[Renal cell carcinoma discovered in a patient with typical acute pyelonephritis: a case report].

A case of renal cell carcinoma that was discovered in a patient with typical acute pyelonephritis is reported. A 62-year-old woman admitted with fever and right flank pain, was diagnosed as having acute pyelonephritis. Intravenous urography showed a compressed renal pelvis and mild dilated calyces, suggesting the existence of a tumor. Computed tomography revealed a parapelvic tumor 6 cm in diameter and a small low-density area separated from the tumor in the renal parenchyma. Selective renal arteriography revealed a typical renal cell carcinoma lesion. The patient underwent right radical nephrectomy, and her postoperative course was uneventful. She has remained free of disease for 7 months.