Case 186. Reference case 186A

　 　 　 　
　 Immunostaining for factor VIII-related antigen (von Willebrand factor), demonstrating positivity in the tumor cells. 　
　 　 　 　

　

 　 Most of the proliferating cells express the endothelial marker, confirming the endothelial origin of the tumor cells. Multifocal and multiorgan involvement of Kaposi sarcoma was seen at autopsy.