Figure 12a.  T2-weighted fast spin-echo MR image (4,000/100) (a) and contrast-enhanced fast multiplanar spoiled gradient-echo MR image (50/6, 45° flip angle) (b) show a rim-enhancing lobulated mass (arrows) in a 40-year-old woman with a palpable and mammographically visible mass that proved to be medullary carcinoma. Peripheral rim enhancement is strongly associated with malignancy.