To study the role of anomalous pancreatico-biliary ductal union (APBDU) in the development of choledochal cyst, we reviewed 23 cases. APBDU is defined as a long common channel(>0.4 mm). The patients ages ranged from 1 week to 112 months and the mean age was 22.5 months. Right upper quadrant pain was the most prevalent symptom. The diagnosis was made by ultrasonography and operative cholangiography in most patient. The preoperative diagnosis was made in 100 % of the cases. Gallstones were found in 5 cases. Todani type I and type IV were prevalent. A long common channel was found in all cases. The operative treatment consisted of cyst excision and Reux-en-Y hepaticojejunostomy or choledochojejunosotmy. One patient had postoperative pancreatitis. There was no mortality. We conclude that detection of choledochal cyst is occurring at a younger age and APBDU seems to play an important role in the pathogenesis of type I and IV cysts. Cyst excision is the treatment of choice to eliminate repeated cholangitis and malignant transformation.

The anomalous pancreaticobiliary duct union (APBDU) might cause the formation of choledochal cyst and malignancies of hepatopancreaticobiliary system. The purpose of this study is to make an experimental animal model of APBDU similar to that of human. One to two-month-old Mongrel dogs (n=12) were divided into two groups; the control group (n=2) had a sham operation performed, and in the experimental group (n= 10) the end of distal' common bile duct (CBD) was anastomosed to the side of the dorsal pancreatic duct making APBDD. Serum was obtained for chemical analysis on the 10th postoperative day. The dogs were sacrificed at the 5th week (n=3), the 6th week (n=3), the 7th week (n=2), the 8th week (n=2) and the 6th month (n=2) after the experimental surgery. With sacrifice, operative cholangiogram was taken, and bile juice was obtained for chemistry and bacterial culture. The en-bloc specimens of the hepatopancreaticobiliary system were removed for microscopic examination. Serum and bile juice amylase levels were elevated in the experimental group (n=10), but not in the control group (n=2). Operative cholangiograms of control group revealed no evidence of bile duct dilatation.. On the other hand, the bile duct in the experimental group was markedly dilated without any evidence of stenosis at the anastomosis site (n=10). Histologic examination of the hepatopancreaticobiliary system in the experimental group resembled the findings of choledochal cyst in human. The APBDU of this animal model can produce bile duct dilatation by pancreaticobiliary reflux. We think that this animal model can be potentially promising for the research about the APBDU associated hepatopancreaticobiliary diseases.