Schematic illustration of the modified endoscopic submucosal dissection for subepithelial tumor originating from the muscularis propria layer. a. Subepithelial tumor; SM (submucosa); MP (muscularis propria). b. A longitudinal incision made by insulated-tip knife 2. c. Transverse incision made (orange peeling method). d. Tumor exposed after lateral dissection. e. Tumor was finally dissected by insulated-tip knife 2, or f. By snare polypectomy (at the fundus).