Unexpected anomaly of the common bile duct and pancreatic duct.

Variations in the bile duct and pancreatic duct opening are related to the process of rotation and recanalization during embryologic development. Complete non-union of distal common bile duct and pancreatic duct gives rise to double papillae of Vater. The separation of the drainage of the main pancreatic duct and bile duct can be appreciated by careful assessment at the time of endoscopic retrograde cholangiopancreatograpy. The cranial orifice is a bile duct opening, whereas the caudal orifice is a pancreatic duct opening. The separate orifice finding can be confirmed by cholangiogram and pancreatogram with no communication between the two orifices. Endoscopists should be aware of this rare variant because late recognition can result in unnecessary manipulation and contrast injections of the main pancreatic duct and biliary cannulation failure.