Congenital stenosis of the intrahepatic bile duct associated with choledochal cysts.

BACKGROUND: There are few studies that report on stenosis of the intrahepatic bile ducts associated with choledochal cysts. We investigated the presence and clinical significance of stenosis of the intrahepatic bile ducts associated with choledochal cysts. STUDY DESIGN: We examined intrahepatic bile ducts in patients with choledochal cysts using cholangiography (93 patients), endoscopy and direct observation during surgery (19 patients), and histologic examination (12 patients). RESULTS: Stenosis of the intrahepatic bile duct was present in 75 (80.6 percent) of 93 patients with choledochal cysts. Endoscopic and direct observation detected membranous stenosis, which consisted of a diaphragm, in 11 of 19 patients. Septal stenosis, which consisted of a bridge-like septum, was present in eight of 19 patients. Stenoses consisted of mucosal and fibromuscular layers. Intrahepatic calculi developed in eight patients with stenosis following resection of the choledochal cysts. CONCLUSIONS: Membranous or septal stenosis of the intrahepatic bile duct is a characteristic feature of choledochal cysts. Our findings suggest that these stenoses should be treated surgically because of the risk of intrahepatic calculi.