Definition

A benign (not cancer) area of hardened tissue in the breast that looks like a scar when viewed under a microscope. Complex sclerosing lesions often occur in both breasts, and more than one lesion is usually present in each breast. They usually cannot be felt and do not cause symptoms but may look like breast cancer on a mammogram, especially if the lesions are large. A biopsy is usually needed to tell the difference between these lesions and breast cancer. Complex sclerosing lesions may slightly increase the risk of breast cancer. Also called radial scar.