Imaging features of invasive lobular carcinoma: comparison with invasive ductal carcinoma

Purpose. The aim of this study was to evaluate the imaging findings of invasive lobular carcinoma (ILC) compared to those of invasive ductal carcinoma (IDC). Materials and methods. The study included ILCs (n = 27) and IDCs (n = 85). Imaging findings were retrospectively evaluated, according to the BI-RADS lexicon. We compared the imaging findings, multiplicity, and magnetic resonance imaging (MRI) detection accuracy of ILC with those of IDC. Results. At mammography, normal findings and mass lesions were more frequent with ILCs (14.8% and 59.2%, respectively) than with IDCs (1.2% and 44.7%, respectively) (P = 0.009). With ultrasonography (US), posterior acoustic shadowing was more frequently seen in ILCs (59.2%) than in IDCs (15.8%) (P < 0.001). With MRI, both ILCs and IDCs most commonly appeared as a heterogeneously enhancing, irregular mass with a spiculated border. Multifocality was more frequently associated with ILCs (40.7%) than with IDCs (14.1%) (P = 0.002). However, multicentricity and bilaterality were not different between the two groups. The sensitivity and specificity of MRI for the detection of multiplicity were 91.6% and 73.3%, respectively, for ILCs and 83.3% and 80.3%, respectively, for IDCs. Conclusion. Normal findings, mass lesions on mammography, and posterior acoustic shadowing on US were more frequently associated with ILCs than with IDCs. Multifocality was more prevalent with ILCs than with IDCs.