Abstract
To clarify the difference between multicentric occurrence (MC) and intrahepatic metastasis (IM), the ratio of the occupying area of histologic differentiation grades (HDG) and histological progression in 38 nod-ules of solitary hepatocellular carcinoma (HCC), and in the largest and in the next to largest nodule of 24 cases of multiple HCC, were investigated among surgical cases of small HCC in which the main tumor was smaller than 30mm in diameter. The next to largest nodules in multiple cases in which well-differentiated (-diff) HCC was found were classified as MC group (9 cases), in multiple cases in which well-diff HCC was absent were classified as IM group (15 cases). The area-ratio of HDG and the degree of the tumor histological progression of the largest nodules in MC group were similar to those of solitary HCC nodules. However, the largest nod-ules in IM group showed a high area-ratio of moderately-and poorly-diff HCC, and a high positive rate of fc-inf and vp. No difference was observed between the groups in location of nodules in the liver, or in the difference in diameter between the largest and the next to largest nodules, however the next to largest nodules in IM group showed a high positive rate of tumor staining on DSA angiography. It was concluded that in differenti-ating IM from MC for multiple small HCCs existence of well-diff carcinoma in the next to largest nodules should be examined.
