In 1948 Stewart and Treeves recognised and described six cases of lymphangiosarcoma arising in the oedematous upper limb of patients who had previously undergone radical mastectomy and radiotherapy for breast carcinoma. The incidence of lymphangiosarcoma in such patients is 0.45% and is uniformly aggressive and fatal, with a 5-year survival of less than 5% regardless of the treatment modality. We present a case report to increase the clinical awareness of this rare and fatal iatrogenic complication occurring subsequent to breast cancer treatment, and speculate on ways of improving survival.