1086 Using the Light at the End of the Tunnel: Salvaging a Submucosal Tunnelling Endoscopic Resection (STER) for Large Submucosal Lesions

A 32 year old female with dysphagia was referred for management of a submucosal gastric cardia mass 1 cm distal to the gastro-esophageal junction. Fine needle aspiration revealed possible gastro-intestinal stromal tumor or leiomyoma. The patient was referred for surgery. However, given the anatomic location, a complicated wedge resection with high risk of morbidity would need to be performed. Therefore, the patient was referred to our institution for endoscopic management. Given the symptoms, location and morbidity associated with surgical management, the decision was made to pursue submucosal tunneling endoscopic resection (STER). The patient was brought to our endoscopy suite and preparations were made for STER. An esophageal mucosal bleb and proximal mucosotomy was created 5 cm proximal to the lesion to gain access to the submucosa. The tunnel was extended through the esophagus into the gastric mucosa, where the smooth, encapsulated mass was encountered. Careful endoscopic dissection was performed to separate the lesion from the surrounding submucosal space. However, during this dissection, an inadvertent distal mucosotomy was noticed at the end of the tunnel. Given patient stability, the submucosal dissection was continued until the mass was completely dissected. However, the mass was larger than the diameter of the tunnel, making retrieval difficult. In order to remove the lesion, the inadvertent distal mucosotomy was intentionally lengthened. The encapsulated lesion was then gently pushed through the distal mucostomy into the stomach using the gastroscope. The proximal and distal mucosotomies were then closed. Upon retrieval, the mass measured 4 cm. Final pathology revealed a leiomyoma with negative margins. The patient was discharged the following day and was asymptomatic on follow up. Large gastric cardia lesions can be difficult to manage given the anatomic location. STER offers a possible endoscopic method for lesion removal. However, ensuring the tunnel is adequate for lesion removal can be difficult. Creation of a proximal and distal mucosotomy can aid in the removal of these large lesions.