A malignant tumour originating inside the endothelium.
Any tumor arising from or resembling endothelium. It may arise from the linings of blood or lymph vessels (hemangioendothelioma and lymphan-gioendothelioma respectively); from the linings of the pleural or peritoneal cavities; or from the meninges (see meningioma).
A malignant growth of lining cells of the blood vessels.
A growth or tumor originating from endothelial cells.