Although secondary angiosarcomas (AS) are relatively rare neoplasms, they are increasingly recognized as the result of more breast conserving therapy (BCT) followed by radiotherapy. The diagnosis of this very aggressive and rapidly spreading tumour is based on the immunohystochemical characteristics of the biopsy specimen. Only radical surgical intervention can provide successful treatment. Authors present a case of a 56-y-old woman who underwent BCT and radiotherapy. 10 years later secondary AS occurred in the remaining breast.