Retrovesical desmoplastic small round cell tumor in a patient with urinaryfrequency

A 21-year-old man with urological symptoms was found to have a large abdomi nal tumor in the retrovesical space between the bladder and the rectosigmoi d colon. Radiologic findings revealed little evidence confirming the diagno sis. A transrectal biopsy failed to disclose the histopathologic origin of the tumor. An exploratory laparotomy with a complete surgical resection was impossible, so a wedge biopsy was performed. Combined histologic and immun ohistochemical findings revealed the features of desmoplastic small round c ell tumor (DSRCT). Despite subsequent multiagent chemotherapy, the patient died as a result of the growing tumor and liver metastasis. There have been only two prior reports of this neoplasm in the urological literature.