Role of Magnetic Resonance Imaging in the Preoperative Staging and Work-Up of Patients Affected by Invasive Lobular Carcinoma or Invasive Ductolobular Carcinoma.

Purpose: The prevalence of invasive lobular carcinoma (ILC), the second most common type of breast cancer, accounts for 5%-15% of all invasive breast cancer cases. Its histological feature to spread in rows of single cell layers explains why it often fails to form a palpable lesion and the lack of sensitivity of mammography and ultrasound (US) to detect it. It also has a higher incidence of multifocal, multicentric, and contralateral disease when compared to the other histological subtypes. The clinicopathologic features and outcomes of Invasive Ductolobular Carcinoma (IDLC) are very similar to the ILC. The purpose of our study is to assess the importance of MRI in the preoperative management and staging of patients affected by ILC or IDLC. Materials and Methods: We identified women diagnosed with ILC or IDLC. We selected the patients who had preoperative breast MRI. For each patient we identified the areas of multifocal, multicentric, or contralateral disease not visible to standard exams and detected by preoperative MRI. We analyzed the potential correlation between additional cancer areas and histological cancer markers. Results: Of the 155 women who met our inclusion criteria, 93 (60%) had additional cancer areas detected by MRI. In 61 women, 39,4% of the overall population, the additional cancer areas were confirmed by US/tomosynthesis second look and biopsy. Presurgical MRI staging changed surgical management in the 37,4% of the patients. Only six patients of the overall population needed a reoperation after the initial surgery. No statistically significant correlation was found between MRI overestimation and the presence of histological peritumoral vascular/linfatic invasion. No statistically significant correlation was found between additional cancer areas and histological cancer markers. Conclusions: Our study suggests that MRI is an important tool in the preoperative management and staging of patients affected by lobular or ductolobular invasive carcinoma.