Surveillance Colonoscopy (Cases of Small Intestinal Cancers in Crohn’s Disease, Cases of Anal Cancers in Crohn’s Disease)

Abstract

It has recently been recognized that long-standing Crohn’s disease (CD) is associated with an increased risk of carcinogenesis. Three types of gastrointestinal carcinomas occur more frequently in patients with CD than in the general population: cancers arising from small-bowel lesions, from colorectal lesions, and from peri-anal lesions, which include both stricturing and fistulizing lesions. However, cancer surveillance for CD has not yet been established, especially for small-bowel and peri-anal lesions. The difficulties of cancer diagnosis are illustrated by two case presentations. Case 1 involved a 16-year ileal stricture in a patient with CD who was admitted for bowel obstruction. He was diagnosed postoperatively as having poorly differentiated adenocarcinoma with peritoneal dissemination. Case 2 involved a 33-year history of an anal lesion with stricture in a CD patient who was diagnosed as having advanced as well as differentiated adenocarcinoma at the anal canal. Prior examinations every 3 months within 6 months could not detect the cancer. Cancer associated with Crohn’s lesions seems to be difficult to diagnose early. Although the diagnostic strategy remains unclear, carcinogenesis needs to be considered.