ABSTRACT
The primary osteosarcoma of the breast is a rare tumor representing only 0.25% of malignant breast tumors. Its diagnosis is based on the exclusive presence in the breast of an ostrogenic sarcomatous component, and the absence of any epithelial component confirmed by immunohistochemical and ultra-structural study. For localized stages, the treatment is mainly based on surgery. The place of adjuvant treatments [radiotherapy and chemotherapy] remains to be defined. For metastatic palliative chemotherapy is recommended. A woman of 45 years old, without particular pathological history, presenting a primary osteosarcoma of the left breast, confirmed by immunohistochemical study and a correct staging, metastatic from the outset, treated by a palliative chemotherapy with a fatal outcome. We will discuss the risk factors for primary breast osteosarcoma of diagnostic, its diagnostic criteria treatment and outcome, with a review of the literature. We will discuss also its histological aspects, treatment and outcome, with a review of the literature It is an aggressive disease that requires early diagnosis, adequate and early therapeutic management to ensure good locoregional and general control and improve better outcome. His prognosis is still very pejorative