Analysis of Morphological Factors of Hepatocellular Carcinoma in 98 Autopsy Cases with Respect to Pulmonary Metastasis

The morphological features of ninety-eight autopsy cases of hepatocellular carcinoma (HCC) were analyzed in relation to pulmonary metastasis. Extrahepatic hematogenous metastasis was observed in 64% and lung was most frequently involved (62%). A close relationship was observed between intrahepatic vascular invasion and extrahepatic hematogenous metastasis to lungs. Portal vein-invasion was found in 80% of cases and significant correlations were recognized between the rates of portal vein-invasion and hepatic vein-invasion, and between the rates of portal vein-invasion and pulmonary metastasis. There was a close correlation among the macroscopic growth-pattern, incidence of vascular invasion, and pulmonary metastasis, and their degrees. Namely, the expansive type HCC showed significantly lower rates of vascular invasion and pulmonary metastasis than the infiltrative or mixed type HCC. These rates were particularly low in the expansive type, single nodular subtype HCC with size of a primary tumor less than 10 cm. Significantly low rates of pulmonary metastasis and portal vein-invasion were also noted in well-differentiated carcinoma (Grade I or II). The existence of cirrhosis or fibrosis of liver in cases with HCC was not definitely related to the occurrence of pulmonary metastasis. It was originally clarified that invasion to the portal vein and the size of HCC played a main role in pulmonary metastasis.