Is breast MRI a helpful additional diagnostic test in suspicious mammographic microcalcifications?

Microcalcifications are a common finding in mammography and usually require invasive procedures to diagnose or exclude malignancy. As many microcalcifications are due to benign lesions, we wanted to assess whether breast MRI as an additional diagnostic tool may be used to distinguish benign from malignant in this setting.

Eligible for this retrospective, IRB-approved observational study were 858 consecutive patients (mean age 54±11years) undergoing stereotactically-guided biopsies of suspicious mammographic microcalcifications during three year at our institution. Finally included were 152 patients who also underwent breast MRI <8weeks prior to biopsy. In case of malignant or lesions of uncertain malignant potential, subsequent surgery was performed. Benign findings were confirmed by imaging follow-up. BI-RADS category assignments from the original mammography and breast MRI reports were compared to the final diagnosis (benign vs. malignant) to determine diagnostic benchmarks.

Histopathology revealed 81 benign (53.3%), 41 DCIS (27%) and 30 (19.7%) invasive cancers. Sensitivity, specificity, positive and negative predictive values for breast MRI were 97.2% (69/71), 39.5% (32/81), 58.5% (69/118) and 94.1% (32/34), respectively. Thus, 32/81 unnecessary biopsies in benign lesions (39.5%) may have been avoided, missing 2/71 malignant lesions (2.8%), both DCIS G2.

Breast MRI as an additional diagnostic tool can be used to accurately distinguish benign from malignant mammographic microcalcifications and may thus be helpful to reduce unnecessary breast biopsies.