INTRAHEPATIC METASTASES IN HEPATOCELLULAR-CARCINOMA - THE ROLE OF THEPORTAL-VEIN AS AN EFFERENT VESSEL

The mechanism and pathogenesis of the high frequency of intrahepatic m etastasis in hepatocellular carcinoma (HCC) has not yet been elucidate d. Two hundred and thirty one tumors (less than or equal to 5 cm in di ameter) of resected specimens of HCC were examined for the relationshi p between mode of tumor spread and tumor size, Efferent vessels in HCC were identified by direct injection of radiopaque material into the t amer in 23 resected liver specimens selected at random from the 231 tu mors. The most frequent site For tumor spread in HCC was capsular inva sion followed by extracapsular invasion, vascular invasion, and finall y intrahepatic metastasis. There was a strong statistical correlation between the presence of intrahepatic metastasis and the frequency of v ascular invasion (correlation coefficient=0.998). Radiopaque material injected directly into 23 resected tumors entered only the portal vein in 17 tumors and into both the portal and hepatic veins in six tumors . In all eight patients with unresectable lesions, radiopaque media in jected percutaneously into turner nodules hewed only into the portal v ein. These findings suggest that tumor spread in HCC progresses from c apsular invasion to intrahepatic invasion and that the portal vein may act as an efferent turner vessel.