Successful Endoscopic Ultrasound‐Guided Transgastric Drainage for Intra‐Abdominal Abscess Caused by Delayed Perforation After Gastric Endoscopic Mucosal Resection

Delayed perforation after gastric endoscopic mucosal resection (EMR) is a rare but serious complication that can lead to intra‐abdominal abscess (IAA) formation. Efficacy of endoscopic ultrasound (EUS)‐guided drainage for IAA remains to be elucidated. A man in his 50s was admitted for EMR of hyperplastic polyps located in the gastric body. The procedure was performed uneventfully; however, on postoperative day (POD) 4, the patient developed a sudden fever accompanied by an elevation in inflammatory markers. Abdominal computed tomography (CT) revealed a localized area of increased fat attenuation, leading to a diagnosis of delayed perforation. The patient's condition temporarily improved with conservative therapy; however, fever and elevated inflammatory markers recurred on POD 17. CT demonstrated IAA requiring drainage. On POD 22, EUS‐guided transgastric drainage was performed using a nasobiliary drainage tube and double‐pigtail stent. After drainage, fever and inflammatory markers promptly alleviated; follow‐up CT demonstrated shrinkage of the abscess cavity. The clinical course was uneventful. EUS‐guided transgastric drainage could be a safe and effective therapeutic option for IAA secondary to delayed perforation after gastric EMR, particularly when conservative therapy fails and percutaneous drainage is not feasible.