RESUMO
Invasive lobular carcinoma (ILC) accounts for 5-15% of breast cancers. In comparison to other types of breast cancer, ILC is more likely to be associated with multifocal and contralateral breast involvement as well as a tendency to a diffuse infiltrative growth pattern which can represent a diagnostic challenge. The National Institute of Clinical Excellence guidelines in 2009 recommended the use of magnetic resonance imaging (MRI) in the preoperative assessment of ILC. This study aims to assess compliance with the guidelines in two District General Hospitals and the utility of MRI in the investigation of ILC. All cases of ILC between 2011 and 2013 were retrospectively identified from the pathology database and their breast imaging findings, pathology report, and operative intervention were reviewed. A total of 126 patients were identified with ILC, of these 46 had MRI preoperatively (36.5%). MRI upgraded mammography/ultrasound diagnoses in 10 patients (21.7%). MRI showed multicentric unilateral disease in 17 patients (37.0%) occult on ultrasound/mammogram, with these patients undergoing mastectomy and 16/17 (94.1%) confirmed multifocality on pathology. MRI showed a contralateral lesion in 9 patients (19.6%), four (8.7%) of which were malignant and had bilateral surgery, and five (10.9%) were benign on further imaging/biopsy. MRI also downgraded three patients (6.5%) to unifocal disease with reported multifocal appearances on mammography/ultrasound, and these patients underwent breast-conserving surgery. MRI adds significant additional information to mammograms/ultrasound in ILC and should be undertaken in all such cases preoperatively assuming no contraindication.