Juan Manuel Pazos Guarín
Primary osteosarcomas of the breast are very rare neoplasias, accounting for less than 1% of breast carcinomas and 12.5% of breast sarcomas, with only 50 cases reported in the last 50 years. The mechanism of tumorigenesis is not clear, it’s postulated that it is formed from totipotential cells of the stroma. It´s also has been postulated that previous radiotherapy may induce formation of breast sarcoma like ostegenic sarcomas. We report a case of a 93 year old female with a history of left mucinous breast cancer treated with adjuvant chemotherapy and radiotherapy and breast conserving surgery. Five years later, another tumor emerged in the left breast which was diagnosed like osteosarcoma. This case study traces that osteosarcoma of the breast may occur in a patient with previous radiotherapy.