Colonoscopy and the detection of dysplasia in patients with longstanding ulcerative colitis.

The role of colonoscopy in the surveillance of patients with ulcerative colitis for dysplasia was investigated in 43 patients with longstanding disease extending proximally beyond the splenic flexure. The examination was well tolerated and no complications were recorded. Dysplasia was found in 9 patients in one or more biopsies and was severe in 2, moderate in 1, and mild in 6. Both the patients with severe dysplasia had a carcinoma at subsequent operation. Colonoscopy may allow complete examination of the colon and biopsy of suspicious lesions and, since dysplasia may spare the rectum, colonoscopy with biopsy is a desirable component of any surveillance programme of the at-risk colitic.