T2 Hyperintense Lesions on Breast MRI - Is the Assumption of Benignity Justified?

Introduction: This study aims to evaluate the outcomes of breast MRI-guided vacuum assisted biopsies (MVAB) performed on lesions with high T2 signal. Materials and Methods: We retrospectively collected of all MVAB performed at our institution between January 2016 and December 2021 for high T2 lesions. T2 hyperintensity was defined as equal or higher signal than normal lymph node. The correlation between various demographic and imaging characteristics and the binary pathological outcome (benign vs malignant) was evaluated. Results: In total, 174 biopsies from 165 women met the inclusion criteria and were included in the cohort. Malignancy was detected in 35 lesions (20%), most commonly ductal carcinoma in situ (DCIS, 57%), followed by infiltrating ductal carcinoma (IDC, 40%). The most common benign diagnosis was fibrocystic changes (FCC, 38%). In 19 lesions MVAB detected high-risk pathology, 3 of which were upgraded to malignancy. Older age (Mean 61 vs 54 years, P = .04), washout kinetics (29% vs 13%, P = .01), and indication for extent of disease evaluation (53% vs 32%, P = .06) were the strongest predictors of malignancy. Lesion size and morphology were not significantly associated with outcome. Conclusions: Given the considerable cancer rate, T2 hyperintensity should be used with caution as a benign indicator and not as a sole criterion for ruling out malignancy. Additional factors such as patient age, kinetic features, and MRI indication should be considered to improve diagnostic accuracy.