Minute lesions of the rectum and sigmoid colon in patients with Crohn's disease.

Sigmoidoscopy with a spray of 0.1% indigocarmine was performed on 20 patients with Crohn's disease whose main lesions were located proximal to the transverse colon and on 10 age-matched healthy volunteers. Minute lesions such as apthoid lesions, areas of erythema, and small ulcers were found in 90% of patients with Crohn's disease and in 0% of healthy volunteers (p less than 0.001). Among the minute lesions, aphthoid lesions were found in the highest incidence (85%). It was difficult to determine the presence of aphthoid lesions without the spray of indigocarmine, which facilitated detection. Histologically, granulomas were found in 15% of patients with Crohn's disease. Aphthoid lesions were not associated with superficial erosions and lymphoid follicles. The presence of aphthoid lesions in the rectum and sigmoid colon would be a strong indication of the presence of Crohn's disease.