Endoscopic ultrasound-guided drainage of a subcapsular hepatic pancreatic pseudocyst: a novel application of a lumen-apposing metal stent with visualization of fluid communication pathways.

Background and Aims: Subcapsular hepatic pancreatic pseudocysts (SHPCs) are rare adverse events of pancreatitis. Traditional management involves percutaneous or surgical drainage, but endoscopic ultrasound (EUS)-guided approaches are underexplored. To our knowledge, we report the second documented case of EUS-guided SHPC drainage and the first using a lumen-apposing metal stent (LAMS), highlighting EUS's therapeutic role. Methods: A 44-year-old man with alcohol-induced necrotizing pancreatitis presented with persistent pain and a developing biconvex subcapsular hepatic fluid collection on computed tomography (CT). EUS identified the SHPC and revealed a breach in the liver capsule with fluid tracking along the gastric fundus, spleen, and peripancreatic spaces, likely via the gastrosplenic or left coronary ligament. These findings guided LAMS placement into an adjacent communicating extrahepatic collection, avoiding direct hepatic access. Results: LAMS placement achieved successful drainage, confirmed by CT showing near-complete resolution at 7 days. Double-pigtail stents replaced the LAMS to maintain internal drainage for 8 months. A subsequent infected peripancreatic pseudocyst was managed with an additional LAMS and antibiotics. On follow-up at 10 months, all collections had resolved, and the patient remained well. Conclusions: This case highlights EUS-guided LAMS drainage as a promising minimally invasive SHPC treatment alternative. EUS's ability to delineate fluid communication pathways enhances therapeutic precision.