Immunohistochemistry and angiography in adenomatous hyperplasia and small hepatocellular carcinomas.

The sinusoidal structure and blood supply of 38 liver nodules less than 2 cm in diameter were investigated. There were 18 cases of adenomatous hyperplasia (AH) and 20 cases of hepatocellular carcinoma (HCC). Growth pattern, encapsulation and vascularity were examined, and immunohistochemistry performed for factor VIII related antigen (factor VIII), type IV collagen (collagen IV), laminin and CD68. There were significant differences between AH and small HCC, except for the expression of CD68. There were differences in tumor size, vascularity and the components of the basement membrane between AH and small, well differentiated HCC. The cases of AH were supplied by the portal system and maintained the sinusoidal structure, but small well-differentiated' HCC were supplied by a mixture of portal and arterial vessels. In spite of their small size, moderately and poorly differentiated HCC had capillary and were supplied by branches of the hepatic artery.