A type of microscopic colitis of unknown etiology. it is characterized by the presence of collagen deposits in the lamina propria of the colonic mucosa. patients present with chronic watery diarrhea. colonoscopy reveals normal-appearing mucosa. the diagnosis is made with the microscopic examination of the colonic biopsy samples.

Collagenous colitis is an inflammatory condition of the colon. Together with the related condition lymphocytic colitis, it is a subtype of microscopic colitis, which is characterized by inflammation that specifically affects the colon (i.e...