Brush cytology of the colon and rectum in ulcerative colitis: an aid to cancer diagnosis.

In a prospective study of 100 patients with ulcerative colitis, 82 of whom had extensive colitis, carcinoma and dysplasia were distinguished cytologically from reactive hyperplasia. Six patients had carcinoma complicating colitis and satisfactory samples were obtained from five; the cytological appearances were interpreted as carcinoma in three and as dysplasia in two. Seventy eight patients had not developed carcinoma or dysplasia; the cytological appearances were interpreted as negative for dysplasia in 75 and indefinite for dysplasia in three. In patients who had developed dysplasia the changes seemed to be more widespread on cytological rather than on histological examination. Brush cytology may complement histological assessment in patients with ulcerative colitis who have developed strictures or in whom there is a high suspicion of neoplastic change.