MR Imaging Findings in Molecular Subtypes of Breast Cancer According to BIRADS System

To evaluate magnetic resonance imaging (MRI) findings, according to Breast Imaging‐Reporting and Data System (BI‐RADS), and to relate them with molecular subtypes of breast cancer. The MRI findings were reviewed retrospectively in 201 women diagnosed of invasive breast cancer confirmed by surgery and were compared with the molecular subtypes. Following the BI‐RADS, MRI findings included disease type, size, enhancement, morphology and contrast kinetics. In mass‐like lesion types were studied shape, margin and enhancement, and in nonmass‐like lesion types, distribution modifiers and internal enhancement. Chi‐squared analysis showed significant association (p < 0.01) between molecular subtypes and lesion type on MRI and histologic grade. Shape, margin and mass enhancement (p < 0.05) also showed significant association among molecular subtypes. Triple negative were more frequently unifocal and mass‐like lesion, high histologic grade, round shape, smooth margin, and rim enhancement. Luminal‐A were more frequently low grade, mass‐like lesion, irregular shape and spiculated or irregular margin. Luminal‐B were more frequently moderate‐low grade, mass‐like lesion, nonirregular shape and spiculated margin. HER‐2‐enriched were more frequently moderate grade, nonmass‐like lesion and multicentric lesions were more present than in other subtypes. There are significantly different MRI features, according to BI‐RADS, between the molecular subtypes breast cancer.