Hairy Cell Leukemia.

Hairy cell leukemia (HCL) is an indolent B-cell lymphoproliferative disease, characterized by splenomegaly and pancitopenia related to this. The lymphocytes present characteristic citoplasmatic projections and are positive for tartrate-resistant acid phosphatase (TRAP). Immunophenotyping is necessary to identify the co expression of CD103, CD25, CD11c associated with a typical B-cell clonally pattern and to make a differential diagnosis from other indolent malignancies. Despite the indolent clinical course, treatment is required to resolve symptoms related to splenomegaly and to reduce the incidence of severe infections that are the major complications and a common cause of death. In the past the treatment was only able to resolve the symptoms. In the revised literature, purine analog have been identified as the treatment of choice for this disease. Cladribrine (2-CdA) is able to induce more than 80% of complete remission and is also effective in relapsed patients. Rituximab after 2-CdA treatment can obtain a molecular response in most cases. The introduction of purine analog, and recently of Rituximab, in association with conventional chemotherapy can modify the clinical course of the disease with low toxicities.