Hairy cell leukemia-variant (HCL-variant) is a rare B-cell disorder of hairy cell leukemia cases. The main features are splenomegaly, lymphocytosis and cytopenias without monocytopenia. Diagnosis is based on the distinctive hairy cell morphology and immunophenotype. Cells from hairy cell leukemia (HCL) and HCL-variant have a distinct immunophenotype which is of a mature but not terminally differentiated activated B-cell. We experienced a case of HCL- variant in a 50-year-old man with marked splenomegaly and skin eruptions. Peripheral blood smear showed abnormal lymphoid cells with cytoplasmic projections. The bone marrow was easily aspirated and showed hypercellularity and diffuse interstitial infiltration of hairy cells. Tartrate-resistant acid phosphatase (TRAP) reactivity was negative in the hairy cells. Immunophenotyping results of lymphoid cells were CD2 (-), CD3 (-), CD5 (-), CD7 (-), CD10 (-), CD19 (++), CD20 (+++), sKappa (-), sLambda (+), CD23 (-), CD25 (-), FMC7 (+) and CD103 (++).

Keywords: Hairy cell leukemia, Variant, Splenomegaly