Secretory carcinoma of the breast

Secretory carcinoma of the breast is a rare but histologically distinct variant of invasive ductal carcinoma that has an indolent growth pattern and a more favorable prognosis than that of typical ductal carcinoma. We present the imaging and histopathologic findings of a case of this tumor that initially manifested as a palpable mass in the left breast of a 31-year-old woman. It appeared sonographically as a round, well-circumscribed but microlobulated hypoechoic solid mass. Secretory carcinoma of the breast may resemble other well-circumscribed breast carcinomas as well as some benign masses, including fibroadenomas. Breast imagers should be aware of this rare tumor's nonspecific imaging features and clinical implications when making a differential diagnosis of solid breast masses.