The choledocho-pancreatico-ductal junction in infantile obstructive jaundice diseases.

A histopathological study on how the common bile duct and main pancreatic duct open into the duodenum was performed on autopsied cases of infantile obstructive jaundice diseases, and control cases. The so-called "common channel" formation type (Type III) was divided into two types; the junction of the common bile duct and the pancreatic duct was situated in the mucosal or submucosal layer of the duodenum in type IIIa and the junction below the propria muscularis of the duodenum in type IIIb. Type IIIb was identified in 17 out of 28 cases in congenital biliary atresia and in 2 cases of congenital choledochal cyst, while the control cases all belonged to type IIIa. In cases of type IIIb the well-developed sphincter muscle was located in the submucosal layer and it surrounded the common channel after joining of both ducts suggesting the possibility of free communication of both ducts. As the intraductal pressure of pancreatic duct is normally higher than that of the bile duct, reflux of pancreatic juice may occur into the bile duct. Abnormal choledocho-pancreaticoductal junction was suggested to be a pathogenic factor which causes infantile obstructive jaundice diseases. ACTA PATHOL. JPN. 30: 187 approximately 194, 1980.