Hairy Cell Leukemia

What is Hairy Cell Leukemia?

Hairy cell leukemia is a rare, slowly progressing blood cancer that begins in the bone marrow and usually occurs during or after middle age. Bone marrow is the spongy tissue found inside your bones. Bone marrow contains cells that produce white blood cells, red blood cells and platelets. White blood cells help fight infection. Red blood cells carry oxygen and nutrients and platelets enable the blood to clot.

Hairy cell leukemia develops when the DNA (genetic material) of a developing B lymphocyte (a type of white blood cell) becomes damaged, or mutated. The damaged blood cell looks “hairy” under a microscope. As that damaged cell multiplies, it passes on the mutation. These mutated cells no longer do the job of the healthy B lymphocyte, nor do they follow a normal pattern of cell life and death. Eventually, the mutated B lymphocytes begin to outnumber healthy white cells, red cells and platelets.

Baptist Health is known for advanced, superior care for patients with cancer and the diagnosis, treatment and management of hairy cell leukemia. Our specialist hematologist/oncologist and oncology certified nurses provide advanced cancer care in our facilities, which are accredited by the Commission on Cancer. Plus, our infusion centers make outpatient cancer care as convenient as possible.

You will appreciate timely appointments and a professional, friendly atmosphere where we take time to listen to your concerns. At Baptist Health, you have access to the region’s most comprehensive, multidisciplinary team of specialists and innovative therapies, including many available only through specialized clinical trials. In every way, we work to demonstrate the utmost in excellent care to those who trust us with their health.

Signs and Symptoms

The signs and symptoms of hairy cell leukemia can be subtle and sometimes seem like symptoms for another condition. These symptoms may include:

  • Pain or fullness below the ribs on the left side
  • Feeling run-down or tired
  • Easy bruising and bleeding
  • Recurring infections
  • Unexplained weight loss
  • Weakness
  • Shortness of breath
  • Excessive sweating, often at night
  • Swollen lymph nodes
  • Small red spots on the skin
  • An enlarged liver or spleen


To determine if someone has hairy cell leukemia, we ask about medical history and do a physical exam, particularly looking for an enlarged spleen or lymph nodes. We also use advanced diagnostic procedures and technology to effectively diagnose, inform treatment and carefully monitor the condition. Diagnostic procedures can include:

Physical tests: Doctors may check your spleen and liver to check if it is enlarged. They will also check to see if your lymph nodes are swollen.

Blood test: Blood tests check for low levels of all three types of blood cells, and specifically for the hairy cells.

Bone marrow test: During this test, a local anesthetic is used to numb the area where the sample of bone marrow will be taken, typically on the hip. A small incision is made and a thin, hollow needle goes into the bone to collect a small portion of marrow to examine for hairy cells.

CT scan: X-rays and computers are used to create detailed images of the spleen and lymph nodes to look for enlargement.


When doctors search for hairy cell leukemia causes, they focus on the three types of cells in your blood– red blood cells, white blood cells, and platelets. Each type serves a specific purpose. Red blood cells infuse your tissues with oxygen. White blood cells defend your body from infections. Platelets congeal into blood clots to prevent bleeding.

All three types begin as stem cells in bone marrow. A mutation in your genes can cause your body to produce more white blood cells than red blood cells or platelets. These excess white blood cells, known as cancerous B lymphocytes or leukemia cells, do not protect against infection like standard white blood cells. Hairy cell leukemia is a rare type of leukemia. For most people, there is no obvious reason for developing the disease.

Risk Factors

Risk factors that can contribute to hairy cell leukemia include:

Age: Hairy cell leukemia is most often diagnosed in adults.

Gender: Hairy cell leukemia is more often diagnosed in men than in women.

Radiation exposure: Certain radiation therapies can increase the risk of hairy cell leukemia.

Exposure to certain chemicals: Over exposure to industrial and agricultural chemicals may increase the risk of hairy cell leukemia.

Ethnicity: Hairy cell leukemia affects men of Ashkenazi Jewish ancestry more frequently than men of other ethnic groups. 


Risk factors cannot be controlled. Hairy cell leukemia is not affected by lifestyle habits nor can it be caught from someone.


While hairy cell leukemia is a rare condition, it is one of the most successfully treated cancers. Regular follow-up is important.

Treatment and Recovery

Not all people require treatments immediately after diagnosis. The goal of treatment of hairy cell leukemia is to treat symptoms and eliminate as many of the mutated blood cells that cause cancer cells, and replace them with healthy cells. It is generally not possible to eliminate all of those cells, but treatment can result in long-term remission of the disease. Remission is when the cancer is less active or there are no signs of cancer.

Treatment depends upon how advanced the cancer is, and can include:

  • Watch and wait: If the cancer cells are growing slowly, a doctor may monitor symptoms before starting a treatment plan.
  • Chemotherapy uses special drugs designed to kill cancer cells. Chemotherapy for hairy cell leukemia can be given as an infusion or injection.
  • Immunotherapy is a type of cancer treatment designed to help the body boost its natural defenses to fight the cancer.
  • Surgery is a treatment if the condition causes the spleen to rupture or if it is enlarged and painful. 

Your doctor will prescribe treatment based on several factors, such as the progression of your cancer and your specific symptoms.

Additional factors include:

  • The levels of healthy cells vs. hairy leukemia cells in your blood.
  • The size of your spleen.
  • Any infections you might develop.
  • If you experience fevers or sweats.
  • Any unexplained weight loss.
  • Recurring HCL after treatment.


Because hairy cell leukemia means fewer healthy red blood cells, white blood cells and platelets, there are a number of complications that can result. These include:

Anemia: When healthy red blood cells are crowded out by the cancer cells, it can cause fatigue and shortness of breath.

Neutropenia: Because the white blood cells are not healthy, the immune system can’t effectively fight infections.

Thrombocytopenia: Because the platelets are crowded out by the cancer cells, it causes bruising and bleeding.

Enlarged spleen: The hairy cells may invade the spleen and cause discomfort or rupture.

Liver infection: The hairy cells may invade the liver and cause discomfort or abnormal liver function.

Lymph node enlargement: The hairy cells and invade the lymph nodes and cause neck and abdomen pain.

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