Choledochal cyst in adults: Aetiological considerations to intrahepatic involvement

Background: Choledochal cysts are rare anomalies of the biliary tree and their presentation in adults is infrequent. The high incidence of associated anomalous pancreaticobiliary duct junction (APBDJ) has been well documented. However, the prevalence of APBDJ in different anatomic distribution of cysts has yet to be clarified. Methods: A total 39 adult patients with choledochal cysts were consecutively enrolled: 22 patients had Todani type I cysts, 16 patients had type IVa cysts, and one patient had a type IVb cyst. Results: No statistical differences were found in age, sex or manifestations. A higher frequency of associated APBDJ was identified in patients with type IVa cyst (100%) than those with type I cyst (P < 0.05). With a mean follow-up of 7.2 years after cyst excision, three patients with type I choledochal cyst and four with type IVa cyst have had episodes of recurrent cholangitis, all accompanied with preoperatively diagnosed APBDJ. Conclusion: Anomalous pancreaticobiliary duct junction has a close relationship with adult choledochal cysts, particularly type IVa. We propose the hypothesis that intrahepatic involvement results from progressive enzymatic destruction. Adult choledochal cysts in association with APBDJ, with or without intrahepatic component, should be carefully monitored.