A 61-year-old male with no relevant past medical history underwent a colonoscopy for routine screening of colorectal cancer. Colonoscopy revealed a pearly and hard submucosal lesion of less than 10 mm in diameter in the ascending colon, with normal mucosa. An abdominopelvic computed tomography (CT) scan was performed, which was normal. Endoscopic submucosal dissection (ESD) was performed and the lesion appeared to originate from the muscularis propia. Thus, the muscularis propia and part of the serosa of the colonic wall were cut and the perforation was finally closed with hemoclips.