Ileorectal fistula due to a rectal cancer-A case report.

A 51-year-old man was seen at our hospital because of diarrhea. Barium enema and colonoscopy revealed a cancer in the lower rectum and fistula formation from the site to ileum. Resection of the rectal cancer and ileorectal fistula was performed. Histologically, the resected lesion was mucinous adenocarcinoma with contiguous invasion from the rectum to the ileum. The patient is alive with no sign of recurrence 120 months after operation. Fistula formation between the colon and other gastrointestinal tract organs is very rare, especially for rectal cancer. Fistula-forming colorectal cancers are rarely found to have metastatic lesions in the liver, peritoneum and lymph nodes despite their invasive behavior; accordingly, curative resection involving partial resection of the intestine with fistula is expected.