Figure 4a:

(a, b) US images in a 46-year-old woman with a BI-RADS category 4C lesion in her right breast that was classified as grade 3 invasive ductal cancer at pathologic analysis. At screening US, she also had a 7-mm right breast lesion (arrow in b) and a 7-mm left breast lesion (arrow in a), both of which were classified as BI-RADS category 3; these lesions were not detected at mammography. She elected to undergo bilateral mastectomy (prophylactic on the left side). On the basis of lesion locations, the lesion in the left breast (a) was thought to correlate with DCIS (NX), whereas the lesion in the right breast (b) was thought to correlate with a 10-mm IDC with associated DCIS (N0).