Biliary Tract Anomalies

• Unknown etiology.
   
• Anomalous junction of common biliary duct and pancreatic duct. Examples are shown in diagram below:

• A long common channel may cause:
   
• Reflux of pancreatic secretions into bile ducts.
   
• Repeated reflux of pancreatic secretions leads to weakening of the bile duct wall.
   
• This process is believed to be related to the formation of choledochal cysts.