Malignant potential of chronic ulcerative colitis. Preliminary report.

Prior studies confirm the increased incidence of carcinoma of the colon in chronic ulcerative colitis. The authors reviewed clinical and histologic data retrospectively in 23 patients with colon carcinoma and chronic ulcerative colitis. Twenty-two of these patients had dysplasia of colonic epithelium remote from the cancer. The authors prospectively reviewed clinical data and rectal and colonoscopic biopsy specimens on 36 patients with chronic ulcerative colitis, 12 with Crohn's colitis, and 12 with miscellaneous disorders. Eight patients with chronic ulcerative colitis had dysplasia; 6 have had colectomy, and 2 of these had carcinoma. No patient without chronic ulcerative colitis had dysplasia. Patients with chronic ulcerative colitis should have periodic rectal and colonoscopic biopsies, and those with moderate to marked dysplasia require colectomy because of the increased risk of colon carcinoma.