[Immunohistochemic detection of factor VIII antigen in malignant hemangioendotheliomas of the thyroid. A contribution to histogenesis].

The hemangioendothelioma of the thyroid gland is regarded as a special type of malignant goitre in view of its characteristic morphology and epidemiological behaviour. The histogenetic origin of these tumors (endothelial cells versus a special type of undifferentiated carcinoma of the thyroid) is still unresolved. By an immunoperoxidase method six hemangioendotheliomas were immunocytochemically investigated with an antibody to factor VIII-related antigen, a specific marker for endothelial cells and tumors thereof. In four of these tumors a strongly positive reaction was demonstrated, whereas control sections of undifferentiated and differentiated carcinomas, as well as two hemangioendotheliomas, remained negative. The demonstration of factor VIII-related antigen in four of six hemangioendotheliomas appears to offer evidence that most of these characteristic malignant tumors originate from endothelial cells or endothelial precursor cells. There is a histogenetic difference from true carcinomas originating from thyroid epithelial cells.