A 66 year old man presents with progressive jaundice which he first noticed six week ago. He has a total bilirubin of 22, with 16 direct and 6 indirect, and minimally elevated SGOT. The alkaline phosphatase is about six times the upper limit of normal. He has lost 10 pounds over the past two months, but is otherwise asymptomatic. A sonogram shows dilated intrahepatic ducts, dilated extrahepatic ducts and a very distended, thin walled gallbladder.
