Magnetic resonance imaging-guided breast biopsy in lesions not visualized by mammogram or ultrasound.

The use of magnetic resonance imaging (MRI) for the diagnosis and evaluation of breast lesions is still in evolution. The aim of this study was to evaluate the outcome of MR-guided biopsy for suspicious lesions seen on MRI but not visualized by mammography or ultrasound. A retrospective review was conducted on all patients undergoing MRI-guided core needle biopsy at a National Cancer Institute-designated comprehensive cancer center. Biopsies were performed using a 1.5-Tesla MR with a seven-channel breast coil taking six cores in a clock face configuration with a 10-gauge vacuum-assisted VACORA biopsy device. One hundred twenty-seven patients underwent 187 biopsies without major complication. The lesion size ranged from 4 to 12 mm. Pathology on MRI-guided core biopsy material revealed 126 (68%) benign lesions. Of these, 12 were intraductal papillomas and two were fibroadenomas. Sixty-one (32%) were deemed clinically significant and included the following pathology: invasive cancer 19 patients (10%), ductal carcinoma in situ (DCIS) in 25 patients (13%), atypical ductal hyperplasia (ADH) 15 patients (8%), and lobular carcinoma in situ in one patient (1%). There were two specimens upgraded from ADH to DCIS and one specimen that was biopsied was called ADH but there was no residual atypia on final pathology. With a median follow-up of 24 months, there were no patients with benign pathology returning with a clinically significant lesion later. MRI-guided biopsy provides an accurate and safe method for sampling suspicious lesions when no other reasonable means of biopsy is available. MRI-guided biopsy yielded clinically significant findings in approximately one-third of the sampled specimens. This technique can provide a good representative sample of clinically significant pathology. MRI-guided biopsy is a relatively new modality, which can provide a nonsurgical diagnostic specimen in the absence of mammographic or ultrasound findings.