Pancreatic pseudocyst-portal vein fistula with refractory hepatic pseudocyst: Two cases treated with EUS cyst-gastrostomy and review of the literature.

 Pseudocysts are the most common pancreatic cystic lesions and they usually develop in association with pancreatitis of at least 4 weeks' duration. Extra-pancreatic pseudocysts, although reported, are relatively uncommon. Secondary liver pseudocysts are recognized within the literature, and most patients described have required percutaneous or surgical drainage due to infection or symptoms. The mechanism of hepatic pseudocyst formation is not entirely clear but it is postulated that this phenomenon may occur through pseudocyst-portal vein fistulization. We describe two cases of patients presenting with pancreatic pseudocysts invading the portal venous system with embolization of pancreatic fluid to the liver and subsequent hepatic pseudocyst formation. Interestingly, liver pseudocyst resolution was incomplete with antibiotics and percutaneous drainage alone, and only occurred following endoscopic ultrasonography-guided pancreatic cyst-gastrostomy and metal stent insertion. We have reviewed the current literature on the diagnosis and management of pseudocyst-portal vein fistula formation and we believe that our cases represent the first published within the literature to describe this treatment approach.