A case of colonic stenosis caused by cold snare polypectomy for the removal of a colonic polyp.

A 78-year-old woman with hypertension had a positive fecal immunochemical test and underwent colonoscopy, which revealed a 4 mm sessile polyp (Paris type; 0-Is) in the transverse colon. Based on low magnification colonoscopy with narrow band imaging, the polyp was Type 2 according to the NBI International Colorectal Endoscopic classification, diagnosed as an adenoma, and then resected via cold snare polypectomy (CSP). Five days after CSP, she complained of right-sided abdominal pain. Abdominal CT showed focal wall thickening of the transverse colon and focal infiltration of tissues surrounding the transverse colon. The inflammatory lesion was considered to coincide with the location of the polyp resected with CSP. However, no inflammatory findings were seen in other parts of the colon, and intraperitoneal free air and ascites were not identified. Moreover, no inflammatory findings and no infectious signs in other organs were present. She was administered intravenous antibiotics and, 19 days later, she was discharged from our hospital. Approximately 3 months later, colonoscopy revealed colonic stenosis associated with red mucosa and ulceration in the transverse colon where the polyp had been resected with CSP. Contrast-enhanced X-ray revealed an approximately 1 cm-long colonic stenosis in the transverse colon near the hepatic flexure.