Radial Scars Without Atypia Diagnosed at Imaging-Guided Needle Biopsy: How Often Is Associated Malignancy Found at Subsequent Surgical Excision, and Do Mammography and Sonography Predict Which Lesions Are Malignant?

OBJECTIVE. The purposes of our study were to evaluate the surgical outcome of cases of radial scar without atypia diagnosed at imaging-guided percutaneous needle biopsy and to determine whether the mammographic and sonographic features are able to predict which lesions will be upgraded to malignancy at surgical excision. MATERIALS AND METHODS. The records of 4,458 consecutive imaging-guided biopsies were retrospectively reviewed. Surgical excision results were available in 62 cases in which radial scar was the highest-risk lesion at stereotactically guided or sonographically guided biopsy. The mammographic and sonographic images and surgical findings were reviewed. The underestimation rate of malignancy of percutaneous biopsy was calculated. Differences in mammographic and sonographic appearances between radial scars with and without associated malignancy were evaluated using the Fisher's exact test. RESULTS. The percutaneous malignancy underestimation rate was 8% (5/62): 9% (4/43) for sonography guided 14-gauge biopsies and 5% (1/19) for stereotactically guided 11-gauge vacuum-assisted biopsies (p = 1.000). Mammographic and sonographic appearances were not significantly different between radial scars with and those without associated malignancy. CONCLUSION. A percutaneous diagnosis of a radial scar does not exclude associated malignancy at surgical excision. Mammographic and sonographic features of a lesion diagnosed as a radial scar at percutaneous imaging-guided biopsy do not predict which lesions will have associated malignancy at surgery. Therefore, all patients with percutaneous diagnosis of a radial scar should undergo surgical excision regardless of mammographic and sonographic appearances, until further criteria can be determined.