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

ABSTRACT

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% 1% 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.