Subjects will undergo EUS and/or ERCP as outpatients. For cysts shown to communicate with the main pancreas duct, a balloon catheter will be placed in the main pancreatic duct via ERCP. The balloon catheter will isolate the cyst from the main pancreatic duct, allowing ethanol injections of the cyst. A pancreatic duct stent will be placed in some patients, requiring repeat endoscopy for removal at another time.