Relationship between Anomalous Pancreaticobiliary Ductal Union and Pathologic Inflammation of Bile Duct in Choledochal Cyst

Purpose: Choledochal cyst is a cystic dilatation of common bile duct. Although the etiology is presently uncertain, anomalous pancreaticobiliary ductal union (APBDU) is thought to be a major etiology of choledochal cyst. In this study, we analyzed the clinical and anatomical characteristics and pathologies of patients diagnosed with choledochal cyst in a single institute for 25 years. Methods: A total of 113 patients, diagnosed with choledochal cyst and who received an operation in Severance Children's Hospital from January 1988 to May 2013, were included. Medical records were reviewed, including clinical and demographic data, surgical procedures. Abdominal ultrasonography, magnetic resonance cholangiopancreatography, and intraoperative cholangiography were used as diagnostic tools for evaluation and classification of choledochal cyst and the presence of anomalous pancreaticobiliary ductal union. Todani's classification, and relationship between APBDU and surgical pathology. Results: Among 113 patients, 77 patients (68.1%) presented symptoms such as hepatitis, pancreatitis and/or cholecystitis. Eighty three patients (73.5%) had APBDU, and 94 patients (83.2%) showed inflammatory pathologic changes. APBDU, pathologic inflammation, and serological abnormalities such as hepatitis or pancreatitis showed a statistically significant correlation to one another. Conclusion: APBDU is thought to be one of the etiologic factors of choledochal cyst. It is related to the inflammatory changes in bile duct that can lead to the cystic dilatation.