Endoscopic submucosal tunnel dissection of upper gastrointestinal submucosal tumors: A comparative study of hook knife vs hybrid knife

Figure 1 Illustration of endoscopic submucosal tunnel dissection for esophageal submucosal tumor in a patient using a hook knife. A: An submucosal tumor (SMT) located at the left lateral wall of the mid esophagus; B: Endoscopic ultrasonography revealed a 32.8 mm × 14.7 mm hypoechoic submucosal lesion; C and D: A 2-cm longitudinal incision is made into the mucosa after injection of natural saline with indigo carmine and epinephrine; E: After a mucosal incision was made, submucosal dissection was made approximately 4 cm proximal to the SMT with a hook knife, creating a submucosal tunnel until the tumor was visible; F: Dissection was done along the margin of the tumor; G: Endoclips were used to close the entry of the submucosal tunnel; H and I: Pathological examination revealed that the resected specimen was a 28-mm leiomyoma.