Successful Endoscopic Treatment of Walled‐Off Necrosis With Complex Quadruple Fistulas Among the Necrotic Cavity, Stomach, Duodenum, and Common Bile Duct

We report an extremely rare case of duodenal bulb perforation caused by a double-pigtail plastic stent placed for walled-off necrosis (WON), coexisting with a biliary fistula to the WON and a choledochoduodenal fistula, all successfully managed with endoscopic treatment alone. A 61-year-old woman developed severe gallstone pancreatitis and underwent endoscopic ultrasound-guided transmural drainage for WON with placement of a lumen-apposing metal stent and a double-pigtail plastic stent. After repeated endoscopic necrosectomy, the metal stent was removed and the plastic stent remained in place. Contrast leakage from the WON into the bile duct was detected, and a biliary stent was inadvertently deployed through a choledochoduodenal fistula. Two hundred thirty-seven days after plastic stent placement, endoscopy revealed a duodenal bulb perforation with purulent discharge. The plastic stent was removed, and the gastric fistula was closed using endoscopic hand-suturing. After spontaneous closure of the stent-induced duodenal perforation was confirmed, the biliary stent placed through the choledochoduodenal fistula was removed and a new stent was inserted through the papilla of Vater, resulting in closure of the choledochoduodenal fistula. Complete closure of all fistulas was confirmed 516 days after the initial hospitalization. This case demonstrates that complex fistulas associated with WON can be successfully treated without surgical intervention.