Primary metastasizing aortic endothelioma.

An instance of malignant endothelioma, primary in the aorta, metastasizing to intestine and bone, is reported. The aortic tumor was successfully resected. The unexpected finding of a large hepatic growth at autopsy raised the possibility that the aortic neoplasm was a metastasis. Histochemical, immunologic, and ultrastructural studies supported the diagnosis of an endothelial neoplasm. Although a number of malignant aortic and large vessel tumors have been reported, only four previous instances appear to be endotheliomatous.