Chronic ulcerative colitis complicated by atypical carcinoid tumour.

A malignant carcinoid tumour of the rectum was found in a patient who had chronic ulcerative colitis. It had a multifocal origin and had not been macroscopically apparent. This association has been recorded in the colon. Hyperplasia of enterochromaffin cells in ulcerative colitis and also dysplasia of these elements as part of a pancellular dysplasia may occur; and this may be a possible explanation for the development of a carcinoid tumour in this condition.