The presence of a positive pressure gradient from pancreatic duct to choledochal cyst demonstrated by duodenoscopic microtransducer manometry: clue to pancreaticobiliary reflux.

A case of choledochal cyst is presented. The diagnosis was established by endoscopic retrograde cholangiopancreatography, which also demonstrated that the common bile duct joined the pancreatic duct at an abnormally long distance from the papilla. Duodenoscopic manometry using a microtransducer catheter showed that the pressure in the pancreatic duct was higher than that in the choledochal cyst by 1.1 mmHg. The cyst-to-duodenum pressure gradient of 3.5 mmHg was not different from the common duct-to-duodenum gradient in patients with other common biliary tract diseases, making the presence of a stenosis as an etiology of this entity unlikely. The bile aspirated from the gallbladder had an extremely high amylase content, suggesting influx of the pancreatic juice into the biliary system. The pancreaticobiliary reflux caused by the positive pressure gradient from the pancreatic duct to the choledochal cyst may be related to the development of the disease.