The Management of Benign Concordant MRI‐guided Breast Biopsies: Lessons Learned

After benign concordant magnetic resonance imaging (MRI)‐guided breast biopsy, initial follow‐up MRI at 6 months is often recommended for confirmation. This study was undertaken to determine the proper management of stable lesions on initial follow‐up MRI and whether such follow‐up can be safely deferred to 12 months. Retrospective review of 240 MRI‐guided biopsies identified 156 benign concordant lesions. 85 eligible cases received follow‐up MRI and constitute the study population. On initial follow‐up MRI, 72 of 85 lesions appeared adequately sampled, 12 were stable and underwent further MRI follow‐up, and 1 was benign on subsequent surgery. No cancers were diagnosed at the biopsy sites on either 6‐ or 12‐month follow‐up MRI. Among the 12 stable lesions, four were masses and eight were nonmass enhancements. One of the stable masses enlarged on 24‐month follow‐up MRI and proved malignant. All stable nonmass lesions were benign on long‐term follow‐up. After benign concordant MRI‐guided breast biopsy, a stable mass has a 25% probability of malignancy in our series. Re‐biopsy of such masses should be strongly considered. Stable nonmass lesions may be followed with subsequent MRI without rebiopsy. Deferral of initial follow‐up MRI to 12 months may be acceptable.