PURPOSE: To evaluate the prevalence of capsular retraction in malignant hepatic tumors and the factorsinvolved. MATERIALS AND METHODS: Between January 1994 and December 1996, we retrospectively reviewed the CT scansof 152 patients with pathologically-proven, peripherally-located, malignant hepatic tumors. We evaluated size,site, portal and hepatic venous obstruction, bile duct dilatation, and liver atrophy in 18 cases involvingcapsular retraction. RESULTS: The overall prevalence of capsular retraction among malignant hepatic tumors was18/152(12%) ; the prevalence was 9/129(7%) in hepatocellular carcinoma, 6/14(43%) in cholangiocarcinoma and3/9(33%) in metastatic cancer ; among cases of cholangiocarcinoma and metastatic cancer, the prevalence washigh(p <0.05). Portal venous obstruction was seen in six patients with hepatocellular carcinoma (a high incidence ;p=0.041) and one with cholangiocarcinoma. Hepatic venous obstruction was demonstrated in one patient withhepatocellular carcinoma and one with cholangiocarcinoma. Among cholangiocarcinoma patients, bile duct obstructionwas seen in four and liver atrophy in three, but among metastatic cancer cases there were no similar findings. CONCLUSION: The main factors causing capsular retraction were portal venous obstruction in hepatocellularcarcinoma and bile duct obstruction and liver atrophy in cholangiocarcinoma.