Peritoneal carcinomatosis in patients with advanced bladder cancer is a rare but lethal event following robot-assisted radical cystectomy (RARC). We report a case of an unusual clinical course in which peritoneal dissemination of colon cancer was unexpectedly detected seven months after RARC.
A 67-year-old man underwent two courses of neoadjuvant chemotherapy and subsequent RARC with extracorporeal urinary diversion for muscle-invasive bladder cancer. The pathological diagnosis of the RARC specimen was urothelial carcinoma in situ (ypTis). After 7 months, the patient developed small bowel obstruction and underwent laparotomy. Intraoperatively, numerous seeding nodules were observed in the pelvic cavities, involving the small intestine. Contrary to our expectation of bladder cancer recurrence, the pathological examination revealed adenocarcinoma, suggesting primary colorectal cancer.
Peritoneal dissemination occurring shortly after RARC is often considered due to bladder cancer. However, the possibility of metastasis from other cancers must be taken into consideration.
IJU case reports. 2026 Mar 09*** epublish ***
Kana Ito, Ryo Yamashita, Shunsuke Kasai, Yuma Sakura, Hideo Shinsaka, Masafumi Nakamura, Masato Matsuzaki, Masashi Niwakawa, Takashi Sugino
Division of Urology Shizuoka Cancer Center Shizuoka Japan., Division of Colon and Rectal Surgery Shizuoka Cancer Center Shizuoka Japan., Division of Pathology Shizuoka Cancer Center Shizuoka Japan.