Preoperative Staging of Invasive Lobular Carcinoma: CEM or CE-MRI?

Purpose: Invasive lobular carcinoma (ILC) exhibits an infiltrative growth pattern with frequent multifocal, multicentric, and bilateral involvement, often leading to underestimation on conventional imaging. This study aimed to compare the diagnostic performance of contrast-enhanced mammography (CEM) and contrast-enhanced magnetic resonance imaging (CE-MRI) for preoperative locoregional staging of ILC. Materials and methods: Women with histologically confirmed ILC who underwent both CEM and CE-MRI for preoperative staging were included in this retrospective single-center study. 46 of 70 consecutive patients met the inclusion criteria. Two dedicated breast radiologists independently and blindly reviewed all examinations. The number of enhancing lesions, maximum lesion diameter, multicentricity, and bilaterality were recorded. Quantitative variables were analyzed using the Wilcoxon signed-rank test, while paired categorical variables were compared using McNemar's test. Inter-reader agreement was assessed using Cohen's kappa and intraclass correlation coefficients. Results: CEM and CE-MRI showed strong concordance in lesion size assessment, with no significant differences between modalities (p > 0.05). Agreement for bilaterality detection was high for both techniques, with no statistically significant differences. CE-MRI detected a significantly higher number of multicentric cases compared with CEM (p < 0.05). Inter-reader agreement was good to excellent across all parameters. Conclusion: CEM demonstrates comparable performance to CE-MRI for assessing lesion size and bilaterality in ILC. However, CE-MRI remains superior for detecting multicentric disease, a key factor in surgical planning. CEM may represent a complementary imaging tool in selected cases. Key points: · CEM and MRI show comparable accuracy for lesion size assessment.. · MRI demonstrates superior sensitivity for detecting multicentric disease.. · Multicentricity detection may impact surgical planning in selected patients.. Citation format: · Colarieti A, Minelli P, Bonetti A et al. Preoperative Staging of Invasive Lobular Carcinoma: CEM or CE-MRI?. Rofo 2026 DOI 10.1055/a-2906-1608.