Transmesocolic Cystojejunoanastomosis in a Mexican Patient With a Giant Post-acute Pancreatic Pseudocyst Following Acute Pancreatitis: A Case Report.

Giant pancreatic pseudocysts (GPPCs) are a rare but challenging condition, particularly when they reach a size that compromises the surrounding anatomy and the available therapeutic resources. Here, we present the case of a 45-year-old man with a history of severe acute pancreatitis who developed a 5.5-litre cystic collection located in the right hepatorenal space, extending into the infrahepatic retrocolic compartment and displacing the duodenum. This caused significant gastric displacement, progressive abdominal pain, and oral intolerance. Due to the unavailability of endoscopic ultrasound (EUS) and the anatomical unsuitability for cystogastrostomy, caused by marked stomach displacement and lack of safe access, an open surgical approach involving Roux-en-Y (RY) cystojejunoanastomosis via the transmesocolic route was selected. This approach enabled effective dependent drainage without postoperative complications, resulting in a favourable clinical and radiological outcome at one year. This report illustrates the necessity of individualised surgical planning in cases of GPPCs with complex topography. It also underscores the value of transmesocolic cystojejunoanastomosis as a reliable strategy in high-complexity abdominal scenarios where conventional endoscopic options are unavailable or contraindicated.