With the widespread use of upper endoscopy, esophageal submucosal tumors (SMTs) are increasingly detected during routine health screenings. Underwater endoscopic mucosal resection (UEMR) has recently emerged as a novel approach that enables mucosal resection without submucosal injection, offering potential benefits in safety and efficacy. However, evidence on its application for esophageal SMTs remains limited.

This retrospective single-center study analyzed 31 patients who underwent UEMR for esophageal SMTs between 2020 and 2024. Eligible lesions were <15 mm in diameter and confined to the submucosal layer, as confirmed by endoscopic ultrasound (EUS). Demographic data, lesion characteristics, procedural details, and histopathologic results were reviewed. Primary outcomes included en bloc and pathological complete (R0) resection rates, with secondary outcomes assessing complications and recurrence during follow-up.

A total of 31 patients (mean age 57.0 ± 12.5 years; 61% male) were included. The lower esophagus was the most frequent tumor site (45.2%), and most lesions measured 5–10 mm (51.6%). Histopathological diagnoses comprised leiomyomas (38.7%), granular cell tumors (32.3%), inflammatory fibroid polyps, and other benign entities. All tumors were successfully removed en bloc using UEMR, achieving a 100% R0 resection rate. No major adverse events, including bleeding or perforation, occurred. During a median follow-up of up to 37 months, no local recurrence was observed, even among cases of granular cell tumor or adenoid cystic carcinoma.

UEMR appears to be a safe and effective option for the management of small esophageal SMTs, demonstrating excellent en bloc and R0 resection outcomes without significant complications. These results support UEMR as a favorable alternative for small esophageal SMTs.