Abstract
Fibroadenomas are among the most common benign breast tumors in which carcinomas rarely develop. We report the imaging findings of a microinvasive ductal carcinoma arising within a fibroadenoma in a 51-year-old woman. This mass showed coarse heterogeneous microcalcifications within a circumscribed mass on mammography, a heterogeneous hypoechoic mass on ultrasound, and an early enhancing mass on magnetic resonance imaging. Although a fibroadenoma in an older woman appears benign-looking, the presence of any unusual signs should raise concerns about malignancy.