Overview
Hairy cell leukemia variant (HCL-V) is a rare type of blood cancer that affects white blood cells called B-lymphocytes. It is considered a separate disease from classic hairy cell leukemia, even though the names sound similar. In HCL-V, abnormal white blood cells build up in the blood, bone marrow, and spleen. These abnormal cells can crowd out healthy blood cells, leading to low blood counts, an enlarged spleen, and increased risk of infections. Unlike classic hairy cell leukemia, the variant form tends to have a higher white blood cell count and the abnormal cells look slightly different under the microscope — they have a prominent nucleolus (a visible dot inside the cell nucleus). Patients often notice fatigue, frequent infections, easy bruising or bleeding, and a feeling of fullness in the abdomen due to an enlarged spleen. HCL-V is generally more difficult to treat than classic hairy cell leukemia. Standard treatments for classic HCL, such as cladribine and pentostatin, are often less effective in the variant form. Treatment options may include splenectomy (surgical removal of the spleen), rituximab (a targeted antibody therapy), or combination chemotherapy regimens. Newer targeted therapies are being studied in clinical trials. Because HCL-V is rare and behaves differently from classic HCL, it is important to get an accurate diagnosis so the right treatment plan can be developed. The disease primarily affects older adults and tends to follow a more aggressive course than classic hairy cell leukemia.
Also known as:
Key symptoms:
Extreme tiredness and fatigueEnlarged spleen causing fullness or pain in the upper left abdomenFrequent or severe infectionsEasy bruising or unusual bleedingLow red blood cell count (anemia)Low platelet countHigh white blood cell count with abnormal cellsUnexplained weight lossNight sweatsWeaknessPale skinShortness of breath with activityFeeling of heaviness in the belly
Sporadic
Usually appears on its own, not inherited from a parent
Adult
Begins in adulthood (age 18 or older)
Treatments
No FDA-approved treatments are currently listed for Hairy cell leukemia variant.
View clinical trials →Clinical Trials
View all trials with filters →No actively recruiting trials found for Hairy cell leukemia variant at this time.
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Treatment Centers
8 centersBaylor College of Medicine Rare Disease Center ↗
Baylor College of Medicine
📍 Houston, TX
🏥 NORDStanford Medicine Rare Disease Center ↗
Stanford Medicine
📍 Stanford, CA
🔬 UDNNIH Clinical Center Undiagnosed Diseases Program ↗
National Institutes of Health
📍 Bethesda, MD
🔬 UDNUCLA UDN Clinical Site ↗
UCLA Health
📍 Los Angeles, CA
🔬 UDNBaylor College of Medicine UDN Clinical Site ↗
Baylor College of Medicine
📍 Houston, TX
🔬 UDNHarvard/MGH UDN Clinical Site ↗
Massachusetts General Hospital
📍 Boston, MA
🏥 NORDMayo Clinic Center for Individualized Medicine ↗
Mayo Clinic
📍 Rochester, MN
👤 Mayo Clinic Center for Individualized Medicine
🏥 NORDUCLA Rare Disease Day Program ↗
UCLA Health
📍 Los Angeles, CA
Travel Grants
No travel grants are currently matched to Hairy cell leukemia variant.
Community
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Caregiver Resources
NORD Caregiver Resources
Support, advocacy, and financial assistance for caregivers of rare disease patients.
Mental Health Support
Rare disease caregiving can be isolating. Connect with counseling and peer support.
Family & Caregiver Grants
Financial assistance programs specifically for caregivers of rare disease patients.
Social Security Disability
Learn how rare disease patients may qualify for SSDI/SSI benefits.
Questions for your doctor
Bring these to your next appointment
- Q1.How do you know this is hairy cell leukemia variant and not classic hairy cell leukemia?,What molecular or genetic testing has been done on my cancer cells, and do I have a MAP2K1 mutation?,What treatment do you recommend as a first approach, and what are the expected response rates for HCL-V specifically?,Are there any clinical trials available for hairy cell leukemia variant that I might be eligible for?,How often will I need blood tests and follow-up visits to monitor my disease?,What signs or symptoms should prompt me to seek emergency care?,Should I be referred to a center with specific expertise in rare leukemias?
Common questions about Hairy cell leukemia variant
What is Hairy cell leukemia variant?
Hairy cell leukemia variant (HCL-V) is a rare type of blood cancer that affects white blood cells called B-lymphocytes. It is considered a separate disease from classic hairy cell leukemia, even though the names sound similar. In HCL-V, abnormal white blood cells build up in the blood, bone marrow, and spleen. These abnormal cells can crowd out healthy blood cells, leading to low blood counts, an enlarged spleen, and increased risk of infections. Unlike classic hairy cell leukemia, the variant form tends to have a higher white blood cell count and the abnormal cells look slightly different und
How is Hairy cell leukemia variant inherited?
Hairy cell leukemia variant follows a sporadic inheritance pattern. Genetic counseling can help families understand recurrence risk and testing options.
At what age does Hairy cell leukemia variant typically begin?
Typical onset of Hairy cell leukemia variant is adult. Age of onset can vary across affected individuals.
Which specialists treat Hairy cell leukemia variant?
21 specialists and care centers treating Hairy cell leukemia variant are listed on UniteRare, sourced from ClinicalTrials.gov principal investigators, published research, and the NPPES NPI registry.