sentences:  The colonoscopy is normal but histology of the mucosal biopsy reveals an accumulation of lymphocytes in the colonic epithelium and connective tissue (lamina propria).Collagenous colitis shares this feature but additionally shows a distinctive thickening of the subepithelial collagen table.Budesonide, in colonic release preparations, has been shown in randomized controlled trials to be effective in treating this disorder.