Endoscopic tunneling and subserosal dissection using NODES approach for gastric subepithelial tumor. No relevant disclosures. Gastric subepithelial lesions can be endophatic or exophatic. Endoscopic full thickness resection and submucosal tunneling endoscopic resection are established techniques for endophatic lesions. Exophatic lesions are generally surgically resected and endoscopic resection has been rarely described. Our technique included submucosal gastric tunneling commencing proximal to the tumor and extending up to the distal margin followed by a proximal full thickness myotomy through the tunnel to enter the peritoneal cavity. Trans-tunnel peritoneoscopy to approach the lesion from the peritoneal aspect to achieve coagulation of the subserosal vessels and omental adigelysis followed by enucleation and resection. Our patient was a 74 year old female who was evaluated for epigastric pain. EGD and CT scan revealed a 4 by 3 centimeter exophytic lesion along the lesser curvature extending into the gastrohepatic space. Endoscopic ultrasound revealed the lesion arising from the fourth layer and fine needle biopsy confirmed disc with CKID positive. Patient was started on imatinib and three months later the lesion showed considerable reduction in size. Patient was now planned for endoscopic tunneling subserosal dissection. After submucosal elevation using a combination of normal saline and methylene blue, a transverse mucosal incision was taken 5 centimeters proximal to the tumor. A submucosal tunnel was created by submucosal dissection using a triangular tip knife up to the distal margin of the tumor. After completing the tunnel a full thickness myotomy was performed 3 centimeter proximal to the tumor. The endoscope was advanced through the myotomy. The gastric serosa with the overlying momentum was visualized. Serosal vessels were coagulated and the peritoneal layer was opened using coagulation forceps. The peritoneal incision was extended using an insulated tip knife. The endoscope was now advanced into the peritoneal cavity to perform peritoneoscopy. The tumor was seen to be covered by mental adhesions. Sub-serosal elevation was now achieved and the adhesions were gently dissected using a dual knife. Serosal vessels were prophylactically coagulated and divided. After releasing the adhesions and securing hemostasis on the serosal aspect, the tumor was now dissected carefully from the muscle layer. Dental floss enabled clip traction was now applied. Dissection was now continued in the deep muscle layer. Care was taken to prevent injury to the tumor capsule. An insulated tip knife proved useful for this purpose. When the tumor remained attached by a narrow muscle attachment, the insulated tip knife was replaced for a snare. The tumor was ensnared and resected, ensuring a continuous traction on the clip and line and on the snare to prevent it from falling into the peritoneal cavity. The tumor could not be retrieved through the muscle opening. The gastric myotomy was therefore extended and the tumor was then retrieved into the stomach. The resected specimen and the mucosal defect can be seen here. After confirming hemostasis, the mucosal incision was closed with an endoscopic suturing system using a double channel endoscope. This is the final appearance of the closed mucosal defect. The specimen was retrieved. A combination of a grasping forceps and snare through the double channel scope was used for this purpose. The resected specimen approximately measured 3 cm. Final histology revealed free margins and 70% viable tumor. The pathology recommended the patient to continue imatinib for 3 years with a CT scan planned after 6 months. Clinical Implications Potential risks for endoscopic resection of exophytic gastric sebepithelial lesions include intraperitoneal bleed from subserosal vessels, loss of tumor into the peritoneal cavity with the possibility of tumor seedling. By approaching the tumor through the tunneled proximal myotomy, we could control the subserosal vessels and using the clip and line traction and snare during the final steps of the resection prevented the tumor from being lost into the peritoneal cavity. The procedure imatinib helped to reduce the tumor size thereby enabling endoscopic resection. In conclusion, endoscopic tunneling subserosal resection is feasible and safe for resection of exophytic gastric sebepithelial lesions.

endoscopic resection

subepithelial tumors

submucosal tunneling

minimally invasive surgery

gastric tumor removal