[Primary adenocarcinoma of the seminal vesicle difficult to differentiate from rectal carcinoma : a case report].

: A 78-year-old man with urinary retention visited our hospital in June 2011. He presented with intestinal bleeding one month later and was admitted immediately. Contrast enhancement computed tomography revealed a lobulated intrapelvic tumor and liver metastasis. The prostate specific antigen level was normal, but his carcinoembryonic antigen level was elevated. Based on these results, his tumor was diagnosed as rectal carcinoma. On day 26, total pelvic exenteration and pelvic lymph node dissection to arrest bleeding were performed. We created an ileal conduit for urinary diversion and performed a sigmoid colostomy. The final histopathological assessment confirmed that he had primary adenocarcinoma of the seminal vesicle. The patient received the best supportive care because he rejected postoperative adjuvant chemotherapy and hormonal therapy. He died three months postoperatively. Primary adenocarcinoma of the seminal vesicle is very rare. The prognosis for this carcinoma is poor.