Flat epithelial atypia (FEA)

by Jason Wasserman MD PhD FRCPC
July 16, 2024

Background:

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

What are the symptoms of flat epithelial atypia?

FEA does not cause any symptoms on its own, and it is typically discovered incidentally during mammographic screening or as part of a biopsy performed for other reasons.

What causes flat epithelial atypia?

The exact cause of flat epithelial atypia is not well understood, but several factors may contribute to its development:

  • Reproductive hormones: Hormonal factors, particularly those related to estrogen and progesterone, are believed to play a role in the development of FEA. Hormonal fluctuations during the menstrual cycle, pregnancy, and menopause may influence the growth of atypical epithelial cells.
  • Genetic factors: Genetic predisposition may also be a contributing factor. Women with a family history of breast cancer or other benign breast conditions may have a higher likelihood of developing FEA.
  • Cellular and molecular changes: FEA is thought to arise from genetic and epigenetic changes at the cellular level that lead to the atypical proliferation of epithelial cells. These changes can include mutations in genes that regulate cell growth and differentiation.

How is this diagnosis made?

The diagnosis of FEA can be made after a small tissue sample 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 conditions in the same breast.

Microscopic features of flat epithelial atypia

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 color when compared to normal epithelial cells. Pathologists use the word atypical to describe these abnormal cells.

The columnar-shaped epithelial cells produce a fluid 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. 

Other conditions 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.

About this article

Doctors wrote this article to help you read and understand your pathology report for FEA of the breast. Contact us with any questions about this article or your pathology report. Read this article for a more general introduction to the parts of a typical pathology report.

Other helpful resources

Atlas of Pathology
A+ A A-

Did you find this article helpful?