The variable appearance of gut-associated lymphoid tissue at videocolonoscopy has not been well documented. Over a 3-year period all patients undergoing high resolution videocolonoscopy underwent biopsy of any identified abnormalities for correlating histopathologic findings with endoscopic appearance. We identified several distinct patterns for lymphoid tissue: Small well-circumscribed nodules, red rings, large coalescing vesicles with or without central pits, or white plaques. A mass-like appearance of the ileocecal valve was present in one patient. Although individually each of these patterns appeared characteristic, overall, variability appeared dependent on the colonic location and underlying disease. Prominent lymphoid tissue was most frequently seen in patients with underlying disorders resulting in stimulation of the immune system. We take this to mean that there is a broader spectrum of colonic lymphoid tissue as assessed by videocolonoscopy than previously appreciated. The variability of these normal structures has potential diagnostic implications. © 1994 Raven Press, Ltd., New York.