Eccrine Hidradenoma Mimicking Primary Breast Cancer on Mammography and Ultrasonography

Eccrine hidradenoma is a benign tumor of sweat gland origin that rarely occurs in the breast. It is often mistaken for breast cancer on both clinical and radiological examination. We report the case of a 57-year-old woman with a complex cystic and solid mass in the right breast on ultrasonography that was assessed as breast imaging-reporting and data system (BI-RADS) category 4b. Complete excision yielded a final histopathologic diagnosis of eccrine hidradenoma. Knowledge of radiological findings of eccrine hidradenoma of the breast is important for radiologists to distinguish it from malignancy.