Histopathologic studies of congenital dilatation of the bile duct as related to an anomalous junction of the pancreaticobiliary ductal system: clinical and experimental studies.

Clinical and experimental studies of congenital dilatation of the bile duct as related to an anomalous junction of the pancreaticobiliary ductal system were performed. Epithelial hyperplasia accompanied by round cell infiltration and increased thickness of the wall with fibrosis was observed histologically in the resected bile ducts of all 40 patients. Twenty-two of 26 patients (86.4%) who had bouts of abdominal pain showed that epithelial hyperplasia with round cell infiltration is dominant (glandular type), and 11 of 15 cases (73.7%) with persistent jaundice showed that thickness of the wall with fibrosis is dominant (fibrotic type). Amylase activities in bile of glandular-type cases obtained from the common bile duct intraoperatively were significantly greater than those of fibrotic-type cases (p less than 0.01). The common bile ducts of the canine model, in which whole pancreatic juice passed in the bile duct, dilated cylindrically 3.28 +/- 2.48 times in diameter after 24 to 41 days and histologically showed epithelial hyperplasia with round cell infiltration of the glandular type. These findings suggest that an anomalous junction of the pancreaticobiliary ductal system and the reflux of pancreatic juice into the bile duct affect not only clinical manifestations but also pathologic changes, especially of the glandular type, in patients with congenital dilatation of the bile duct.