A 59-year-old patient with multiple myeloma on maintenance chemotherapy presented with fever, weight loss, and night sweats. An F-18 fluorodeoxyglucose (FDG) positron emission tomography (PET) computed tomography (CT) showed intra-abdominal lymphadenopathy with a mesenteric mass that led to further workup and diagnosis of histoplamosis. The patient was treated with amphotericin B and subsequently switched to itraconazole. This exemplifies the usefulness of FDG PET CT in diagnosis of infectious complications.