endoscopic resection of a giant pedunculated colonic polyp using a detachable snare and a scissor-type knife. Bleeding risk after polypectomy of large pedunculated polyps with thick stalk increases due to the possibility of large vessels in the stalk. The risk factors for post-polypectomy bleeding are polyp size more than 17 mm and stalk diameter more than 5 mm. So, the prophylactic strategies against bleeding should be implemented, such as prophylactic adrenaline injection, detachable snare placement, or prophylactic clip application. Here represents a case of a large pedunculated polyp after sigmoid colon that was challenging to place a detachable snare and resect due to its huge head and thick stalk. A 60-year-old male was presented with intermittent abdominal pain. Abdominal CT revealed colocolonic interception of the sigmoid colon with a 5 cm polypoid mass as the leading point. We performed colonoscopy and found a giant pedunculated polyp at the sigmoid colon. Magnifying NBI showed a type 2b genetic classification. The polyp had 50 mm head diameter and 20 mm stalk width. Due to the huge polyp size and thick stalk, we decided to apply a detachable snare around the stalk before resection. The detachable snare placement was challenging because of the huge polyp head and floppy loop. It was difficult to place the detachable snare around the stalk. Therefore, we altered the patient's position from the supine to the prone position to allow gravity to make the polyp head swing into the loop. Finally, we successfully placed the detachable snare around the stalk, then resected the polyp. We placed the detachable snare around the stalk, then tightened and deployed the snare. The polyp's color turned deep purple due to the ischemia. The stalk was shortened after detachable snare placement. So, we used an endoscopic knife to cut the stalk precisely, avoiding incomplete resection or loop detachment. A needle-type knife failed to cut the stalk because of the lack of traction. So, we changed it to a scissor-type knife which can precisely cut the stalk midway between the polyp and the detachable snare. During resection, there was backflow bleeding from the polyp. This is the final cut. The mucosal defect was closed using endoscopic clips. Specimen retrieval was difficult due to the vacuum effect of the large specimen. Therefore, we used the clip-line traction method with a re-openable clip and dental floss. The specimen was clipped at the stalk, then we pulled the specimen with this line simultaneously with carbon dioxide in separation to break the vacuum seal. Finally, the specimen was successfully retrieved. The procedural time was 45 minutes. The pathologic examination showed the tubulophilous adenoma with high-grade dysplasia and clear out root section margins. Clinical implications First, patient's position alteration could be helpful during the detachable snare placement of a large peduncleated polyp. Second, scissor-type knife allows precise dissection in a challenging situation with a short stalk after the detachable snare tightening. Third, to break the vacuum seal and retrieve the giant specimen, we pulled the specimen with clip-with-line traction method simultaneously with carbon dioxide in separation. In conclusion, endoscopic resection of a giant peduncleated polyp is safe and effective using a detachable snare and scissor-type knife. We demonstrated how the patient's position change facilitated the detachable snare placement, the precise dissection with the scissor-type knife, and the retrieval technique for huge specimen.

endoscopic resection

colonic polyp

detachable snare

scissor-type knife

large polyps