Mixed and Purely Hyperechoic Breast Masses: A Radiologic-Pathologic Review

Breast US is a mainstay of modern-day breast imaging, especially in the diagnostic and interventional realm. The BI-RADS atlas described six echo patterns relative to the subcutaneous mammary fat: anechoic, hypoechoic, complex cystic and solid, isoechoic, heterogeneous, and hyperechoic. Hyperechoic breast masses demonstrate increased echogenicity relative to subcutaneous mammary fat or equal to fibroglandular tissue. Pathologically, the hyperechoic pattern at breast US results from the intermingling of different components: adipose tissue, fibrous tissue or stroma, secretions, blood or vascularity, and calcifications. Most hyperechoic masses are benign, especially homogeneously hyperechoic masses. However, hyperechogenicity does not exclude malignancy. Two echo patterns have been identified in hyperechoic malignant lesions, including those with a hypoechoic center and hyperechoic rim known as the rim pattern and a mass with hyperechoic areas distributed through the mass known as a dispersed pattern. This article aims to illustrate the echogenic patterns of breast lesions and various benign and malignant hyperechoic breast lesions with radiologic-pathologic correlation and to increase awareness of heterogeneously hyperechoic breast lesions as a manifestation of malignancy.