Malignant Endotheliomas With Cutaneous Involvement

The rarity of occurrence, the peculiarities of the clinical course, and the fact that the true nature of the tumor is often concealed because of early surgical or medical interference make a malignant endothelioma peculiarly difficult to distinguish by its clinical characteristics. Because of the difference of opinion regarding the actual existence of endotheliomas, and because of the possibility of serious diagnostic error, illustrated by our own experience, I shall discuss malignant endothelial tumors in the light of three cases which clinically and histopathologically appear to aline themselves with this group. The variability of the endothelial cell in neoplasms and the ability of endothelium to undergo metaplasia, simulating the epithelial type at one point and the connective tissue type at another, has given rise to confusion in the differential diagnosis of endothelial tumors. The controversy with regard to the actual existence of endothelial tumors and the criteria for diagnosis is,