A 69-year-old woman with a history of chronic pancreatitis and gallbladder stone was emergently transported to our hospital for sudden epigastric pain after ingesting alcohol. Her blood test showed elevated pancreatic enzyme levels, including amylase at 3515U/L. Although jaundice was not observed, there was a mild increase in hepatobiliary enzyme levels. Abdominal ultrasonography and computed tomography showed no stone in the common bile duct; however, we observed a fat stranding around the pancreas and made a diagnosis of acute pancreatitis. Although alcoholic pancreatitis was strongly suspected, we performed endoscopic ultrasonography (EUS) to rule out gallstone pancreatitis. On EUS, a 6-mm hyperechoic lesion with acoustic shadow was observed at the papilla; the patient was diagnosed with an impacted stone at the ampulla of Vater. Emergency endoscopic sphincterotomy and removal of the impacted stone were performed. EUS is useful for evaluating biliary obstruction in cases with gallstone pancreatitis and can diagnose impacted stone at the papilla. We strongly recommend EUS in cases with pancreatitis for which an indication of endoscopic retrograde cholangiopancreatography is uncertain.
