Paraneoplastic vasculitis associated with hairy cell leukemia.

Hairy cell leukemia (HCL) is a rare B-cell lymphoproliferative disease, accounting for about 2-3% of all leukemias in adults. The skin lesions were described in about 10-12% of patients. Vasculitis in lymphoproliferative disease is relatively uncommon and may predate the diagnosis of lymphoproliferative disease. A 54-year old female with one month history of general symptoms and sudden onset of maculopapular exanthema on the skin, suffered from anemia, leukopenia and thrombocytopenia. Examination of the skin biopsy revealed lymphocytic vasculitis. Immunophenotyping of the skin biopsy revealed cell population with CD45RO, and small groups with CD20, partly DBA44 positivity. Bone marrow trepanobiopsy showed 50% infiltration with medium-sized lymphoid cells with clear cytoplasm and immunophenotypic coexpression of CD20 and DBA-44 antigens. The diagnosis of HCL was confirmed by flow cytometry of the bone marrow and of the peripheral blood cells that revealed pathological cell population with expression of CD11c, CD19, CD25, CD103. The patient was successfully treated with a single dose of cladribrine. The patient with acute vasculitis should be screened and monitored for possible lymphoproliferative diseases. Skin manifestation of acute vasculitis accompanied with hairy cells may be the first manifestation of HCL. Purine nucleoside analogue cladribrine is considered as the first line of therapy for HCL and induces a total response in more than 80% of cases with HCL.