Secretory Carcinoma of the Breast.

Secretory carcinoma of the breast is a rare but histologically distinct neoplasm that generally demonstrates an indolent growth pattern and a favorable prognosis. We present the mammographic, sonographic, and pathologic findings of a case of this tumor which initially presented as a palpable mass. Its appearance on breast ultrasound as a solid, well-circumscribed mass is not specific for this entity and, in fact, mimics benign entities such as fibradenoma, as well as other well-differentiated breast carcinomas. Thus, biopsy is needed for definitive diagnosis of this entity. Since this may initially be performed under imaging guidance, radiologists and clinicians alike need to be aware of this most unusual tumor and its therapeutic and prognostic implications.