Angiosarcoma is a rare, aggressive, malignant tumor that arises mainly on the face and scalp in elderly persons. It can be associated with lymphedema, vascular stasis, and irradiation. There are also angiosarcomas that occur in soft tissues and in visceral organs after exposure to chemicals (arsenicals, vinyl chloride, and thorium). Some tumors are reported to arise in preexisting benign tumors, such as hemangioma, neurofibroma, intramuscular lipoma, and leiomyoma, or in association with retained foreign material or gouty tophus.1 The term Stewart-Treves syndrome is used only for an angiosarcoma that occurs in the context of long-standing lymphedema. Classically, this condition arises in the arm of a female patient 1 to 30 years after mastectomy with axillary lymph node dissection, with or without radiation therapy. More rarely, it can occur in other types of chronic lymphedema, including congenital or iatrogenic forms, or lymphatic malformations.