hairy cell leukemia
Also written as: HCL — hairy cell leukemia
A rare B-cell malignancy characterized by lymphocytes with distinctive cytoplasmic projections resembling hairs.
Full Definition
Hairy cell leukemia is an uncommon B-cell chronic lymphoproliferative disorder characterized by the accumulation of abnormal B lymphocytes with distinctive cytoplasmic projections that give them a 'hairy' appearance on microscopy. The disease predominantly affects middle-aged men and typically presents with pancytopenia, splenomegaly, and bone marrow infiltration. The malignant cells show characteristic immunophenotypic features and are positive for tartrate-resistant acid phosphatase (TRAP). Most cases are associated with the BRAF V600E mutation. The disease has an indolent course, and treatment with purine analogs such as cladribine typically achieves durable remissions.
Usage
Usage note: The descriptive term 'hairy' refers to the characteristic cytoplasmic projections, not patient appearance.
In Context
- "The peripheral blood smear showed lymphocytes with hairy projections consistent with hairy cell leukemia." — laboratory report
- "TRAP staining was positive, supporting the diagnosis of hairy cell leukemia." — pathology report