Retrovesical desmoplastic small round cell tumor in a patient with urinary frequency

A 21‐year‐old man with urological symptoms was found to have a large abdominal tumor in the retrovesical space between the bladder and the rectosigmoid colon. Radiologic findings revealed little evidence confirming the diagnosis. 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 immunohistochemical findings revealed the features of desmoplastic small round cell tumor (DSRCT). Despite subsequent multi‐agent 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.