Ultrasonographic findings 6 months after 11-gauge vacuum-assisted large-core breast biopsy.

OBJECTIVE: To assess the ultrasonographic features of post-biopsy change 6 months after 11-gauge vacuum-assisted large-core breast biopsy of pathologically proven benign lesions. Using the literature as a reference, we hypothesized that large-core breast biopsy would result in tissue changes that may mimic malignancy and may be more apparent on ultrasonography than on mammography. METHODS: Two radiologists whose subspecialty is breast imaging retrospectively reviewed the pre-biopsy and 6-month follow-up sonograms of 24 patients with pathologically proven benign lesions. The images were assessed for the number and type of ultrasonographic features. A Breast Imaging Reporting and Data System (BI-RADS) category was assigned to each lesion before biopsy and at 6-month follow-up. The composition of breast tissue surrounding the lesion was assessed as fatty, mixed fibroglandular or dense. RESULTS: The frequency of ultrasonographic changes at 6 months after 11-gauge vacuum-assisted large-core breast biopsy was more frequent than the rate of post-biopsy change previously reported to occur mammographically. The nature of these changes may mimic malignancy in some cases. CONCLUSION: The ultrasonographic appearance of the breast after large-core breast biopsy may mimic malignancy and is, therefore, a potential pitfall when interpreting a post-biopsy sonogram.