Hairy cell leukemia

Abstract

The WHO categorizes hairy cell leukemia (HCL) as a mature B-cell neoplasm. HCL is characterized by lymphocytes with prominent cytoplasmic projections (hairy cells) infiltrating the bone marrow and spleen, leading to pancytopenia, bone marrow fibrosis, and splenic enlargement. Hairy cells have a unique immunophenotypic profile-CD11c+, CD20+, CD25+, and CD103+-that confirms its diagnosis. The course of HCL is usually chronic, but can often be progressive, and most patients require treatment at some point. The purine nucleoside analogues, pentostatin and cladribine, are highly active, but cladribine is the preferred first-line choice due to its efficacy, brief treatment duration, and favorable toxicity profile. Other therapeutic options include rituximab, interferon-alpha, vemurafenib, and splenectomy. With current therapy, an overall survival of 87% at 12 years has been reported.