Imaging Features of Adult Choledochal Cysts: a Pictorial Review

Choledochal cysts are rare congenital anomalies which are principally diag-nosed by disproportional dilatation of the extrahepatic bile ducts. In addition, choledochal cysts are believed to arise from the anomalous union of the common bile duct and pancreatic duct outside the duodenal wall which is also proximal to the sphincter of the Oddi mechanism. The various types of choledochal cysts have been classified on the basis of these anomalous unions (Komi classifica-tion) and their anatomical locations (Todani classification). The multidetector computed tomography with reformatted imaging, magnetic resonance cholan-giopancreatography, and an endoscopic retrograde cholangiography represent the important techniques providing the anatomical resolution and detail required to properly diagnose and classify choledochal cysts and their associated abnor-mal features of the biliary tree, as well as their pancreaticobile duct union. This study describes the various imaging features of a choledochal cyst in adults according to the various types of anomalous unions of the pancreaticobile duct according to Komi’s classification and anatomic location according to Todani’s classification. Lastly, we also review and discuss the associated abnormal find-ings developed in biliary systems. holedochal cysts are congenital cystic dilatations of any portion of the bile ducts, but most often occur in the main portion of the common bile duct (CBD). The diagnosis of a choledochal cyst is made on the basis of disproportional dilatation of the extrahepatic bile ducts (EHDs) after excluding the possibility of a tumor, stone, or inflammation as the cause of the dilatation. The estimated incidence of choledochal cysts in Western countries varies between 1 in 100,000 and 1 in 150,000 individuals. The rate of incidence is higher in Asia and occurs more frequently in women (1 male: 4 female) (1). Though the diagnosis of a choledochal cyst is most often made during childhood, 25 % of patients are initially seen as adults (2). Abdominal pain, jaundice, and an abdominal mass are noted in most child cases. Although abdominal pain is the most common presenting symptom in adult cases (1, 3), most had nonspecific clinical symptoms (4). Further, secondary hepatobiliary disease in adults may obscure the primary condition