Osteogenic sarcoma of the breast. A case report.

A case of primary osteogenic sarcoma of the breast is reported. It should be distinguished from carcinoma with extensive osseous metaplasia. The results of light and electron microscopy including an immunohistochemical study are presented. Immunohistochemical and ultrastructural studies proved that the lesion, in the absence of epithelial differentiation, was a primary osteogenic sarcoma of the breast rather than a carcinoma with extensive osseous metaplasia. Diagnosis may be delayed because the tumor is confused clinically and mammographically with a calcific fibroadenoma.