Malignant Endotheliomas With Cutaneous Involvement

Abstract

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, in part, due to the difficulty of obtaining material from the primary focus at a point where the structure still shows that undoubted endothelial cells gave rise to the tumors. Because of the relatively slow onset and low grade of malignancy of tumors from cells lining blood vessels, lymph vessels, lymph spaces, and serous surfaces, the neoplastic change is usually well advanced before a diagnosis is even attempted. The size of the growth at the time of study makes it practically impossible to trace the various cells through their transition stages to the original proliferating endothelium. This point, among others, is illustrated by the first case 1 of my series. REPORT OF CASES Case 1.-History.-J. C, a man, aged 34, was first examined at the Clinic. April 10, 1921. He had a large ulcer on the left forearm (Fig. 1). His general Thesis submitted to the Faculty of the Graduate School of the University of Minnesota in partial fulfilment of the requirements for the degree of Master of Science in Dermatology and Syphilology, April, 1922. 1. This case was presented for diagnosis by the Section on Dermatology and Syphilology of the Mayo Clinic before the joint meeting of the Minnesota. Chicago and St. Louis Dermatological Societies at Rochester, Minn. August, 1921.