Hairy cell leukemia (HCL) is an uncommon, indolent, mature B-cell neoplasm. It is characterized by symptoms of fatigue, a markedly enlarged spleen, pancytopenia, and a distinctive histologic appearance on peripheral blood smear and bone marrow biopsy.
HCL is not curable. However, it is highly responsive to therapy; median relapse-free survival of a decade or more has been reported.
In asymptomatic patients with well-preserved blood counts, immediate treatment is not required.
In symptomatic patients or those with worsening blood counts, treatment with purine analogs is recommended.
Supportive care with antibiotics, anti-infective prophylaxis, granulocyte colony-stimulating factor, irradiated blood products, and nonsteroidal anti-inflammatory drugs may be required as part of treatment.
HCL is an indolent mature B-cell neoplasm. It is considered to be a type of non-Hodgkin lymphoma. Seen under the microscope, the leukemic cells have delicate cytoplasmic projections resembling hair ("hairy cells"). The disease has a characteristic presentation of pancytopenia, splenomegaly, and hairy cells in the peripheral blood, bone marrow, and other hematopoietic organs.
History and exam
Key diagnostic factors
- abdominal fullness or discomfort
Other diagnostic factors
- weakness and fatigue
- unexplained weight loss
- bruising and bleeding
- pallor and petechiae
- recurrent infections
- superficial and deep lymphadenopathy
- neurologic findings
- associated systemic immunologic disorders
- middle age
- male sex
- white ancestry
- western hemisphere location
- environmental exposures
- genetic predisposition
- Epstein-Barr virus
- infectious mononucleosis
1st investigations to order
- peripheral blood smear
- bone marrow trephine biopsy and aspiration (morphology assessment)
Investigations to consider
- flow cytometry
- molecular analysis (for BRAF V600E mutation or IGHV4-34 rearrangement)
- CT of abdomen
symptomatic: without splenic rupture or massive splenomegaly or marked thrombocytopenia precluding chemotherapy
symptomatic: with splenic rupture or massive splenomegaly or marked thrombocytopenia precluding chemotherapy
asymptomatic disease or minimal residual disease after treatment
- Chronic lymphocytic leukemia (CLL)
- Mantle cell lymphoma
- Prolymphocytic leukemia
- NCCN clinical practice guidelines in oncology: hairy cell leukemia
- Guideline for diagnosis and management of hairy cell leukaemia (HCL) and hairy cell variant (HCL-V)
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