Tropical splenomegaly syndrome in a nontropical setting.

Tropical splenomegaly syndrome, a rare complication of recurrent malarial infection thought to occur only in endemic areas, was diagnosed in a 9-year resident of the United States. The patient had splenomegaly, anemia, a history of recurrent fever since childhood, cryoglobulinemia, increased serum IgM, and elevated specific immunofluorescent antibody titers to Plasmodium falciparum. After antimalarial treatment and splenectomy, she became asymptomatic and the IgM levels and specific antibody titers returned to normal. Because of increased travel to and from endemic malarial areas, this syndrome should be considered in the differential diagnosis of chronic splenomegaly.