A supplementary screening US detected cancer case in a 40-year-old woman that was initially assessed as BI-RADS category 3 (case 8 in Table 2). Initial supplementary screening US was assessed as BI-RADS 3 due to multiple small oval isoechoic nodules in both breasts. Diagnostic US after 6 months revealed that the mass in right breast increased in size up to 1.1 cm, and it was still not palpable. Both initial and follow-up mammograms were negative (not shown here). The pathologic diagnosis was invasive ductal cancer. US, ultrasound; BI-RADS, Breast Imaging Reporting and Data System.