The spectrum of breast asymmetries: imaging features, work-up, management.

Asymmetry may be the only manifestation of breast cancer on standard mammographic views. The terminology used to describe breast asymmetries changed in 2003 with the publication by the American College of Radiology of the fourth edition of its Breast Imaging Reporting and Data System (BI-RADS). This article describes and illustrates the four types of asymmetry found at mammography (asymmetry, global asymmetry, focal asymmetry, and developing asymmetry). For each type of asymmetry, the article also indicates the frequency of occurrence, likelihood of malignancy, standard imaging work-up, assessment, and management.