What Is Hairy Cell Leukemia?

Hairy cell leukemia (HCL) is a rare type of blood and bone marrow cancer that affects your B lymphocytes, which are white blood cells that make antibodies to fight infections. If you have HCL, your body produces a surplus of abnormal B lymphocytes that don’t function properly. These abnormal cells can take up the space of healthy B lymphocytes, which can weaken your immune system and make you susceptible to infections.

While the production of abnormal B lymphocytes is the hallmark of this disease, your body’s increased production of these abnormal cells can also cause a decrease in red blood cells and platelets. HCL gets its name because the abnormal white blood cells look hairy under a microscope. Rare cases of hairy cell leukemia affect T lymphocytes, which are cells that help B lymphocytes fight infection.

While the exact cause of HCL is unknown, some research shows a relationship between this type of cancer and exposure to the herbicide Agent Orange, which was used to destroy crops and jungle canopy during the Vietnam War. If you’re a veteran who has HCL and were exposed to Agent Orange during the Vietnam War, you may qualify for disability and healthcare benefits from the United States Department of Veterans Affairs.

Common symptoms of HCL include:

  • persistently feeling tired
  • weakness
  • weight loss for no reason
  • shortness of breath
  • excessive sweating, often at night
  • swollen lymph nodes
  • frequent infections and fevers
  • small red spots on the skin
  • an enlarged liver or spleen
  • easy bruising and bleeding
  • bone pain, especially under the ribs

HCL progresses slowly, and in its early stages, you may experience few or no symptoms at all.

If you have HCL, it is important to keep an eye out for symptoms that the cancer is progressing. Call your doctor if you generally don’t feel well or if you have any of the following:

  • a lot of bleeding
  • an infection
  • a persistent fever
  • a persistent cough

These may suggest that your white blood cell count is low. Proper care and timely treatment are crucial for your health.

This type of cancer affects more men than women, and most HCL diagnoses are made in people over 50 years of age.

Your doctor may suspect HCL based on your symptoms or if signs of the disease are present during a physical exam. Tests your doctor may perform to reach a diagnosis include the following:

  • A CT scan takes detailed images of your body and allows your doctor to view certain organs, such as the spleen or liver, which can be swollen if you have HCL.
  • A complete blood count is a measure of the amount of white and red blood cells and platelets in your blood.
  • A peripheral blood smear is a test in which your blood is viewed under a microscope to look for hairy cells.
  • If you have a bone marrow biopsy, your doctor will remove a small sample of your bone marrow using a hollow needle. The sample will be viewed under a microscope for signs of cancer.
  • A sample of your blood cells or bone marrow may be examined under a microscope for certain markers, such as protein patterns, that are found on the surface of HCL cells. This is called immunophenotyping.

Treatment will vary depending on the number of hairy cells and healthy cells in your blood and bone marrow, and whether you exhibit certain symptoms, such as a swollen or infected spleen. While some treatments may relieve and manage symptoms, none are known to cure it completely. You may need treatment if your normal blood cell counts are low, your spleen is swollen, or if you have an infection.

Common treatments include:

  • blood transfusions to increase blood count
  • chemotherapy treatments to kill abnormal cells
  • surgery to remove a swollen spleen
  • antibiotics to cure infection

If your HCL isn’t progressing and if you don’t have symptoms, your condition should be monitored but it may not require immediate treatment.

Treatment and recovery will depend on whether there’s a continuous increase in the number of hairy cells and the rate at which these cells develop. Most cases of HCL respond well to treatment and usually result in long-term remission, which occurs when the cancer has stopped progressing and your symptoms have gone away. If your symptoms return and the cancer begins to progress again, you may need to go through treatment again to put the cancer back into remission.