Lesions with Obscured Margins

Due to the limitaions of film mammography, a well-circumscribed mass obscured by normal surrounding tissue may appear similar to an infiltrating malignant mass with ill-defined margins. Due to the superimposition of three-dimensional tissue structures, the margins of a mass may be obscured and look ill defined. In cases where the breast may be dense, the margins may appear obscured because both benign and malignant lesions develop in lobules which are heavily surrounded by normal extralobular connective tissue. Perhaps a different mammographic view will reveal something more about a lesion with obscured margins. Otherwise, the lesion is identified as equivocal and additional evaluation is necessary.