Anomalous pancreatic duct anatomy, ectopic distal location of the papilla of Vater and congenital biliary dilatation: a new developmental triad?

Background. The opening of the papilla of Vater represents the orifice of the embryonic hepatic diverticulum from which the ventral pancreas, common bile duct, and liver are derived. Recently, we found a strong association between congenital biliary dilatation (CBD), certain types of pancreatic ductal anatomy (PDA), and ectopic distal location of the papilla of Vater which prompted us to study the relationship between the location of the papilla of Vater and abnormal PDA.

Methods. A total of 118 patients with CBD were studied. Cholangiograms documented the presence of pancreaticobiliary malunion (PBMU), the location of the papilla of Vater, and the PDA. Eleven age-matched patients with intermittent jaundice were used as controls.

Results. In the control group, the papilla of Vater was located normally in the descending portion of the duodenum in all cases. In the 118 CBD patients, the papilla of Vater was located normally in 38 (32.2%), but in 80 (67.8%), the papilla was located distal to the descending portion of the duodenum. When the papilla was located distally, the incidences of the specific types of PDA studied were significantly higher than when the papilla was located normally (p<0.01). Pancreatic duct dilatation was also more frequent if the papilla was located distally (28.7%) compared with CBD patients with a normal papilla (7.9%) or normal controls (0%) (both p<0.01). PBMU was present in all CBD patients and absent in all controls.

Conclusion. Our study strongly suggests that abnormalities occurring during early embryological development of the hepatic diverticulum are responsible for the association between abnormal PDA and ectopic distal location of the papilla of Vater in CBD.