Osteogenic sarcoma in the breast--case report of a diagnostic dilemma.

Breast cancer is the leading cancer in females worldwide, the vast majority being carcinomas, and only 0.2-0.3% being sarcomas. Of the mammary sarcomas, extra-osseous osteogenic sarcomas constitute a small heterogeneous group. This communication reports a case of primary extra-osseous osteogenic sarcoma occurring in the breast of a48-year-old female, and presents a literature review of this condition. A pre-requisite for the diagnosis of primary mammary osteogenic sarcoma is the exclusion of an osteogenic sarcoma arising from the underlying ribs or sternum. Like all other osteogenic sarcomas in general, these neoplasms are characterized by the direct formation of osteoid matrix by the tumour cells. Primary osteogenic sarcoma of the breast may arise from metaplastic sarcomatous transformation of neoplastic cells in a primary breast carcinoma, fibroadenoma, malignant phyllodes tumour, or may exceptionally represent a nonphyllodes sarcoma of the breast arising from the soft tissues of an otherwise normal or previously irradiated breast.