Figure 1: Process of endoscopic submucosal dissection. (a) A laterally spreading, granular, homogenous type tumor, 5.5 cm in diameter, was noted at ascending colon. Fluid was injected into submucosal layer to create cushion for mucosal incision and submucosal dissection. (b) Dual knife was used for submucosal dissection along the blue layer that was caused by indigo carmine being administered to enhance dissection plane. (c) The tumor was already resected en bloc. The artificially created ulcer base was checked carefully for muscular layer injury and exposed vessel. (d) The resected specimen was stretched and fixed well on a plate.