Flat epithelial atypia (FEA)

by Vanessa Grace M. De Villa-Atienza, MD, DPSP
March 9, 2022

What is flat epithelial atypia (FEA)?

Flat epithelial atypia (FEA) is a non-cancerous condition that develops in the breast. This change can only be seen after tissue from the breast is examined under the microscope by a pathologist. FEA is a common condition and it is often seen in breast tissue removed for another reason.

breast normal anatomy

How do pathologists make the diagnosis of flat epithelial atypia?

The diagnosis of FEA can be made after a small sample of tissue is removed from the breast in a procedure called a core needle biopsy. The biopsy may be performed after calcifications were seen on mammography. FEA can also be discovered incidentally in tissue removed to diagnose or treat cancer or other non-cancerous condition in the same breast.

What does flat epithelial atypia look like under the microscope?

In normal, healthy breast tissue, the ducts and glands are lined by a single layer of epithelial cells. Pathologists describe these cells as cuboidal because each cell is as tall as it is wide (like a square). In FEA the glands are lined by one or more layers of cuboidal or columnar-shaped epithelial cells that are abnormal in shape, size, or colour when compared to normal epithelial cells. Pathologists use the word atypia to describe these abnormal cells.

The columnar-shaped epithelial cells produce a fluid that is rich in calcium. Over time, some of the calcium in the fluid is left in the tissue where it creates calcifications. These calcifications are denser than normal breast tissue which allows them to be seen on mammography. 

What other breast conditions are associated with flat epithelial atypia?

FEA is often seen together with other non-cancerous changes including:

FEA may also be seen in the breast tissue surrounding a pre-cancerous condition or cancer. Some of the more commonly associated conditions include:

Is flat epithelial atypia associated with an increased risk of developing breast cancer?

Some cases of FEA may progress to cancer, but the risk of progression is very low. Studies have shown that women with flat epithelial atypia have a 1.5 times greater risk of developing breast cancer when compared to women without FEA.

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