Primary osteosarcoma of the breast.

We report a case of primary osteosarcoma of the breast, which is a rare histological type of all breast tumors. A 58-year-old woman had noticed a right breast mass long before presenting to our hospital because it had gradually increased in size. The mass was bony-hard, 90 x 70 mm in size, and was located mainly in the upper outer quadrant of the left breast.