Breast background echoes of uniform fibroglandular type refers to the tissue composition of the breast under ultrasound. Uniform echoes refer to the uniform density of the breast, and fibroglandular type refers to the more glandular component of the breast. Breast background echoes are divided into 3 categories according to the density and distribution of glands within the breast tissue: 1. Homogeneous background echo-fat type: indicates that the breast tissue is mainly composed of fat and uniformly echogenic strips of supporting structures. 2. Homogeneous background echo-fibroglandular type: manifests itself as a thick layer of homogeneous fibroglandular echoes located below a thin layer of hypoechoic fat lobules, and the lesion may be located in the fibroglandular layer or in the combination of the fibrotic layer or its fat. 3. Inhomogeneous background echogenicity: This is characterized by multiple small patches of echogenic enhancement mixed with areas of hyperechoicity. Because different breast densities affect the sensitivity of lesion detection, characterization of the background echoes of the breast can indicate the accuracy of the clinician’s findings.