[Ewing's sarcoma in the retroperitoneum].

The patient was a female aged 18. Hematuria was discovered at an examination two years previously at which time the patient was complaining of right lumbar pain. The patient visited our hospital with a chief complaint of right abdominal tumor in June, 1988. A retroperitoneal tumor, 77 X 45 mm in size, was observed by CT and ultrasonic examination, and the right kidney was in hydronephrosis. An operation was performed in September, 1988, based on a diagnosis of retroperitoneal tumor and hydronephrosis. The tumor was seen to have involved the right ureter. Subsequently the tumor was surgically removed; right total nephroureterectomy and partial cystectomy were performed at that time. The removed tumor was 90 X 70 mm in size and 120 g in weight; it was histopathologically diagnosed as extraskeletal Ewing sarcoma. A systemic examination was carried out postoperatively, but no abnormalities were observed. As of September, 1990, the patient had had no recurrence and was being kept observation on an outpatient basis. There have been a total of 210 case reports regarding extraskeletal Ewing sarcoma published worldwide, including our case and 26 cases in Japan, so far as we know. However those of a lesion of retroperitoneal origin are extremely rare, numbering only 11 cases worldwide and 2 Japan. Herein we report our case of extraskeletal Ewing sarcoma with reference to the other 209 cases reported in the literature to date.