Asymptomatic Pneumoperitoneum With a Large Amount of Gas Appeared During Endoscopic Ultrasound-Guided Biliary Drainage.

We report a case in which a large amount of intraperitoneal free gas developed during endoscopic ultrasound-guided biliary drainage with the rendezvous technique. A 62-year-old woman presented with obstructive jaundice caused by a pancreatic head tumor. Endoscopic retrograde cholangiopancreatography was attempted but failed due to difficulty cannulating the bile duct. Consequently, endoscopic ultrasound-guided hepaticogastrostomy was performed using a fully covered metal stent. Subsequently, the rendezvous technique was employed to access the biliary system and perform an endoscopic sphincterotomy. Finally, a fully covered metal stent was placed transpapillary. Fluoroscopic imaging during the procedure revealed a large amount of gas between the liver and diaphragm. Despite the pneumoperitoneum, the patient experienced no abdominal pain or fever. One week later, a computed tomography scan confirmed the disappearance of free air in the intraperitoneal cavity. The patient's subsequent clinical course remained uneventful, and she was discharged from the hospital. This case highlights the potential for pneumoperitoneum to develop during endoscopic ultrasound-guided biliary drainage, particularly when using the rendezvous technique. It is crucial to differentiate this finding from gastrointestinal perforation based on clinical presentation and imaging features.