We present a case of chronic lymphoedema that progressed to Stewart-Treves syndrome in a 63-year-old woman with a previous modified radical mastectomy, associated lymph node dissection, chemotherapy and radiotherapy. While producing stabilisation of most cutaneous lesions initially, chemotherapeutic treatment of the angiosarcoma did not prevent subsequent metastasis and patient death. We urge vigilance and regular follow-up appointments for patients following a mastectomy with chronic lymphoedema to facilitate prevention or early treatment of this devastating syndrome.