Stewart-Treves syndrome is the development of angiosarcoma in chronically lymphedematous upper extremities following a mastectomy. This is a very rare entity that occurs in 0.07-0.2% of patients treated for breast cancer. The tumor occurs in a median time ranging from 10 to 17 years after mastectomy and is associated with poor prognosis. An aggressive clinical course and metastatic tendency results in a fatal outcome for most patients within two years of diagnosis. The 5-year survival rate does not exceed 15%. A surgical procedure is the treatment of choice. It is generally recommended to perform limb amputation because of the difficulties in macroscopically defining the tumor margins. Radiotherapy and chemotherapy can be of benefit when excision of the primary or recurrent tumor is impossible or when the patient does not consent to the surgical procedure. We present the only case of Stewart-Treves syndrome among 4908 patients treated for breast cancer in our Department from 1977 to 2005.