Khalayleh H, et al. - In this retrospective analysis, researchers contrasted tumor size assessed by the different imaging modalities to pathologic size across breast densities. The sample consisted of 183 female patients (197 breast cancers) diagnosed and operated for primary breast cancer at a single center. Data reported that the mean pathologic tumor size was 23.0 ± 19.3 mm. Mean tumor size did not vary significantly with mammography or MRI, however, the ultrasound significantly underestimated the mean tumor size. Breast density was not affected by any imaging modality to the accuracy of the tumor size assessment. Ultrasound may underestimate the size of a tumor in the breast. Treatment decisions which take tumor size into account can be made equally reliably in patients with high or low breast density.