • Splenectomy is a surgical procedure to remove the spleen.
  • Targeted therapy is a treatment that uses drugs or other substances to identify and attack specific cancer cells without harming normal cells. Monoclonal antibody therapy is a type of targeted therapy used to treat hairy cell leukemia.