Figure 5: 70-year-old female with newly diagnosed invasive lobular carcinoma of the left breast. Staging magnetic resonance imaging demonstrated 2 similar-appearing small enhancing masses anterior to the biopsy-proven malignancy. The lesion farthest away was biopsied under magnetic resonance imaging with benign results. It was decided that the 2nd lesion that was closer to the biopsy proven malignancy should be localized for surgery. A two site magnetic resonance imaging guided radioactive seed localization was performed. (a) Axial postcontrast subtraction images demonstrating an enhancing mass (arrow) representing the biopsy proven malignancy. (b) This mass was localized using the nonsubtracted images to better visualize placement of the localization device (arrow). (c) A 2nd suspicious lesion (arrow), 3 cm inferior and slightly anterior to the index malignancy is seen on subtraction images on day of biopsy. (d) The nonsubtraction images were used for the procedure to visualize the localization device (arrow). (e) Coronal postcontrast image with one obturator in the superior mass and one in the inferior mass. Both obturators are in good position (arrows). A radioactive seed was subsequently deployed through each biopsy system. (f) Postprocedure mammogram demonstrating both radioactive seeds in good position (arrows).