Splenic lymphoma with villous lymphocytes should be included in the differential diagnosis of massive splenomegaly

Aim. To distinguish between patients with reactive lymphocytosis and those with malignant lymphoid proliferations, with particular reference to hyper-reactive malarial splenomegaly and splenic lymphoma with villous lymphocytes. Patients. Forty-four patients, residents of the Ashanti region of Ghana that is hyperendemic for Plasmodium falciparum malaria, were studied. All patients had splenomegaly greater than 10 cm. They were given proguanil 100 mg/day for a minimum of 6 months. Lymphocyte surface phenotypes were studied on the peripheral blood smears, immunoglobulin gene rearrangement by the Southern blot technique, serum IgM concentration using the Nor-Partigen-IgM kit, and serum paraprotein concentration by electrophoresis. Results. Based on the response to proguanil, the patients were categorized into good respondents, partial respondents, and non respondents. Peripheral blood lymphocytes exceeded 30% in 19, and villous lymphocytes were less than 30% in 25 patients. Conclusion. Splenic lymphoma with villous lymphocytes may be difficult to differentiate from the African variant of chronic lymphocytic leukemia which is associated with splenomegaly and from hyperreactive malarial splenomegaly with lymphocytosis. In West Africa, a peripheral blood lymphocyte count greater than 10 x 10⁹/L, with more than 30% of villous lymphocytes and failure of splenic regression with anti-malarial therapy suggest a diagnosis of splenic lymphoma with villous lymphocytes.