Submucosal tunneling endoscopic resection for an unusually sized esophageal submucosal tumor protruding into the mediastinum.

A 50-year-old female came to our hospital with a 6-month history of upper abdominal discomfort. An upper endoscopy detected a protruding lesion that measured 3.0×2.0 cm at around 35-38 cm from the incisors located on the posterior wall. Endoscopic ultrasonography revealed a homogeneous hyperechoic mass located in the muscularis propria, with no malignant features. Contrast-enhanced CT was also performed. A submucosal tunneling endoscopic resection (STER) was performed. A longitudinal mucosal incision was made and a submucosal tunnel created, which uncovered an irregularly giant tumor. The size of the resected tumor was 3.0×4.0×1.5cm and the histopathological analysis identified leiomyomas. The patient was discharged 7 days after the procedure and 3 months after the surgery there was no recurrence on the CT scan. Meanwhile, the discomfort of the patient was relieved after STER and there were no severe complications during the 6-month follow-up. DISCUSSION Esophageal leiomyoma is a benign submucosal tumor derived from the muscularis propria layer of the esophagus [1]. STER has been demonstrated to be safe and effective for treating small (≤3.5 cm) and solitary esophageal leiomyoma with low complication rates [2-3]. Most esophageal leiomyoma grow into the lumen and their positions in the tunnel are relatively superficial and the entire surgery is comparatively safe. In this case, the tumor was very large and was close to the mediastinum, which greatly increases the difficulty of surgery. However, STER is recommended according to our experience, even in rare cases.