[A case of renal actinomycosis].

A case of renal actinomycosis is reported. A 63-year-old man was admitted to our hospital for further examinations of a right renal mass, complaining of dull pain in his right loin and progressive weight loss. Laboratory findings showed an anemia with a grossly raised ESR, CT, MRI and ultrasonography revealed a solid mass of the right kidney. Chest CT films revealed several infiltrates in the bilateral lobes. A diagnosis of neoplasm or inflammatory mass of the right kidney was considered, and the right nephrectomy was performed. Microscopically, characteristic colonies of actinomyces were seen, and histological diagnosis was renal actinomycosis. The patient made good progress after operation and was subsequently treated with penicillin.