MRI patterns of invasive lobular cancer: T1 and T2 features

The aim of this study was to describe magnetic resonance imaging (MRI) patterns in 21 patients with histologically proven invasive lobular cancer (ILC) of the breast. We retrospectively reviewed MR images of 21 out of 24 women with ILC of the breast. Three women were excluded from the study because they underwent neoadjuvant chemotherapy after MRI. Thirteen of the 24 women had positive clinical findings. All 24 patients underwent mammography, sonography and MRI. MRI was performed to evaluate disease extent and multifocality/multicentricity before modified radical mastectomy (n=5) or quadrantectomy (n=16). Two experienced radiologists reviewed the MRI scans and described the tumour patterns. We identified five morphological patterns of ILC: a solitary mass with irregular margins (n=8); a mass with smooth margins (n=5); multiple small enhancing foci with interconnecting enhancing strands (n=4); dominant lesion surrounded by small foci (n=3); one MR examination was negative. Architectural and dynamic features are important in the interpretation of breast MRI findings. ILC may be detected on MRI as solitary or multiple lesions that correspond to tumour morphology on pathologic examination. False-negative MRI findings do occur in a small percentage of ILC