Breast ultrasound is a highly sensitive imaging method, but lacks specificity when it comes to characterizing breast lesions. In this context, elastography has been developed. This non-invasive technique, coupled with ultrasound, can be used to assess tissue hardness (or elasticity) or relative displacements, providing an image of elasticity or deformation.In order to situate the role of ultrasound elastography, among other imaging explorations, in the management of breast lesions, the work we carried out, focused on 375 breast masses, set out to meet the following objectives: - Determine the diagnostic performance of ultrasound elastography in the characterization of benign and malignant breast lesions. - To analyze the elastographic characteristics of breast lesions as a function of palpability, mammographic visibility, size, histological type, infiltrative nature, histopronostic grade and tumor progression potential, and to assess the influence of lesion size and depth on the diagnostic performance of elastography.