We describe 14 cases of angiomatous Kaposi sarcoma (KS), a distinct histological variant of KS first mentioned by Gottlieb and Ackerman in 1988 that can easily be mistaken for a hemangioma. Intriguingly, this variant of KS has not attracted much attention and has not been studied in detail. Immunohistochemistry showed prominent staining of podoplanin (D2-40) of the neoplastic vasculature but not the preexisting vessels, suggesting lymphatic differentiation, despite the erythrocyte-filled round lumens. To test whether D2-40 staining of round vessels with erythrocytes was distinctive, we stained sinusoidal hemangiomas and cellular angiolipomas, both of which have these structures. In contrast to angiomatous KS, the vessels in both entities were podoplanin (D2-40) negative. The finding of round erythrocyte-filled vessels with podoplanin (D2-40) positivity may be distinctive for this form of KS.
*Section of Dermatopathology,
†Department of Pathology,
‡Department of Dermatology, and
§Hellen Diller Comprehensive Cancer Center, University of California, San Francisco, CA.
Reprints: Philip E. LeBoit, MD, Dermatopathology Section, University of California, 1701 Divisadero St, Suite 280, San Francisco, CA 94115 (e-mail: firstname.lastname@example.org).
The authors declare no conflicts of interest.