Clinical outcomes of underwater endoscopic mucosal resection for esophageal subepithelial tumors.

Esophageal submucosal tumors are increasingly identified through routine upper endoscopy, often performed as part of health screenings. Although many of these lesions are benign, some have malignant potential, necessitating accurate diagnosis and appropriate resection. Underwater endoscopic mucosal resection (UEMR) has gained attention as a novel technique that enables mucosal resection without submucosal injection, offering advantages in terms of safety and efficacy. However, data regarding its use for esophageal submucosal tumors are limited. This retrospective single-center study included 31 patients who underwent UEMRs for esophageal submucosal tumors between 2020 and 2024. The inclusion criteria were lesions <15 mm in diameter, confined to the submucosal layer, as confirmed by endoscopic ultrasound. Clinical variables, including age, sex, lesion characteristics, procedural details, and histopathological findings, were reviewed. Outcomes included en bloc and pathological complete (R0) resection rates, complications, and recurrence during follow-up. Among the 31 patients (mean age: 57.0 ± 12.5 years; 61% male), the most common lesion location was the lower esophagus (45.2%). Most lesions measured 5 to 10 mm (51.6%). Histopathologic diagnoses included leiomyomas (38.7%), granular cell tumors (32.3%), inflammatory fibroid polyps, and other benign entities. All lesions were resected en bloc using UEMR, with a 100% R0 resection rate. No major complications, including bleeding or perforation, occurred. During a follow-up period of up to 37 months, no recurrence was observed, including in cases of granular cell tumors or adenoid cystic carcinomas. UEMR is a safe and effective technique for managing esophageal submucosal tumors, demonstrating high en bloc and R0 resection rates with no major complications. These findings support UEMR as a favorable option for the resection of small esophageal submucosal tumors, providing a rationale for further prospective studies comparing UEMR with conventional endoscopic mucosal resection, band ligation-assisted endoscopic mucosal resection, and endoscopic submucosal dissection.