Breast lymphomas only account for approximately 0.15% of malignant breast carcinomas. Half of these are primary lymphomas, and the other half are metastatic to the breast. Ultrasound elastography has been proven to aid in the diagnosis of breast lesions as malignant or benign, with malignancy appearing stiffer compared with normal breast tissue. However, in this study, we review the findings of breast lymphoma on strain and shear wave ultrasonography. Lymphoma appears drastically different on sonoelastography than primary breast cancers, and it could easily be interpreted as benign. Therefore, the unique imaging findings in addition to the patient's clinical history are important in differentiating lymphoma of the breast from other possible diagnoses.

Sonographic elastography has been shown to be a useful imaging modality in characterizing breast lesions as benign or malignant. However, in preliminary research, mastitis has given false-positive findings on both strain and shear wave elastography. In this article, we review the findings in mastitis with and without abscess formation on both strain and shear wave elastography. The elastographic findings in all cases were suggestive of a malignancy according to published thresholds. In cases of mastitis with abscess formation, there is a characteristic appearance, with a central very soft area (abscess cavity) and a very stiff outer rim (edema and inflammation). This appearance should raise the suspicion of mastitis with abscess formation, since these findings are rare in breast cancers.

The incidence of metastases to the breast from nonbreast carcinoma is less than 1% of all breast cancers; of these, adenocarcinoma of the lung to breast is a small proportion (<0.1% of breast carcinomas). The imaging findings of a case of metastatic lung adenocarcinoma to the breast are presented with a review of the literature. Imaging findings including elastography suggesting the breast mass is not a primary breast cancer are highlighted. The importance of notifying the pathologist that nonbreast metastatic disease is in the differential is discussed. The use of appropriate tumor markers is needed; otherwise, the lesion may be interpreted as a triple negative breast cancer.

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