Primary osteosarcoma of breast, a rare case.

Mammary sarcomas are very uncommon and make up less than 1% of all primary breast malignancies.Primary osteosarcoma of the breast is extremely rare and represents 12.5% of mammary sarcomas. A secondary lesion from a primary osteosarcoma of the bone should be considered in the differential diagnosis. In addition, the absence of a direct connection between the tumour and the underlying skeleton is mandatory for the diagnosis.We report a case of primary osteosarcoma of the breast occurring in young patient with fatal evolution.