39. Complex sclerosing lesion

Overview

Staining: HE

Organ: Breast

Description:

There is a central lesion of fibrosis/fibroelastosis, with nodules of epithelial hyperplasia around. The fibrosis has a star-like shape, which is why it’s often described as a stellate lesion.

Among the epithelial cells in the nodules, spindle-shaped cells can be seen. These cells are myoepithelial cells. The epithelial cells show no or only mild atypia.

Diagnosis: Complex sclerosing lesion

Causes:

• Nothing in particular.

Theory:

Close-up

This is a type of fibrocystic lesions. Complex sclerosing lesion is not a harmful condition, however it can cause similar clinical features as invasive breast cancer and must therefore be distinguished from it. Both can cause a palpable nodule and skin retraction.

The importance of this tumor-like lesion is therefore to distinguish it from cancer. As myoepithelial cells are not present in cancer, we can be certain that this slide is a complex sclerosing lesion and not a tumor. Also, the very mild degree of atypia here is not suggestive of cancer.

Ducts are not visible as the hyperplastic lesion compresses the ducts to the point where they’re no longer visible.

The topic list used to call this “intraductal papilloma”, but that’s wrong. The topic list is corrected as of the spring semester of 2020.