Villous dysplasia. An ominous histologic sign in colitic patients.

Preoperative biopsies and colectomy specimens from 40 patients with long-standing ulcerative colitis (of whom 20 had adenocarcinoma at colectomy) were searched for the presence of villous adenomatous changes with or without cellular dysplasia. Villous adenomatous changes were found in available preoperative punch biopsies in nearly 70 per cent of the patients with carcinoma, but in none of the preoperative punch biopsies from the 20 patients without cancer. Only three of the preoperative biopsies from patients with carcinoma showed severe dysplasia, and also one of the 20 colitic patients without carcinoma. The mucosal tip in villous adenomatous changes was usually covered by columnar epithelium without dysplasia. In preoperative punch biopsies from patients with long-standing ulcerative colitis, the presence of structures compatible with villous adenoma--even those without cellular dysplasia--should be considered an ominous histologic sign and, thus, an indication for panproctocolectomy.