Malignancy rates after surgical excision of discordant breast biopsies

Vacuum-assisted core-needle biopsy (VAB) is increasingly used to perform breast biopsies instead of automated-gun core-needle biopsy (CNB). The significance of discordance between radiologic and pathologic findings has not been well established in the era of VAB predominance. This retrospective study was conducted to determine the rate of malignancy after surgical excisional biopsy (EXB) of these lesions at our two institutions.

We reviewed medical records from January 2008-June 2013 to identify female patients who underwent EXB for a Breast Imaging-Reporting and Data System (BI-RADS) 4 or 5 lesions found to be benign and discordant on CNB. Clinicopathologic data were gathered, and analysis was performed using descriptive statistics.

A total of 8081 core biopsies were performed in the study timeframe. Six of 81 (7.4%) patients who had an EXB for a benign discordant breast lesion were found to have malignant pathology (two invasive, four in situ). Four of 63 (6.3%) lesions originally biopsied by VAB were upgraded, compared with 2 of 17 (11.8%) originally biopsied by CNB. There were no statistically significant differences in the rates of upgrade to malignancy when data were stratified by BI-RADS score or method of biopsy.

The overall rate of malignancy after EXB of benign discordant lesions was 7.4%. Despite the widespread adoption of VAB, EXB is still warranted for clarification of discordant radiologic-pathologic findings.