[A case of renal malacoplakia that was difficult to distinguish from cystic renal cell carcinoma].

A 66 years old man visited our hospital with a chief complaint of right flank pain and abdominal palpable mass. Abdominal enhanced computed tomography scan showed a large cystic mass with infiltrating surrounding tissue in the right kidney. We diagnosed it infected cystic renal cell carcinoma because of high grade fever and acute inflammatory response.