Pathomorphological study on thorotrast-induced hepatic angiosarcoma

Pathomorphological study on 18 cases of hepatic angiosarcoma among 93 cases of Thorotrast deposition was carried out. Macroscopically, hepatic angiosarcoma was classified into 4 types: multinodular, massive and diffuse types in addition to mixed type with massive and multinodular. Histologically, hepatic angiosarcoma consisted of 3 main patterns: cavernous, sinusoidal and solid, and they were coexisted in varying degrees in all cases. Factor VIII related antigen was found positive in normal and/or hyperplastic endothelial cells by a peroxidase-antiperoxidase (PAP) method, but negative in neoplastic cells while lysozyme was also negative in neoplastic cells. Varying degrees of hyperplastic changes of endothelial cells were considered as the precursor changes of angiosarcoma, and peliosis was considered as the secondary change. (author)