Mucinous adenocarcinoma of the colon metastatic to the intestinal mucosa.

Autometastasis of colon cancer to the intestinal mucosa is a condition that has not been previously described. The 70-year-old man presented in this case report was seen for routine surveillance colonoscopy 14 months after low anterior resection, without anastomosis, of a Dukes' stage C mucinous adenocarcinoma of the rectosigmoid. The patient had received adjuvant chemotherapy according to Southwest Oncology Group protocol 8899. The routine colonoscopy revealed many new polypoid lesions in the remaining left and transverse colon, and the patient underwent completion total abdominal colectomy. Examination of the specimen revealed more than 100 polyps; the histologic examination identified these polyps as metastatic signet ring mucinous adenocarcinoma.