Localization of hepatitis B surface antigen in hepatocellular carcinoma

The author respectively examined the localization of hepatitis B surface antigen (HBsAg) in 150 autopsy cases of hepatocellular carcinoma (HCC) with particular attention to growth pattern of HCC. Varying numbers of orcein-positive cells were observed in 42 cases (28.0%) with various distribution patterns, and all the 42 cases were confirmed with immunoperoxidase technique for HBsAg. HBsAg-positive cells were detected in HCC tissue in 10 cases (6.6%) among the 150 cases. Regarding the growth pattern of HCC in the 10 cases, many HBsAg-positive cells were seen in HCCs of the sinusoidal and replacing types, in which the hepatocytes were frequently retained in the cancerous tissue, particularly around the tumor-nontumor boundary. On the other hand, there was no HBsAg-positive cell in the encapsulated type HCC which was the most common (approximately 50%) in the present study and in which the retained hepatocytes were hardly seen. Meticulous histological observation after decoloration of the positive reaction to HBsAg in the sections treated with immunoperoxidase technique and subsequent eosin stain disclosed that HBsAg-positive cells in HCC tissue were retained hepatocytes in 9 cases, and the possibility of HCC cell was not denied in one case. Moreover, HBsAg-positive cells were never detected in tumor thrombi of the portal vein branches and pulmonary metastases.