Fig. 1
a Colonoscopy image showing a stricture in the lower rectum (white arrow). An endoscope of external diameter 9.9 mm could be passed, with resistance, through this stenosis. b Preoperative computed tomography–colonography image showing narrowing of the rectum at the stenosis (black arrow). c, d Magnetic resonance images showing rectal narrowing accompanied by muscular thickening (yellow arrow)