Congenital choledochal dilatation with emphasis on pathophysiology of the biliary tract.

Of 37 patients with congenital choledochal dilatation, aged 8 days to 12 years, who had undergone excision with Roux-en-Y hepaticojejunostomy, 26 patients could be analyzed for morphologic abnormalities and pathophysiology of the biliary tract. Of the 26 patients with congenital choledochal dilatation, 25 (96.2%) had an abnormal choledochopancreaticoductal junction. Of the 12 patients with cystic-type choledochal dilatation, 10 had the C-P type of abnormal choledochopancreaticoductal junction, and of the 13 patients with fusiform-type choledochal dilatation, nine had the P-C type. The amylase levels in the choledochal cyst and the gallbladder were elevated regardless of the form of choledochal dilatation. An adenocarcinoma in a cystic choledochal dilatation was found in one child. Therefore, longstanding inflammation of the biliary tract caused by the reflux of pancreatic juice might be one of the factors in carcinogenesis in the biliary tract. This free reflux of pancreatic juice was demonstrated not only by amylase levels in the biliary tract but also by intraoperative biliary manometry. This reflux might be explained by the lack of sphincter function at the junction of the common bile and pancreatic ducts.