Breast metastases from extramammary malignancies.

Metastatic foci to the breast from a wide variety of primary malignancies appear on mammograms as circumscribed spheroid shadows with only slightly irregular margins, and without evidence of microcalcifications, spiculations, or other signs of desmoplastic response that characterize many primary scirrhous carcinomas. In the cases studied, there was close correlation between the size of the metastatic lesion at palpation and mammography, a feature also characteristic of the well-circumscribed carcinomas. This is not the case with most scirrhous breast carcinomas, whose associated desmoplastic reaction results in an apparent larger size by palpation than observed on mammography.