Congenital Esophageal Muscularis Propria Defect Found during Endoscopic Submucosal Dissection for Early Esophageal Cancer: A Case Report and Management.

Congenital esophageal muscularis propria defects are extremely rare, often complicating endoscopic submucosal dissection (ESD) for esophageal neoplasms. We report a 60-year-old man with early esophageal squamous cell carcinoma who underwent ESD. Intraoperatively, a congenital muscularis propria defect was incidentally identified as a translucent, respiration-synchronized submucosal membrane, which exposed mediastinal structures after perforation. The defect was successfully managed via endoscopic endoclip-nylon loop purse-string closure. The patient recovered uneventfully, with pathologically confirmed negative margins and no diverticulum or stenosis at 3-month follow-up endoscopy. This case highlights that timely endoscopic recognition and management of such defects during ESD can avoid surgical intervention and ensure favorable outcomes, providing practical insights for endoscopists.