Fig. 2From: A rare endoscopic appearance of granulomatosis with polyangiitis involving the intestine: a case reporta and b A black annular membrane, which was tunnel-like, allowing the colonoscopy to pass through. There are scattered erosions and ulcers at the bottom (H&E × 20). c Degenerative colonic mucosal tissue: only have contours. d Inflammation granulation tissue: no normal colon glands (H&E × 10)Back to article page