(a)
(b)
Figure 4: 41-year-old woman presenting for screening. Mammography (not shown) demonstrated heterogeneously dense breast with no suspicious abnormality. (a) Screening ultrasound shows a hypoechoic mass with irregular shape and margin. The patient was lost to follow-up after the biopsy. (b) Dense fibrous stroma with small capillaries (arrows) and adjacent appearing lobular units.