Angiosarcoma following MammoSite partial breast irradiation

Angiosarcoma is a rare tumor of endothelial origin which commonly arises in small blood or lymphatic vessels. Its development in the treated breast following adjuvant external beam radiation is also rare. To our knowledge, there are no reported cases in the literature or MammoSite registry which describe the occurrence of angiosarcoma in the treated breast following MammoSite brachytherapy. This is a case report of a 74 year old female who developed angiosarcoma 4 years after receiving MammoSite balloon brachytherapy following surgical resection of a T1mic N0 M0 infiltrating ductal carcinoma.