| Submucosal tumors or subepithelial tumors (SETs) of gastrointestinal (GI) tract are mesenchymal neoplasms arising from cells beneath epithelium. The etiologies of SETs include gastrointestinal stromal tumor, leiomyoma, lipoma, lymphangioma, aberrant pancreas, schwannoma, and even mucosal malignancy infiltrating as a submucosal mass. The histology is difficult to be determined by merely endoscopy, endoscopic ultrasound (EUS) or cross-sectional images. Traditionally, for undetermined SETs smaller than 2 cm, regular surveillance was suggested based on weak and low quality evidence. However, the cut-off value of tumor size for malignant potential is inconclusive and the accuracy of histology prediction by EUS morphology is unsatisfactory. Therefore, tissue acquisition is important to stratify risk of patients with GI SETs. There is no consensus for gastroesophageal junction (GEJ) SETs. Conventionally, the techniques for tissue acquisition of GEJ SETs include stacked/bite-on-bite/mucosa incision with forceps biopsy, and EUS-guided fine needle aspiration or biopsy. Nevertheless, diagnostic yield is not high and higher risk for bleeding is noticed by forceps biopsy and the diagnostic yield of EUS-guided tissue acquisition is influenced by many factors. Recently, significant advances in endoscopic resection technique have been made, particularly the application of third-space endoscopy, submucosal tunneling endoscopic resection (STER), for SETs removal. By such procedures, GEJ SETs could be retrieved for definite pathological diagnosis with curative intents. The adverse event rate from STER is not high and most of the gas related complications could be managed conservatively by needle puncture for carbopneumoperitoneum. In this lecture, I will discuss about the importance and technique of tissue acquisition for GEJ SETs and provide possible approaching algorithm as well. |
