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Hairy cell leukaemia

What is hairy cell leukaemia?

Hairy cell leukaemia (HCL) is a rare type of chronic leukaemia of the lymphoid system, in which abnormal B-lymphocytes accumulate in the bone marrow, liver and spleen. Under the microscope, these cells are seen to have tiny hair-like projections on their surface, hence their name “hairy cell”. B lymphocytes (also known as B-cells) are specialised white blood cells. Under normal conditions they produce immunoglobulins (also called antibodies) that help protect our bodies against infection and disease. In people with hairy cell leukaemia, lymphocytes undergo a malignant (cancerous) change and become leukaemic cells.

HCL is one of the lymphoproliferative disorders of which the most common is chronic lymphocytic leukaemia (CLL). HCL is classified as a chronic leukaemia meaning it develops slowly, often over many years.

Hairy cell leukaemia: the basics

How common is hairy cell leukaemia?

HCL is a rare form of leukaemia and accounts for only 2% of all leukaemias diagnosed.

Who gets hairy cell leukaemia?

HCL is more common in men than women and usually occurs in middle age (the median age of onset is 50). It does not occur in children and is very rare in adolescents.

What causes hairy cell leukaemia?

The causes of HCL remain unknown but it is thought to result from damage to one or more of the genes that normally controls blood cell development. We do know that it is not contagious or inherited or passed down through our genes.

What are the symptoms of hairy cell leukaemia?

Because HCL develops slowly many people don’t have any symptoms, particularly in the early stages. The disease is usually picked up during a routine blood test.

Other people may go to see their GP because they have some troubling symptoms of their disease. Symptoms arise from the increasing number of abnormal blood cells in the bone marrow and blood, and the decreasing number of normal blood cells. Possible symptoms may include:

  • anaemia, due to a lack of red cells causing persistent tiredness, dizziness, paleness, or shortness of breath when physically active
  • frequent or repeated infections and slow healing, due to a lack of normal white blood cells
  • pain or discomfort under the ribs on the left side, due to an enlarged spleen
  • painless swelling of the lymph nodes (glands) in your neck, under your arms or in your groin. This is usually a result of lymphocytes accumulating in these tissues.

Some of the symptoms described above may also be seen in other illnesses, including viral infections. So, most people with these symptoms don’t have leukaemia. However, it is important to see your doctor if you have any unusual symptoms, or symptoms that persist much longer than expected so that you can be examined investigated properly.

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Last updated on May 22nd, 2024

Developed by the Leukaemia Foundation in consultation with people living with a blood cancer, Leukaemia Foundation support staff, haematology nursing staff and/or Australian clinical haematologists. This content is provided for information purposes only and we urge you to always seek advice from a registered health care professional for diagnosis, treatment and answers to your medical questions, including the suitability of a particular therapy, service, product or treatment in your circumstances. The Leukaemia Foundation shall not bear any liability for any person relying on the materials contained on this website.