The rapid growth of intraluminal tumor metastases at the intestinal wall sites damaged by obstructive colitis due to sigmoid colon cancer: report of a case.

A 53-year-old woman who was traveling in Australia was admitted to a local hospital with pyrexia and diarrhea. Megacolon was diagnosed from an X-ray and an emergency operation was performed. However, the cause of megacolon was not clear, and the attempted operation ended in a simple laparotomy. Sigmoid cancer was found 3 weeks after the first operation and a colostomy was performed at the ascending colon. After the second operation, she returned to Japan and was thereafter admitted to our hospital. Total colonoscopy before the third surgery (sigmoidectomy) revealed erosive mucosa but no tumor. The damaged mucosa in the proximal colon (compatible with a diagnosis of obstructive colitis) was found during a sigmoidectomy. Watery diarrhea and melena persisted after the third operation. Colonoscopy showed disseminated tumor nodules at the proximal colon of the anastomosis at 37 days after the third surgery. Finally, a subtotal colectomy and jejunal pouch reconstruction were carried out. The exfoliated malignant cells from the sigmoid colon appeared to form micrometastases in the mucosal sites damaged by obstructive colitis. In conclusion, in a case of obstructive colitis due to cancer, we must consider the possibility that the tumor may spread to damaged mucosal sites and grow intraluminally.