Primary breast sarcomas represent less than 1 % of all malignant breast neoplasias. The principal risk factor for these fast growing lesions is previous radiotherapy treatment. We present a case of a 55 year-old woman with a 4,5 cm tumour, which was diagnosed as a chondrosarcoma after excluding other possibilities, such as metaplastic carcinoma, malignant phyllodes tumour, stromal sarcoma (spindle cell) and osteosarcoma. Very few cases of this rare tumour have been reported in the literature.