Splenic lymphoma with circulating villous lymphocytes: report of seven cases and review of the literature.

Splenic lymphoma with villous lymphocytes (SLVL) is a relatively new entity with only a few reports published. We report seven cases of SLVL with detailed clinicopathologic and comprehensive immunophenotypic studies to further characterize this lymphoma, which is frequently confused with hairy cell leukemia and other low-grade B-cell lymphoid neoplasms. The diagnostic criteria we used include 1) prominent splenomegaly, 2) insignificant or no lymphadenopathy, 3) lymphocytosis without leukopenia, 4) presence of circulating villous lymphocytes, 5) characteristic cytologic and histologic features, and 6) specific phenotypic and cytochemical findings. Our studies show that SLVL does not represent a pure entity but rather a morphologically heterogeneous group of low-grade lymphomas with various cytologic and histologic features. Although immunophenotyping is helpful in differential diagnosis, multiparameter studies are necessary to confirm the diagnosis. In our series, only two patients died of SLVL, who probably developed transformation to a higher-grade lymphoma.