Pseudopancreatitis in choledochal cyst in children: intraoperative study of amylase levels in the serum.

A case of acute necrotizing pancreatitis in association with choledochal cyst is presented. Pancreatitis associated with choledochal cyst is probably caused by a biliary reflux into the pancreatic duct via a pancreatobiliary malunion, as the intraductal pressure of the cyst exceeds that of the pancreatic duct. Ampullar stenosis due to gallstones or inflammatory changes may increase the intraductal pressure. Bile with activated pancreatic enzymes refluxes into the pancreatic duct, and possibly results in acute pancreatitis. However, patients with choledochal cyst presenting with recurrent bouts of abdominal pain, vomiting, and fever have often been diagnosed as having acute pancreatitis because of hyperamylasemia, despite no evidence of pancreatitis at the time of surgery. At the time of bouts, they also show a slight elevation of serum bilirubin, and an increase in the degree of the choledochal dilatation that are possibly caused by biliary obstruction, not ampullar obstruction, due to suppurative cholangitis. The term "fictitious pancreatitis" or "pseudopancreatitis" in choledochal cyst appears to be appropriate. This clinical study shows that amylase in the biliary tract has ready access to the blood stream, probably through a sinusoidal pathway by cholangiovenous reflux, and a lymphatic pathway, via the Disse's space and denuded cyst wall, provided the biliary ductal pressure is increased.