Crohn's disease-associated carcinoma. A poorly recognized complication of inflammatory bowel disease.

We have reviewed eight cases of Crohn's disease associated carcinoma (CDAC) of the bowel treated at Saint Barnabas Medical Center since 1977. Five patients had colorectal carcinoma in areas of dysplasia within histologically recognizable Crohn's disease. One of the large bowel carcinomas was a diffusely infiltrating signet ring adenocarcinoma (linitis plastica), three were mucinous carcinomas, and one contained both cell types. Survival ranged from 4 to 55 months. Three patients developed ileal carcinomas in areas of dysplasia within histologically recognizable Crohn's disease. One of the ileal cancers was a moderately differentiated adenocarcinoma; two were poorly differentiated adenocarcinomas. Survival ranged from 8 to 44 months. The dysplastic changes seen in the bowel adjacent to the tumors in these patients were identical to the characteristic pre-cancerous (dysplastic) changes well described in ulcerative colitis. The histopathologic changes seen in this high-risk group of patients are also similar to those of previously reported CDAC. Those patients with the more diffuse dysplastic changes might have been detected before the development of invasive cancer had they undergone periodic colonoscopic surveillance. One patient in the series with an asymptomatic lesion was, in fact, identified at surveillance colonoscopy. It would appear that Crohn's disease patients have a similar risk for carcinoma previously recognized in ulcerative colitis patients and that surveillance protocols should be developed for this group of patients.