Twenty-eight cases of hepatocellular carcinoma(HCC)involving bile duct and causing obstructive jaudice in this hospital between 1987-1994 were studied.In this series cancerous cast formation in bile duct was found in 13 cases and cancerous thrombus in 15 cases which accounts for 5.7% of 487 HCC patients admitted to this hospital in the same period.According to the operative and pathological findings,characteristics of cancerous cast type are:①direct connection of cancerous cast with the primary tumor as a dumb bell-shped,②no adhesion between the cast and the thin wall of bile duct,③central location of the primary tumor in liver near the larger bile duct and ④HCC tissues seen in pathologic section of the cast.Characteristics of cancerous thrombus type are:①no connection between intraductal thrombus and the primary tumor,②segmental stenosis or obstruction of the bile duct,③adherence of cancerous thrombus to the thick ductal wall,④peripheral location of the primary tumor and⑤HCC cells scattered in the thrombus.