Crohn's disease and adenocarcinoma of the intestinal tract. Report of four cases. Four patients with intestinal adenocarcinoma complicating Crohn's disease are reported. The youngest of the four patients was a 21-year-old female with a 9-year history of Crohn's disease of the terminal ileum as well as of the entire colon. She developed mucus-producing moderately differentiated adenocarcinoma in the cecum. Of the remaining three patients with Crohn's disease, one presented an adenocarcinoma in the ascending colon, one in the rectum and the remaining one in the duodenum. All three colorectal adenocarcinomas originated in areas of high-grade dysplasia and all four in areas with chronic transmural inflammation. The review of the literature indicates that a total of 174 small and large bowel cancers occurring in Crohn's disease have been recorded (including the four reported herein). The vast majority of the reported cases have been found in the North American subcontinent. Only in a few instances were bowel adenocarcinoma and Crohn's disease observed in the European continent. It is therefore remarkable that three of our four cases were seen within a period of 12 months. Interestingly, six patients having colorectal adenocarcinoma in association with Crohn's disease were recently reported from a single hospital in England. The question therefore arises whether our cases and those reported recently from England are unrelated and merely coincidental or whether carcinomas are now also affecting European CD patients. If the latter is the case, the surveillance policy for patients with CD should be reconsidered at this hospital. 