Breast, complex sclerosing lesion

Complex sclerosing lesions are benign breast masses characterized by a central dense collagenous stroma with a radiating proliferation of benign breast elements, including cysts, usual ductal hyperplasia, and adenosis. Sclerosing lesions can have irregular outlines and entrapment of small irregular tubules. They can therefore mimic malignancy both radiologically and in histologic sections. Although benign, sclerosing lesions are often excised particularly when they form larger masses or based on the level of radiologic concern.

This slide is from the excision specimen. See Related Content for the biopsy specimen.