Imaging-histologic discordance after sonographically guided percutaneous breast biopsy: a prospective observational study.

The objective of this study was to determine the frequency of imaging-histologic discordance and to compare the frequency of carcinoma between concordant and discordant lesions in sonographically (US)-guided 14-gauge core needle biopsies (CNBs). From January 2005 to December 2006, we performed US-guided 14-gauge automated CNB on 3339 breast lesions and obtained benign results in 2194 cases. Five radiologists prospectively reviewed the pathologic reports in conjunction with the imaging. We included a total of 1588 lesions that were either excised (n = 658) or followed up for at least 2 years (n = 930) after CNB. We evaluated the rate of discordance and the clinical findings for both discordant and concordant lesions. We also analyzed the clinical and imaging differences between the upgrade and non-upgrade groups. Imaging-histologic discordance was present in 103 of 1588 (6.5%) lesions. The upgrade rate was 6.8% (7/103) in discordant lesions and 0.4% (6/1485) in concordant lesions (p < 0.01). Lesion size, Breast Imaging, Reporting and Data System (BI-RADS) category and the presence or absence of symptoms was statistically significant between the upgrade and non-upgrade groups in discordant cases (p < .05). Imaging-histologic discordance is an indication for excision because it has a higher upgrade rate than concordant lesions.