Characteristic features and usefulness of MRI in breast cancer in patients under 40 years old: correlations with conventional imaging and prognostic factors

The purpose of this study was to evaluate the characteristic features and usefulness of magnetic resonance imaging (MRI) of breast cancer in women under 40 years old that are correlated with conventional imaging and prognostic factors. We performed a retrospective review of the clinical, radiological and pathological features of patients under 40 years old with breast cancer at our institution between October 2007 and December 2010. A total of 99 women were included. The most common MRI findings were a mass or multiple masses (82.8 %) similar to those observed with mammography (50.5 %) and ultrasonography (90.9 %). The sensitivity of both MRI and ultrasonography for detecting a primary breast lesion was 100 % compared to 87.4 % with mammography. After preoperative MRI, the surgical plan changed in 35.7 %. The rim enhancement of the mass was a significant and independent predictor of a higher histological grade (p = 0.005), negative expression of ER (p = 0.01) and PR (p = 0.02). The clumped enhancement of the non-mass lesion was also associated with positive LN metastasis (p = 0.04). Breast cancer in women under 40 years old frequently presents as suspicious masses on both conventional imaging and MRI. Ultrasonography and MRI both showed excellent sensitivities that were better than those of mammography in young women with dense breasts. Additionally, MRI can play an important role in preoperative planning, and some BI-RADS MRI features can be used to predict breast cancer prognosis in this age group.