Secondary angiosarcoma is an aggressive tumor that can develop in breast cancer patients treated with conserving therapy and radiotherapy. The symptoms can be misleading, whereas mammography and fine-needle aspiration (FNA) are typically negative in early stage of the disease. A high grade of clinical suspicion is very important for early diagnosis. A case of angiosarcoma involving breast parenchyma in a patient treated with quadrantectomy and radiotherapy for T1cN1Mx breast carcinoma is presented.