Objective      To evaluate the efficacy of endoscopic submucosal tunneling dissection (ESTD) in the treatment of esophageal submucosal tumor (SMT) originating from the muscularis propria.        Methods      The patients with esophageal SMT originating from the muscularis propria received ESTD in Xinqiao Hospital of Third Military Medical University from August 2011 to Jun 2014

and the data of the tumors and procedures were recorded carefully. All the patients were followed-up.       Results      Fifty-four cases of tumors were removed completely with ESTD

and 4 cases of tumors underwent surgical resection because the tumor had the transverse diameter greater than 3.5 cm and could not be taken out completely. The dissected specimens had the length of 0.8-8.5 cm (mean 2.55 cm)

and the transverse diameter of 0.5-3.0 cm (mean  1.65 cm). The operation time of ESTD was 20 to 280 min

and the mean time was 68 min. There were 11 cases (20%) with subcutaneous emphysema

3 cases (5.6%) with perforation

and 1 case (1.8%) with a little of free gas under the diaphragm by X-ray examination

and all of them were recovered uneventfully after conservative treatment. Histological examination confirmed the diagnosis of leiomyoma. Both the lateral and basal margins of the specimens were free of tumor cells. No pneumothorax or submucosal hematoma happened. No tumor residual or recurrence was found during follow-up by endoscopy and endoscopic ultrasonography

and the follow-up median period was 12 months (ranging in 1-24 months).       Conclusion      ESTD retains the normal mucosa to cover the wound and then reduces the risk of perforation. ESTD has little injury and high precision and is a safe and effective procedure for treating esophageal SMT originating from the muscularis propria.