by Kimberly Wood, MD MSc FRCPC
March 7, 2023
Radial scar, also known as a complex sclerosing lesion, is a non-cancerous growth characterized by an increased number of glands and ducts around a central scar. Although non-cancerous, radial scars are associated with a small increased risk of developing breast cancer when compared to women without radial scars.
Most radial scars in the breast do not cause any symptoms and the growth is found incidentally when imaging of the breast is performed for other reasons. Rarely, the growth becomes large enough to be felt as a lump in the breast.
At present doctors do not know what causes this condition to develop.
Radial scars can be diagnosed after a small sample of tissue is removed in a procedure called a biopsy. The diagnosis can also be made after a larger area of tissue is removed in a procedure called a resection.
For many patients, a radial scar is discovered incidentally after a biopsy or resection is performed for another reason. However, some radial scars can be seen on screening mammography/ultrasound, especially when they are greater than 1 cm in size. Because a radial scar can look very similar to breast cancer on mammography or ultrasound, a biopsy is performed to confirm the diagnosis.
When examined under the microscope, a radial scar is made up of abnormal connective tissue that pathologists describe as fibrosis. The abnormal connective tissue is sometimes described as showing elastosis or elastotic because it contains numerous elastic fibers. Small irregularly shaped ducts and glands are often seen trapped within the area of fibrosis. Other non-cancerous changes that are often seen in the tissue surrounding a radial scar include usual ductal hyperplasia (UDH), cysts, and apocrine metaplasia.