Double Extrahepatic Biliary Duct.

We report a 39-year-old male patient diagnosed with double extrahepatic biliary ducts by magnetic resonance cholangiopancreatography. Respiratory-triggered 3-dimensional magnetic resonance cholan - giopancreatography was performed during free breathing. Two extrahepatic biliary ducts, an anomalous union of accessory extrahepatic biliary duct with pancreatic duct, and a unique com - munication channel between 2 extrahepatic biliary ducts were determined on maximum intensity projection and 3-dimensional magnetic resonance cholangiopancreatography volume rendering. This case illustrates the utility of 3-dimensional magnetic resonance cholangiopancreatography for diagnosis of pancreatobiliary ductal system developmental anomalies. Also, we reviewed embryology of the hepatobiliary system and the current classifications of the double extrahepatic biliary ducts and have proposed a new variant of existing classifications.