A 51-year-old woman had splenomegaly and enlarged multiple splenic hilar lymph nodes. The patient was referred to our department for F-18 fluorodeoxyglucose positron emission tomography/computed tomography (F-18 FDG PET/CT) evaluation to determine the metabolic activity of lymph nodes and define a biopsy site. PET/CT images showed diffuse increased FDG uptake in an enlarged spleen and hypermetabolic splenic hilar lymph nodes. The metabolic activity in bone marrow also seemed diffusely increased. After splenectomy, histopathologic analysis showed the growth of Leishmania amastigotes in splenic tissue, and bone marrow biopsy did not reveal any significant pathology but only mild hypercellularity.