Abstract
Recently the so-called anomalous arrangement of the pancreatico-biliary duct has often been found in congenital choledochal cyst. This anomaly was also observed in all of our 11 cases in which cholangiograms demonstrated the lower portion of the common bile duct. Therefore, this anomaly has been thought to be responsible for the formation of choledochal cyst by many authors. In order to clarify the etiology of choledochal cyst, we made a model of the anomalous arrangement of the pancreatico-biliary duct in 6 puppies by pancreatico-cholecystostomy. Cystic or spindle-shaped dilatation of the common bile duct was found in all 6 animals. It was proved that digestive effects of proteolytic enzymes in refluxed pancreatic juice on the wall of the biliary duct caused chemical inflammation, which made the structural weakness of the common bile duct and stenosis at its lower portion. Destruction of elastic fibers was principal for the weakness of biliary duct. The wall of biliary duct is likely to be affected by activated pancreatic juice more severely than that of pancreatic duct. Anomalous arrangement of the pancreaticobiliary duct is a most important factor for etiology of congenital choledochal cyst.
