Colonic diverticulosis is a common disease, and the coexistence of colonic diverticulosis and colorectal cancer is often seen clinically. It is very rare that colon cancer arises from the mucosa of a colonic diverticulum. When colon cancer arises in a diverticulum and then tends to develop outside the wall, without developing within the lumen, the differential diagnosis from complicating lesions due to colonic diverticulitis is difficult.

A 76-year-old man was admitted to a nearby clinic with a chief complaint of discomfort and urinary frequency. Since a vesicosigmoidal fistula was seen on abdominal computed tomography, he was referred to our hospital. Laparoscopic sigmoidectomy was performed because the various diagnostic findings were diagnosed as a vesicosigmoidal fistula with diverticulitis of the sigmoid colon. However, on histopathological examination, it was diagnosed as a vesicosigmoidal fistula due to colon cancer arising in the diverticulum. Laparoscopic partial resection of the bladder was performed because local recurrence was observed in the bladder wall one and a half years after surgery. It is currently one year after reoperation, but there has been no recurrence or metastasis.

Colon cancer arising in a diverticulum of the colon should be considered when diverticulitis with complications is observed.

• Colon cancer
• Diverticulum
• Colovesical fistula
• Laparoscopic surgery
• Diverticulitis
• Case report

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.

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.

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.

In 2006, while admitted in our hospital for surgical treatment of recurrent diverticulitis, a 54-year-old man was found to have an adenocarcinoma arising within a colonic diverticulum. Computed tomography, during this episode of diverticulitis, showed a thickened wall of the sigmoid and inflammatory induration of the pericolonic fat. Colonoscopy could be performed up to no more then 25 cm from the anus due to mucosal edema. A sigmoid resection was performed. Histopathological examination of the resected specimen showed an inflamed diverticulum with a submucosal adenocarcinoma of the intestinal type within its wall. The surrounding flat colonic mucosa was not involved by the cancerous process. Due to lymph node involvement the patient received adjuvant chemotherapy and remained disease free during follow up.

• adenocarcinoma
• colon
• diverticulum

Collision tumors of the colon are rare. We report the first case, to our knowledge in the English literature, of a collision tumor composed of a colonic adenocarcinoma arising in a sigmoid diverticulum coexisting with a recurrent ovarian granulosa cell tumor.

A 64-year old woman presented with small bowel obstruction and a large, heterogenous, solid/cystic serosal based pelvic mass consistent with a gastrointestinal stromal tumor on imaging. Her significant past history 16-years ago included a bilateral salpingo-oophrectomy with hysterectomy. Surgical removal of the mass and pathological examination revealed the presence of a colonic adenocarcinoma arising in a large sigmoid diverticulum coexistent with a second neoplastic tumor phenotype; confirmed to be a delayed recurrent ovarian granulosa cell tumor. Though coexistent, the two tumor phenotypes respected their boundaries with no diffuse intermingling or transition between them. She developed lung metastases from the recurrent ovarian tumor within 6 months and died within a year of follow-up.

Collision tumors of the colon are rare. This is the first case reported of a collision tumor composed of adenocarcinoma colon and recurrent granulosa cell tumor representing an example of two independent tumors in a unique one-on-another collision. Clinical awareness and recognition of such tumors are important as they will dictate appropriate treatment strategies dependent on the individual biological aggressiveness of each of the tumor components. Our report highlights the need for histopathologists, surgeons, and oncologists to be aware of the rare possibility of collisions tumors. As seen in our case, the delayed recurrence of granulosa cell tumor of the ovary sixteen years after the initial presentation was the key determining factor in tumor recurrence, tumor progression, and tumor metastasis within three months, which ultimately lead to accelerated death within a year of clinical presentation. Thus accurate identification and recognition of the second neoplasm is important as prognosis and survival may be determined by this component as seen in our index case.

• Adult
• Age Factors
• Aged
• Aged, 80 and over
• Cohort Studies
• Colonic Neoplasms/complications
• Colonic Neoplasms/drug therapy
• Colonic Neoplasms/mortality
• Diverticulum, Colon/epidemiology
• Diverticulum, Colon/etiology
• Female
• Fluorouracil/administration & dosage
• Humans
• Leucovorin/administration & dosage
• Male
• Middle Aged
• Neoplasm Staging
• Prognosis
• Retrospective Studies
• Tegafur/administration & dosage

• U10CA-12027 NCI NIH HHS
• U10CA-37377 NCI NIH HHS
• U10CA-69651 NCI NIH HHS
• U10CA-69974 NCI NIH HHS

• Bile Duct Neoplasms/pathology
• Bile Ducts, Intrahepatic
• Carcinoembryonic Antigen/blood
• Cholangiocarcinoma/secondary
• Colonic Neoplasms/pathology
• Humans
• Immunohistochemistry
• Keratin-20
• Keratin-7
• Keratins/metabolism
• Male
• Middle Aged
• Sigmoid Neoplasms/secondary

• Adenoma, Villous/diagnosis
• Adenoma, Villous/pathology
• Adenoma, Villous/surgery
• Aged, 80 and over
• Colonic Neoplasms/diagnosis
• Colonic Neoplasms/pathology
• Colonic Neoplasms/surgery
• Diverticulum/complications
• Humans
• Intestinal Perforation/etiology
• Male
• Treatment Outcome