Introduction: Encapsulated peripancreatic fluid collection and walled-off necrosis are some of the complications of acute pancreatitis. Most resolve spontaneously but symptomatic pseudocysts or walled-off necrosis require drainage. The preferred therapeutic management is endoscopic ultrasound (EUS) guided drainage with stent placement. Known iatrogenic complications of the procedure include bleeding and perforation.
Case Description/Methods: A 39-year-old woman with history of ulcerative colitis, in remission on certrolizumab presented with symptomatic walled-off necrosis after idiopathic necrotizing pancreatitis. EUS-guided drainage and stent placement was successfully performed. On subsequent upper endoscopy for necrosectomy, post-procedure large pneumoperitoneum was noted on imaging leading to emergent surgical evaluation with laparoscopy. However, no perforation or pancreatic fluid contamination was seen. On post-operative day 1, patient was asymptomatic and tolerating diet. She was discharged on post-operative day 2. At 3-month follow-up, patient remained asymptomatic and plastic stents were removed.
Discussion: Pneumoperitoneum is an uncommon but dreaded complication of EUS guided cystogastrostomy. This occurs when there is separation of the gastric wall and the wall of the pancreatic cyst or walled-off necrosis. If perforation is detected during cystgastrostomy, it may be possible to use a LAMS to close the defect by bridging the walls or close the gastric defect endoscopically with clips or sutures. Immediate surgery (such as cyst-enterotomy with closure of the wall defect) should be performed if there is generalized contamination of the peritoneum with cyst fluid content and subsequent signs of peritonitis.
Our case, to our knowledge, is the only one that describes pneumoperitoneum after endoscopic necrosectomy, two weeks after placement of LAMS. Our hypothesis is that the walled-off necrosis moved away from the gastric wall after removal of LAMS, which had aided apposition of the gastric wall and cyst wall due to its flanges and short saddle length. Pneumoperitoneum, in the absence of peritoneal findings, is referred to as benign peritoneum. Our case describes massive benign pneumoperitoneum after endoscopic necrosectomy without perforation. There is a paucity of literature on non-surgical management of post-endoscopic pneumoperitoneum and we hope that our case, will help endoscopists carefully select patients who will benefit from surgical management of pneumoperitoneum.
