Type VI Choledochal Cyst and the Anomalous Pancreaticobiliary Junction: A Systematic Review

ABSTRACT Background: The type VI choledochal cyst of the cystic duct (CC-CD) is not only a taxonomical conundrum but also a matter of research in terms of its etiopathogenesis and optimal therapeutic options. The role of anomalous pancreaticobiliary junction (PBJ) and pancreatic juice regurgitation in the etiopathogenesis of CC-CD and its association with biliary malignancies has not been elucidated yet. Objective: To evaluate the role of anomalous PBJ in the etiopathogenesis of CC-CD and generate a scientific opinion through a systematic review of the literature. Materials and Methods: A literature review (PUBMED, PUBMED Central, PMC, Google Scholar, Google search engine) following the PRISMA guidelines revealed 32 articles of interest. Search terms included choledochal cyst, choledochal, cyst, type VI, type 6, cystic duct dilatation, dilated cystic duct and cystic anomaly. Two independent reviewers extracted the data; the third reviewer had been involved in case of discrepancy. Results: The study-cohort comprised of 45 patients. Roughly, 30% and 60% of the patients were diagnosed in the first and first-two decades of life, respectively. Sex ratio was skewed in favor of females (M:F = 1:1.4). Although males presented earlier than females, females were twice as likely to be diagnosed in the first decade of life. Anomalous PBJ was found in only one-third of these patients and was more common in females. Patients with anomalous PBJ presented early with three-fourth presenting in the first two decades of life. Anomalous PBJ was twice as prevalent in patients with concomitant involvement of other parts of the biliary tract (Group II) as compared to those with isolated CC-CD (Group I). Besides, patients in Group II presented early when compared to Group I, within the group females presented earlier. No significant association of biliary malignancies with anomalous PBJ was seen; the incidence of biliary malignancies was higher in those with a normal PBJ. Conclusions: Observations from the study-cohort fail to establish a strong association of anomalous pancreaticobiliary junction in the etiopathogenesis of CC-CD or the development of biliary malignancies in these patients. It is likely that there are additional or alternative mechanisms that are important in the context of CC-CD.