[Microscopic foci of urachal carcinoma in an incidentally detected urachal cyst: a case report].

A 33-year-old man who had been treated for chronic prostatitis was diagnosed to have urachal cysts by transabdominal ultrasonography. Cystoscopy revealed protuberance at the dome of the bladder. Computerized tomography scan and magnetic resonance imaging showed the mass to be mostly cystic but partly solid. Resection of the urachal cysts and partial cystectomy were performed. Histopathologically, most cysts had a normal cylindrical epithelium with retention of mucinous substance. However, several small cysts contained epithelial cells resembling tubulo-villous adenoma and showing mitotic figures. This case was concluded as urachal carcinoma detected in its very early stage.