[Two cases of abdominal masses caused by foreign bodies which were preoperatively diagnosed as urachal abscess].

A 61-year-old man and a 59-year-old woman were referred to our hospital because of lower abdominal pain and discomfort, pollakisuria and a lower abdominal mass. In both patients, radiological studies and cystoscopy caused us to suspect a urachal abscess. We performed operations transperitoneally. In the male patient, fish bones were detected between the mass and ileum. A partial cystectomy was performed on the female patient, and the histological diagnosis was Sparganosis mansoni. In both cases, it was very difficult to make a correct diagnosis before the operations, but surgical treatment was successfully performed.