Proliferative activity in intrahepatic metastasis of hepatocellular carcinoma

To assess the characteristics of intrahepatic metastatic lesions (IML) in hepatocellular carcinoma (HCC), we analysed both the histological features and proliferative activities of 15 resected cases of HCC accompanied by IML. The histological features of the IML were essentially the same as those observed in the main nodules in 12 (80%) of 15 cases. In 13 (87%) of 15 cases, the labelling index of proliferating cell nuclear antigen (PCNA) in the IML was either higher than or the same as in the main nodules. In 10 (77%) of 13 cases, the MIB-1 labelling index in the IML was either higher than or the same as in the main nodules. The results indicate that the histological features of the IML are essentially the same as those of the main nodules, while the proliferative activities in the IML were generally higher than those in the main nodules. Such characteristics may thus provide a clue to help distinguish intrahepatic metastasis from the multicentric occurrence of HCC.