CONCEPTS OF THE ETIOLOGY OF CONGENITAL BILIARY DILATATION WITH
SPECIAL REFERENCE TO ECTOPIC DISTAL LOCATION OF THE PAPILLA OF VATER
Long Li
Department of Pediatric Surgery, Juntendo University School of
Medicine, Tokyo, Japan and Department of Pediatric Surgery, Beijing
Children¡¯s Hospital, Beijing, China
The
etiology for choledochal cyst is not unequivocal. In recent years, with the advent of accurate
cholangiographic techniques, attention has been drawn to the close
association of the anomalous arrangement of the pancreaticobiliary malunion
(PBMU), which allows reflux of pancreatic enzymes into the common bile duct
(CBD). However, the chemical
reaction of refluxed pancreatic fluid in the bile duct, was extremely mild, according
to animal experiments in which
choledochopancreaticostomy was performed in puppies.
The
opening of the papilla of Vater represents the orifice of the embryonic
hepatic diverticulum from which the common bile duct, ventral pancreas and
liver are derived. Recently,
we noticed high incidence of abnormal location of the papilla of Vater in
CBD patients which prompted us to investigate whether the abnormal location
of the papilla of Vater is related to the lengths of the common channel and
the common bile duct and whether abnormal outgrowth of the hepatic
diverticulum plays a role in the development of CBD.
It was
found that there was a higher incidence (67.8%) of ectopic distal location
of the papilla of Vater in CBD with pancreaticobiliary malunion than in
controls. The more distal the
location of the papilla of Vater, the longer the common bile duct and the
common channel and the higher incidences of the pancreatic duct dilatation
and variations. These results
suggest that ectopic distal outgrowth of the hepatic diverticulum during
early embryonic development may be an important etiologic factor for CBD.