Splenic marginal zone lymphoma

A low-grade mature B-cell lymphoma that usually involves the spleen, peripheral blood and sometimes other organs such as the bone marrow. Characteristic features are splenomegaly (involving the white pulp of spleen as opposed to hairy cell leukemia which involves the splenic red pulp), moderate lymphocytosis with villous morphology (seen in the peripheral blood smear), and intrasinusoidal pattern of involvement of various organs, especially the bone marrow. Characteristic immunophenotype is similar to other marginal zone lymphomas (triple negative phenotype referring to being negative for CD5, CD10 and CD23).