Computed tomographic and ultrasonic appearances of primary carcinoma of the common bile duct.

Two patients with obstructive jaundice due to surgically proved primary carcinoma of the common bile duct were examined by CT and ultrasound. The combination of the two modalities showed dilatation of the extrahepatic biliary system and the main pancreatic duct. The diagnosis of primary bile duct carcinoma is suggested by these findings in the presence of a normal pancreatic head, although similar findings may occur with a small pancreatic or ampullary carcinoma.