[Case with Todani's type Ib congenital cystic dilatation of the common bile duct].

A 56-year-old man, who had epigastralgia and abnormal liver function test, was admitted to our hospital. ERCP showed common bile duct dilation and stones. We therefore performed endoscopic lithotripsy after endoscopic sphincterotomy. Ten months later, MRCP showed recurrent CBD stones. After rehospitalization, resection of the dilated bile duct was carried out. This case was diagnosed Todani's type Ib congenital cystic dilatation of common bile duct. Todani's type Ib is rare type of congenital dilatation of bile duct, and is interesting embryologically.