False-negative ultrasound-guided vacuum-assisted biopsy of the breast: difference with US-detected and MRI-detected lesions.

Background: The purpose of this study was to retrospectively examine the frequency and causes of a false-negative result of ultrasound (US)-guided vacuum-assisted biopsy.

Methods: A retrospective review was performed of 835 patients with 986 consecutive lesions who had undergone US-guided vacuum-assisted biopsy (US-VAB) using 11-gauge probes. We divided the lesions into two groups (US-detected and MRI-detected lesions). The sizes of the lesions on US, number of cores taken, rates of repeat biopsy, and the false-negative rate were compared between the two groups.

Results: The overall false-negative rate of US-VAB was 7.4% (13/175). The final number of malignant pathologic diagnoses was 175 (18%), including 13 false-negative lesions and 6 upgraded high-risk lesions. The false-negative rate for MRI-detected lesions (26%; 8/31) was significantly higher than that for US-detected lesions (3.5%; 5/144) (P = 0.0002). The causes of a false-negative result in the case of US-detected lesions were considered to be technical error in two cases and difficulty in histologic interpretation in three cases. The average size, as measured by US, average number of core samples, and repeat biopsy rate of US-detected lesions and MRI-detected lesions were 11 vs 9.7 mm (P = 0.0005), 13 vs 13 (P = NS), and 7.0% (43/611) vs 9.4% (18/191) (P = NS), respectively.

Conclusion: The high false-negative result for MRI-detected lesions might arise from the difficulties in MRI-US correlation, which indicates the need for MRI-guided biopsy.