Magnetic resonance-guided vacuum-assisted breast biopsy: results in 100 Japanese women.

Purpose: The aim of this study was to clarify the frequency of malignancy and the histopathological characteristics of the lesions in patients undergoing magnetic resonance imaging (MRI)-guided vacuum-assisted biopsy (VAB).

Materials And Methods: A retrospective review of 100 consecutive patients with 102 lesions who had undergone MRI-guided VAB was performed. The biopsies were performed on a 1.5-T MR scanner using a commercially available biopsy system. None of the lesions seen with MRI could be detected by mammography or second-look ultrasonography.

Results: The average lesion sizes of the focus, mass, and nonmass lesions before the biopsy were 4.5, 8.2, and 21 mm, respectively. Twelve patients (12%) had lesions located in the deep portion of the breast, close to the pectoral muscle. The biopsy was successfully performed without important side effects in all patients. Histopathological findings were invasive ductal carcinoma in 6 (6%), in situ carcinoma in 28 (27%), and high-risk and benign in 68 (67%). Two high-risk lesions were upgraded to ductal carcinoma in situ (DCIS), and three DCIS lesions were upgraded to invasive ductal carcinoma at surgical excision.

Conclusion: The high rate of DCIS might be a unique feature among Japanese women. However, MRI-guided VAB is necessary for MRI-only visible suspicious lesions in Japan.