Classic hairy cell leukemia

Classic hairy cell leukemia (HCL) is a rare, slow-growing type of blood cancer that affects a type of white blood cell called B lymphocytes. The name comes from the way the cancer cells look under a microscope — they have tiny hair-like projections on their surface. HCL is sometimes called hairy cell leukemia classic type to distinguish it from a rarer variant form. The disease causes the bone marrow to fill up with abnormal cells, which crowds out healthy blood cells and leads to low counts of red blood cells, white blood cells, and platelets. Because of these low blood counts, people with HCL often feel very tired, get infections easily, and may bleed or bruise more than usual. The spleen — an organ in the upper left belly — often becomes enlarged, which can cause discomfort or a feeling of fullness. Many people are diagnosed after a routine blood test shows abnormal results, even before they feel very sick. The good news is that HCL responds very well to treatment. Most people achieve long-lasting remission — meaning the cancer goes away or becomes undetectable — with a single course of chemotherapy. The most commonly used treatments are drugs called cladribine and pentostatin. While HCL is not usually considered curable in the traditional sense, many patients live for decades with excellent quality of life after treatment.

Data sourced from FDA regulatory filings and ClinicalTrials.gov. Updated periodically.

Bring these to your next appointment

• Q1.Which treatment do you recommend for me, and why — cladribine or pentostatin?,How will we know if the treatment is working, and what does remission look like for my case?,What are the most common side effects of treatment, and how can I manage them?,How often will I need blood tests and check-ups after treatment?,What signs should I watch for that might mean the disease has come back?,Are there any clinical trials I should consider?,Are there any vaccines or medications I should avoid because of my weakened immune system?

Common questions about Classic hairy cell leukemia

Related conditions

Other rare diseases commonly researched alongside Classic hairy cell leukemia.

• Splenic diffuse red pulp small B-cell lymphoma→
• Splenic marginal zone lymphoma→