A 70-year-old female developed recurrent disease following radiotherapy for primary inoperable breast cancer 5.5 years previously. Salvage mastectomy was performed. Pathology revealed recurrent breast cancer, along with a second primary malignancy, a dermal angiosarcoma. Radical excision of recurrent angiosarcoma failed. Irradiation combined with hyperthermia showed good palliation. The angiosarcoma's possible relation to the initial radiotherapy is discussed.