Hairy Cell Leukaemia

Hairy cell leukaemia (HCL) is a rare type of chronic leukaemia of the lymphoid system.

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What is hairy cell leukaemia?

Hairy cell leukaemia (HCL) is a rare type of chronic leukaemia of the lymphoid system. It is called a ‘leukaemia’ because it can be found in the blood and bone marrow (the spongy tissue in the centre of bones where blood cells are made).

 The abnormal B-lymphocytes accumulate in the bone marrow, liver, and spleen. HCL is classified as a chronic leukaemia meaning it develops slowly, often over many years.

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

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.

Under the microscope, these cells are seen to have tiny hair-like projections on their surface, hence their name “hairy cell”.

Who is affected by Hairy cell leukaemia (HCL)?

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 rare in adolescents.

What are the symptoms of hairy cell leukaemia?

Because HCL develops slowly many people do not have any symptoms. 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. Possible symptoms may include:

  • Persistent tiredness
  • Dizziness
  • Paleness 
  • Shortness of breath when physically active
  • Frequent or repeated infections and slow healing
  • Pain or discomfort under the ribs on the left side
  • Painless swelling of the lymph nodes (glands) in your neck, under your arms or in your groin. 

Some of the symptoms described above may also be seen in other illnesses. Most people with these symptoms do not have leukaemia. It is important to see your doctor if you have any unusual symptoms, or symptoms that persist much longer than expected.

Diagnosis of Hairy Cell Leukaemia (HCL)

When you see your doctor about any of your symptoms, they will probably take:

  • A full medical history, asking questions about your general health, any illness or surgery you have had previously. 
  • They will give you a full physical examination 
  • Examine samples of your blood and bone marrow.

Full blood count

The first step in the diagnosis is a simple blood test called a full blood count (FBC). This involves taking a sample of blood from a vein in your arm being sent to the laboratory for investigation. Most people with HCL have a low red cell and platelet count. Many of the white blood cells may be abnormal leukaemic blast cells and the presence of these blast cells suggests you have HCL.

Bone marrow examination

If the results of your blood tests suggest that you might have HCL, a bone marrow biopsy may be required to help confirm the diagnosis. A bone marrow biopsy involves taking a sample of bone marrow (usually from the back of the hip bone) and sending it to the laboratory for examination under the microscope. The sample of bone marrow is examined in the laboratory to determine the number and type of cells present and the amount of haematopoiesis (blood forming) activity taking place there.

Further testing

Once a diagnosis of HCL is made, blood and bone marrow cells are examined further using special laboratory tests. These include cytogenetic, immunophenotyping and immunoglobulin (antibody) level tests. These tests provide more information about the exact type of disease you have, the likely course of your disease and the best way to treat it.

Waiting for results can be a difficult time.  It may help to talk to your family, friends, or a specialist nurse.

For more info see
Diagnosis of lymphoma & CLL


There is no widely agreed staging system for hairy cell leukaemia.

Doctors use your test results to check how far your leukaemia has developed. This is called staging. Most types of cancer have a numbered stage, from 1 to 4, but this is not really used for hairy cell leukaemia.

Prognosis/Outlook of Hairy cell leukaemia (HCL)

The outlook for hairy cell leukaemia is usually particularly good. Most people with hairy cell leukaemia have a normal life expectancy. Treatment usually puts the disease into remission (no evidence of hairy cell leukaemia in your tests) and remissions often last many years. Hairy cell leukaemia can relapse (come back) but nearly all people who relapse are treated successfully again.

Treatment for Hairy cell leukaemia (HCL)

Once all the results from the biopsy and the staging scans have been completed, the doctor will review these to decide the best possible treatment for you.   At some cancer centres, the doctor will also meet with a team of specialists to discuss the best treatment for you. This is called a multidisciplinary team (MDT) meeting.  

Your doctors will take into consideration many factors about your lymphoma and general health to decide when and what treatment is required. This is based on:

  • The stage and grade of lymphoma 
  • Symptoms 
  • Previous treatment
  • Age, past medical history & general health
  • Current physical and mental wellbeing
  • Preferences

The standard treatments for Hairy cell leukaemia (HCL) may include:

  • Watch and wait 
  • Chemotherapy – Cladribine 
  • Targeted therapy – Rituximab or  Interferon 
  • Splenectomy 
  • Clinical trial participation

Common side effects of treatment

There are many different side effects of the treatment, that is individual for each treatment regimen.  The treating doctor and/or cancer nurse will explain these to the patient prior to starting treatment.  

For further information on some of the most and less common side effects, including ways to help self-manage these see the section on ‘common side-effects’.

Some of the most common side effects include:

  • Neutropenia (low type of white blood cell that helps to fight infection)
  • Thrombocytopenia (low platelets that help with clotting or bleeding)
  • Anaemia (low red cells that help provide oxygen to your body)
  • Nausea and vomiting
  • Bowel problems (constipation or diarrhea)
  • Fatigue (tiredness or lack of energy)

The medical team, doctor, cancer nurse or pharmacist, should provide information about the treatment, the common side effects, what symptoms to report and who to contact.  If not, please ask these questions when before leaving the cancer centre.

Follow-up care for Hairy cell leukaemia (HCL)

Once treatment has completed, there will be post treatment staging scans to review how well the treatment has worked and if a complete response (CR or no signs of lymphoma remains) or partial response (PR or there is still lymphoma present), but it has reduced in size.

Patients will need to be followed up by the doctor with regular follow-up appointments, usually every 3-6 months.  These appointments are important so that the medical team can check how well the patient is recovering from treatment.  The medical team will want to know how the patient is  feeling both physically and mentally, and to: 

  • Review the effectiveness of the treatment
  • Monitor any ongoing side effects from the treatment over time
  • Monitor for any late effects from treatment
  • Monitor signs of the lymphoma relapsing

Patients are likely to have a physical examination and blood tests for these appointments.  Apart from immediately after treatment to review how the treatment has worked, scans are not usually done unless there is a reason for them. For some patient’s appointments may become less frequent over time.

Treatment Under Investigation for Hairy cell leukaemia (HCL)

There are many treatments that are currently being tested in clinical trials around the world for patients with both newly diagnosed and relapsed lymphoma.  

Common drugs under investigation include:

  • Vemurafenib
  • Ibrutinib (Imbruvica)
  • Moxetumomab (Lumoxiti)

Late effects

Sometimes a side effect from treatment may continue or can develop months or years after treatment has completed.  This is called a late effect.  For more information, go to the ‘late effects’ section to learn more about some of the early and late effects that can occur after treatment for lymphoma. 

Finishing Treatment

Finishing treatment can be a challenging time for many people, as they readjust back into life after treatment.  Some people may not start to feel some of these challenges for weeks to months after cancer treatment has completed, as they start to reflect on their experience or do not feel that they are recovering as quickly as they should.  Some of the common concerns can be related to: 

  • Physical
  • Mental wellbeing
  • Emotional health
  • Relationships 
  • Work, study, and social activities

For further information, and ways to help you readjust after treatment for lymphoma, please visit the section ‘finishing treatment’.

For more info see
Finishing Treatment

Health and wellbeing

A healthy lifestyle, or some positive lifestyle changes after treatment can be a great help after the treatment has been finished.  Making small changes such as eating and increasing fitness can improve health and wellbeing and help the body to recover.  There are many self-care strategies that can help during the recovery phase. 

For more info see
Health & Wellbeing

Support and information

Learn more about your blood tests here – Lab tests online

Learn more about your treatments here – eviQ anticancer treatments – Lymphoma

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