Japanese Society of Internal Medicine Acta Medica Okayama 0918-2918 64 20 2025 Two Cases of Esophageal Mucosal Damage Observed after Peroral Endoscopic Myotomy for Esophageal Motility Disorders 2979 2984 EN Shoichiro Hirata Department of Gastroenterology and Hepatology, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences Tomohiro Kamio Department of Gastroenterology and Hepatology, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences Takuya Satomi Department of Gastroenterology and Hepatology, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences Kenta Hamada Department of Practical Gastrointestinal Endoscopy, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences Hiroyuki Sakae Department of Gastroenterology and Hepatology, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences Masaya Iwamuro Department of Gastroenterology and Hepatology, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences Seiji Kawano Department of Gastroenterology and Hepatology, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences Yoshiro Kawahara Department of Practical Gastrointestinal Endoscopy, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences Noriaki Manabe Division of Endoscopy and Ultrasonography, Department of Clinical Pathology and Laboratory Medicine, Kawasaki Medical School Motoyuki Otsuka Department of Gastroenterology and Hepatology, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences This report presents two cases of esophageal mucosal damage following peroral endoscopic myotomy (POEM) for esophageal motility disorders. In the first case, delayed perforation and mediastinitis occurred on postoperative day 15 and the patient was treated with endoscopic clipping and antibiotics. In the second case, although no perforation was observed, extensive mucosal injury developed the day after POEM which was successfully managed by fasting and antibiotic therapy. These findings highlight the need for careful patient management to minimize the risks associated with POEM, while maximizing its therapeutic benefits. No potential conflict of interest relevant to this article was reported.