title: Sigmoid colon cancer arising in a diverticulum of the colon with involvement of the urinary bladder: a case report and review of the literature.
abstract: BACKGROUND
  Colon cancer can arise from the mucosa in a colonic diverticulum. Although colon diverticulum is a common disease, few cases have been previously reported on colon cancer associated with a diverticulum. We report a rare case of sigmoid colon cancer arising in a diverticulum with involvement of the urinary bladder, which presented characteristic radiographic images.
  
  
  METHODS
  A 73-year-old man was admitted to our hospital for macroscopic hematuria. Computed tomography and magnetic resonance imaging revealed a sigmoid colon tumor that protruded into the urinary bladder lumen. The radiographs showed a tumor with a characteristic dumbbell-shaped appearance. Colonoscopy showed a type 1 cancer and multiple diverticula in the sigmoid colon. A diagnosis of sigmoid colon cancer with involvement of the urinary bladder was made based on the pathological findings of the biopsied specimens. We performed sigmoidectomy and total resection of the urinary bladder with colostomy and urinary tract diversion. Histopathological findings showed the presence of a colovesical fistula due to extramurally growing colon cancer. Around the colon cancer, the normal colon mucosa was depressed sharply with lack of the muscular layer, suggesting that the colon cancer was arising from a colon diverticulum.
  
  
  CONCLUSIONS
  The present case is the first report of sigmoid colon cancer arising in a diverticulum with involvement of the urinary bladder. Due to an accurate preoperative radiological diagnosis, we were able to successfully perform a curative resection for sigmoid colon cancer arising in a diverticulum with involvement of the urinary bladder.
authors.affiliation: Department of Surgery, Toyama City Hospital, 2-1 Imaizumi Hokubu-machi, Toyama 939-8511, Japan. y-yagi@live.jp.
authors.forename: Yasumichi
authors.initials: Y
authors.lastname: Yagi
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Shoji
authors.forename: Shozo
authors.initials: S
authors.lastname: Sasaki
authors.forename: Akemi
authors.initials: A
authors.lastname: Yoshikawa
authors.forename: Yuji
authors.initials: Y
authors.lastname: Tsukioka
authors.forename: Wataru
authors.initials: W
authors.lastname: Fukushima
authors.forename: Hisashi
authors.initials: H
authors.lastname: Hirosawa
authors.forename: Ryohei
authors.initials: R
authors.lastname: Izumi
authors.forename: Katsuhiko
authors.initials: K
authors.lastname: Saito
mesh_terms: D000230:Adenocarcinoma / Q000000981:diagnostic imaging / Q000473:pathology* / Q000601:surgery; D000368:Aged; D001466:Barium Sulfate; D003287:Contrast Media; D004241:Diverticulum, Colon / Q000000981:diagnostic imaging / Q000473:pathology* / Q000601:surgery; D004733:Enema; D006801:Humans; D007412:Intestinal Fistula / Q000000981:diagnostic imaging / Q000473:pathology* / Q000601:surgery; D008279:Magnetic Resonance Imaging; D008297:Male; D009361:Neoplasm Invasiveness; D012811:Sigmoid Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology* / Q000601:surgery; D014057:Tomography, X-Ray Computed; D001743:Urinary Bladder / Q000000981:diagnostic imaging / Q000473:pathology* / Q000601:surgery
chemical_list: D003287:Contrast Media; D001466:Barium Sulfate