Analysis of false-negative findings of breast cancer on previous magnetic resonance imaging

Background Despite the excellent contribution of contrast-enhanced breast magnetic resonance imaging (MRI), there are variable false-negative cases on MRI. Purpose To evaluate the false-negative findings of breast cancer on previous MRI. Material and Methods Between 2012 and 2016, we collected 132 patients who underwent surgery for a second primary cancer and had both current and previous MRI at an interval of <3 years. We included 45 patients; we excluded 38 patients who could not find a second cancer in the previous MRI and 49 patients who had a second cancer near to the original cancer and within within the same quadrant. Compared with current MRI, we retrospectively assessed the second primary cancer on previous MRI according to BI-RADS and analyzed the reasons of misinterpretation. Results Analysis of previous MRI revealed 26 (57.8%) masses (mean size 7.7 +/- 2.25 mm), 12 (26.7%) non-mass enhancements (mean size 14.7 +/- 4.76 mm), and 7 (15.5%) foci. At first reading, 24 (53.3%) were missed, 17 (37.8%) were assessed as BI-RADS category 2 or 3, and 4 (8.9%) were assessed as category 4. On current MRI, 39 (86.7%) lesions showed an increase in size and 22 (48.9%) showed a change in kinetics to wash-out pattern. Conclusion On previous MRI, missed or misinterpreted cancers show variable findings of mass and non-mass enhancements with any types of kinetics. Careful application of BI-RADS is necessary as well as an appropriate biopsy. Any lesion that increases in size and changes in kinetics should not be underestimated.