Selected case from the Arkadi M. Rywlin international pathology slide seminar: Injection-site high-grade angiosarcoma, subcutis, Left Buttock Region

A high-grade angiosarcoma with epithelioid features located in the buttock of an 87-year-old woman arose in an area of old, palpable fat necrosis at the site of several subcutaneous injections administered 20 years previously. The nature of the injected material is unknown, but is presumed to have been an iron compound. Two weeks before surgery, the buttock lesion started to enlarge and was excised. It consisted of 3 contiguous nodules of old, calcified fat necrosis associated with plentiful hemosiderin. One of the nodules was largely replaced by an angiosarcoma, which was invading the edges of the other 2 nodules. The patient died from wound sepsis 41 days postoperatively, with no clinically apparent metastases. Vaccination injection-site sarcomas are well known to occur in cats, whereas in humans, rare sarcomas associated with prostheses and foreign materials have been reported; however, human injection-site sarcomas are vanishingly rare. The Club members agreed with the diagnosis of angiosarcoma at an injection site, with the majority calling it an epithelioid angiosarcoma. Many accepted that the injected material was probably iron, but one cautioned about regarding the injections as the cause of the angiosarcoma.