Nonmammary malignancies of the breast: ultrasound, CT, and MRI.

The three major categories of nonmammary malignancies of the breast include primary and secondary lymphoreticular malignancy, primary and secondary sarcoma, and hematogenous metastasis. This article describes the imaging features of 35 nonmammary malignancies of the breast and axilla with histopathologic confirmation. These include primary and secondary breast lymphoma, primary axillary nodal lymphoma, metastatic acute lymphatic leukemia, metastatic plasmacytoma, granulocytic sarcoma, primary angiosarcoma, metastatic rhabdomyosarcoma, hematogenous metastasis from primary lung, ovarian, cervical, thyroid, and colonic carcinoma, malignant melanoma, carcinoma of the nasal cavity, and adenocarcinoma of unknown primary. Wherever possible, correlation between mammography and ultrasound, computed tomography (CT), and/or magnetic resonance (MR) imaging is made.