Our study evaluated the significance of accompanying NME in invasive breast cancer on preoperative MR imaging and assess the factors affecting the significance. We found that 24.5 % IDC with mass feature was accompanied by NME on preoperative MR imaging. Among them, 55 % accompanying NME had malignant pathologic results. Especially, HER2 positivity was significantly associated with malignant pathologic results of NME. Our results suggest that the accompanying NME should be carefully investigated on preoperative MR images and individually determined according to molecular subtypes.