Studies on Formation of Bile Duct Stones Due to Congenital Malformation of the Biliary Tract

Part I Clinicopathological Classification of Congenital Cystic Dilatation of the Common Bile Duct

Abstract

Forty-six patients with congenital dilatation of the common bile duct were studied. As the typical form of this disease, a succular dilatation of the common bile duct and narrowing of the terminal bile duct below the dilatation were seen and the microscopic findings of thedilated wall showed the absence of the subserous muscle layer.
Cystic dilatations (Alonso-Lej's Type I) were most common. We classified congenital cystic dilatation (Alonso-Lej's Type I) into two subtypes, infant type and adult type, on the basis of morphological and clinical findings.
The patients, whose common bile duct and/or common hepatic duct were affected by the enlargement, had the typical cyst combined with the remarkable narrow segment of terminal bile duct. These were encountered in children. On the other hand, the patients whose whole extrahepatic bile duct and/or the main branches of intrahepatic bile duct were affected, had the fusiform cyst or cylindrical cyst, and most of them had floating stones in the cyst. These were most common in adults. It is reasonable that the formers are called"infant type"and the latters are"adult type".