Benign conditions of the intrahepatic or extrahepatic bile ducts can range from focal or diffuse dilatations (choledochal cyst) to obstructive strictures of the biliary tree. Historically, choledochal cyst disease was considered a disease of childhood but is increasingly being recognized in adults. In the United States, benign biliary strictures most commonly occur as a result of injury after cholecystectomy but also occur in a number of diverse inflammatory conditions affecting the biliary tree. Both conditions represent significant clinical challenges where proper evaluation and management are paramount to prevent serious clinical sequelae.
Choledochal cysts are focal or diffuse dilatations of the biliary tree, and aside from biliary atresia, they are the most common congenital abnormality of the biliary tree. Choledochal cysts can occur as single or multiple cysts throughout the extrahepatic or intrahepatic bile ducts. The cysts can predispose patients to recurrent cholangitis or pancreatitis, choledocholithiasis, secondary biliary cirrhosis, biliary stricture, and malignancy.
The incidence of choledochal cysts varies significantly throughout the world. Choledochal cysts appear to be most common in Asian countries with an estimated incidence of 1 in 13,500; the incidence has been reported to be as high as 1 in 1000 in studies from Japan. In Western countries, choledochal cysts occur much less frequently, with reported rates that vary from 1 in 150,000 to 1 in 2 million live births.1 Biliary cysts are 4 times more common in women compared with men. Approximately 80% of choledochal cysts are diagnosed in children, and 20% of cases present in adults.2 There are a few case reports of choledochal cysts occurring within families, but generally, they do not have a recognized hereditary pattern.
The anatomy of choledochal cyst disease was first described by Vater in 1723, and in 1959, Alonso-Lej categorized 3 types of choledochal cysts.3 The classification system was revised by Todani and colleagues in 1977 to the 5 cyst categories4 that are in use today (Table 64-1). A similar classification has been proposed based on bile duct cholangiographic appearance.5,6
TABLE 64-1ALONSO-LEJ/TODANI MODIFICATION OF THE CLASSIFICATION OF CHOLEDOCHAL CYSTS ||Download (.pdf) TABLE 64-1 ALONSO-LEJ/TODANI MODIFICATION OF THE CLASSIFICATION OF CHOLEDOCHAL CYSTS
|Type I ||Classic cyst type characterized by cystic dilatation of the common bile duct; most common, comprising 50%-80% of all biliary cysts; subdivided into IA (cystic), IB (fusiform), and IC (saccular) |
|Mixed type I and II ||Fusiform dilation of the extrahepatic biliary tree in combination with a separate diverticulum, midportion of the common bile duct, with cystic duct entering in the right of the diverticulum, comprising 1% |
|Type II ||Simple diverticulum of the extrahepatic biliary tree, comprising 2%-3% of all cysts; located proximal to the duodenum |
|Type III ||Cystic dilatation of the intraduodenal portion of the extrahepatic common ...|