Breast Magnetic Resonance Imaging of Multicentric, Multifocal and Bilateral Cancer — A Case-based Review

Abstract

Multifocal or multicentric breast cancer can be difficult to detect on mammography or ultrasound, particularly in patients with dense breast tissue. A multimodality approach that includes breast magnetic resonance imaging (MRI) is indicated, particularly when conservative surgery is being considered as it is the most sensitive technique for identifying additional sites of disease. However, its influence on recurrence and survival rates has yet not been clearly established, and false-positive cases may lead to more aggressive management and treatment. Radiologists should therefore be aware of relevant breast MRI findings. Infiltrating carcinomas, contralateral unsuspected carcinomas, occult carcinomas, false-positive cases and post-chemotherapy changes. Several cases of multiple-site breast carcinomas and their corresponding mammographic, ultrasound and MRI features have been reviewed for this article, in which the definition and differences between multifocal, multicentric and contralateral breast carcinoma are explained and the most relevant imaging findings on MRI are illustrated and correlated with mammogram and ultrasound findings. Finally, the role of breast MRI in the pre-operative assessment of breast cancer is discussed.