[Clinical and experimental studies on the etiology of congenital biliary dilatation (CBD)--with special reference to relationship between elastic fibers in the wall of the bile duct and type of CBD].

: The purposes of this study are to clarify the correlation between the morphological differences in congenital biliary dilatation (CBD) and elastic fibers in the wall of the bile duct. Using forty-three patients with CBD and fifty-seven autopsy cases in which history of biliary disease had not demonstrated, histopathological studies have been performed. In addition, experimental models of anomalous choledocho-pancreatico ductal junction were created in twenty-two young sheep and nine neonatal lambs, and the differences in morphological change were studied in two groups. The results are as follows. 1) Elastic fibers were not seen in the wall of the common bile duct of neonate or infant. So it suggests that the ductal wall was extremely weak in this period and increased intraluminal pressure of the biliary system, induced by distal obstruction, caused the cystic dilatation easily. 2) Fusiform dilatation of the extrahepatic bile duct was produced in all experimental models. The reason why cystic dilatation was not caused in these models is that elastic fibers were abundant in just ductal wall of neonatal lambs. From these results, aging factors may play an important role in the formation of CBD.