Fig. 3
From: Collagenous colitis presenting as spontaneous perforation in an 80 year old woman: Report of a Case
Microscopy of the resected colon: a and b Low power views (×12.5) of ulcerated bowel with abscess formation and transmural necrosis. Even at this low magnification the non-ulcerated mucosa shows clear evidence of collagenous colitis. c Medium power view (×100) of mucosal ulceration (left) and severe collagenous colitis (right). d High power view (×200) of the mucosa showing the features of collagenous colitis: a markedly thickened subepithelial collagen layer measuring up to 100 μm, surface epithelial flattening with loss of goblet cells, separation of the epithelium from the lamina propria, increased intraepithelial and lamina propria chronic inflammatory cells. e High power view (×200), Masson's trichrome stain, in which the thickened subepithelial collagen layer is stained blue. f Very high power view (×400) of multinucleated histiocytes