An 82-year-old woman was referred for endoscopic submucosal dissection (ESD) of a circumferential granular-mixed laterally spreading tumor in the ascending colon. Markedly redundant colon and sharp angulations due to adhesions of the descending colon were observed. After reaching the transverse colon with double-balloon endoluminal intervention platform (an accessory designed to maintain endoscope position and creation of a therapeutic zone), blood was observed inside the overtube. At the descending colon, a full-thickness colonic perforation was identified, with spleen visible intraluminally. Laceration was closed successfully with through-the-scope clips, without requiring pneumoperitoneum decompression (procedure under CO₂). The patient was treated with broad-spectrum intravenous antibiotics and had an uneventful recovery (discharged on postoperative day 4).