Splenic lymphoma with villous lymphocytes: diagnosis by flow cytometry and immunocytochemistry.

Splenic lymphoma with villous lymphocytes (SLVL) is a recently described low-grade non-Hodgkin's lymphoma that may be confused with chronic lymphocytic leukemia and hairy cell leukemia. Herein we report a case of SLVL and show how clinical features, cellular morphology, and flow cytometric analysis are used to distinguish among these three disorders. A newly developed immunocytochemical technique that allows detection of tartrate-resistant acid phosphatase on formalin-fixed, paraffin-embedded specimens was useful in refining our diagnosis of SLVL. Establishing the precise diagnosis is important because treatment is different for each of the three chronic lymphoproliferative malignancies.