ERCP, Acute cholecystitis, Gallbladder perforation"/>
The incidence of acute cholecystitis complicating endoscopic retrograde Cholangiopancreatography (ERCP) is rarely reported at 0.2% but is usually associated with a cystic duct obstruction caused by gallstones, gallbladder polyps, or cancer. However, acute cholecystitis with a gallbladder perforation after ERCP without a history of cystic duct obstruction can develop very rarely and has not yet been reported in Korea. We report a case of acute cholecystitis with gallbladder perforation and aggravation of a pancreatic pseudocyst after diagnostic ERCP in a man with a pancreatic cystic lesion. He has been successfully cured using only percutaneous transhepatic gallbladder drainage and antibiotics with no surgery. (Korean J Gastrointest Endosc 2011;42:185-189)