INTRAHEPATIC METASTASES IN HEPATOCELLULAR-CARCINOMA - EVIDENCE FOR SPREAD VIA THE PORTAL-VEIN AS AN EFFERENT VESSEL

Background: The mechanism and pathogenesis of the high frequency of in trahepatic metastasis in hepatocellular carcinoma (HCC) has not yet be en elucidated, Methods: Two hundred thirty-one tumors (less than or eq ual to 5 cm in diameter) of resected specimens of HCC were examined fo r the relationship between mode of tumor spread and tumor size, Effere nt vessels in HCC were identified by direct injection of radiopaque ma terial into the tumor in 23 resected liver specimens selected from the 231 tumors. Results: The most frequent site for tumor spread in HCC w as capsular invasion followed by extracapsular invasion, vascular inva sion, and finally intrahepatic metastasis, Radiopaque material injecte d directly into 23 resected tumors entered the portal vein in only 17 tumors and entered into both the portal and hepatic veins in six tumor s, Conclusions: These findings suggest that tumor spread in HCC progre sses from capsular invasion to intrahepatic invasion and that the port al vein may act as an efferent tumor vessel.