A case of angiosarcoma arising in the setting of transplantation is reported. This rare and malignant tumor of the endothelial system is seldom observed in allograft recipients, with only seven cases having been previously reported. What is interesting about the present observation is that the tumor is thought to have developed in the vicinity of a Dacron graft and that it showed prominent erythrophagocyte-like activity. This activity was associated with a particular clinical syndrome that shared some attributes with infection-associated hemophagocytic syndrome.