Colonoscopic biopsies and cytological examination in chronic ulcerative colitis.

Both multiple colonoscopic biopsies and brushing specimens for detection of any premalignant epithelial lesion were taken in 50 patients with long-standing ulcerative colitis. In 25 of the cases centrifuge sediment of enema return before the endoscopy was examined cytologically. The three methods were compared with respect to yield of colonic epithelium and occurrence of epithelial atypia. Enema return contained only a little glandular epithelium, which showed no atypical changes. Both biopsy and brushing yielded an abundance of epithelium. Biopsies showed a considerably higher frequency of epithelial atypia, especially of mild degree, and in two cases precancerous lesions were demonstrated only in the biopsies. In seven cases, on the other hand, moderate or severe atypia was found in brushing specimens when biopsies only revealed mild reactive changes.