Symbolic illustration of breast health and growth with a blooming tree within a woman's silhouette.

Navigating Atypical Breast Lesions: When to Worry and What to Do

Q: What exactly is Flat Epithelial Atypia (FEA)?

Flat Epithelial Atypia (FEA) is a condition where the cells in the terminal duct lobular units (TDLU) of the breast show atypical changes. This means the cells don't look normal and can be a sign of increased breast cancer risk. These changes involve one or more epithelial layers replacing normal epithelium within the TDLU acini, which are typically dilated and contain luminal calcifications. It's often detected through mammograms because of calcifications.

Q: Why is Flat Epithelial Atypia (FEA) considered important in the context of breast health?

The significance of Flat Epithelial Atypia (FEA) lies in its association with an elevated risk of breast cancer. The initial concerns arose from studies showing that some cases of FEA found on core needle biopsies (CNB) were actually more serious conditions like invasive cancer or ductal carcinoma in situ (DCIS) when surgically examined. Although recent studies suggest lower upgrade rates, this is due to improved lesion sampling, it still presents a risk. Its identification, particularly when found alongside other high-risk lesions like atypical ductal hyperplasia (ADH), prompts careful consideration and possible surgical intervention.

Q: How is Flat Epithelial Atypia (FEA) managed when discovered through a biopsy?

Management decisions for Flat Epithelial Atypia (FEA) identified through percutaneous biopsy depend on several factors. If the lesion is well-sampled, the risk of cancer upgrade is low. The necessity for surgical excision has been a topic of debate, particularly with the advent of more advanced biopsy techniques. However, thorough percutaneous sampling is key. Personal history of breast cancer can also influence decisions; women with a history of breast cancer have higher upgrade rates. Another reason for possible excision is the potential for the lesion to be upgraded to a 'true' high-risk lesion, indicating a significantly higher long-term breast cancer risk.

Q: What are radial scars and papillary lesions, and how do they relate to the discussion of breast health?

Radial scars and papillary lesions are other high-risk breast lesions mentioned. Radial scars, like FEA, can be challenging to manage. These lesions, when found on percutaneous biopsy, have a 25-30% risk of being upgraded to cancer, which often warrants surgical excision. Papillary lesions, if they exhibit atypia, also carry a similar risk of upgrade to cancer. These lesions, along with FEA, are important to consider due to the potential for underestimation of cancer during biopsies and the subsequent implications for patient management.

Q: What are the key implications of these high-risk breast lesions?

The primary implication of high-risk breast lesions such as Flat Epithelial Atypia (FEA), radial scars, and papillary lesions is the potential for an increased risk of breast cancer. The article highlights the importance of accurate diagnosis and appropriate management strategies. It stresses the need for understanding the nuances of these lesions and making informed decisions based on individual patient factors, the presence or absence of atypia, and the thoroughness of the biopsy. The goal is to balance the risks of over-treatment with the need to identify and address potentially cancerous conditions early on.

Reese Marlowe in Health & Wellness August 2025 • 5 min read.

"Understanding Flat Epithelial Atypia, Radial Scars, and Intraductal Papillomas for Informed Decisions About Breast Health"

High-risk breast lesions, identified through histologic epithelial abnormalities, elevate the risk of breast cancer due to potential underestimation during core needle biopsies or increased long-term risk. The rising use of screening mammography has led to more frequent diagnoses of these lesions through percutaneous image-guided biopsies.

For surgeons, understanding which lesions necessitate surgical excision to rule out associated malignancies is crucial. In the absence of concurrent malignancy, a high-risk lesion represents a histologic finding linked to an elevated breast cancer risk. Atypical ductal hyperplasia (ADH), atypical lobular hyperplasia (ALH), and lobular carcinoma in situ (LCIS) are well-known examples, with extensive research dedicated to them.

Beyond these, other challenging high-risk lesions include flat epithelial atypia (FEA), radial scars, and papillary lesions. This article reviews these latter high-risk lesions, providing clinical management recommendations to empower informed decisions about breast health.

Flat Epithelial Atypia (FEA): What It Means and How to Manage It

Symbolic illustration of breast health and growth with a blooming tree within a woman's silhouette.

First defined in 2003, Flat Epithelial Atypia (FEA), previously termed columnar cell change/hyperplasia with atypia, involves epithelial changes in the terminal duct lobular units (TDLU). Histologically, FEA comprises one or more epithelial layers replacing normal epithelium within the TDLU acini, which are typically dilated and contain luminal calcifications. The lesional cells are monomorphic, featuring round, uniform nuclei lacking normal basal polarity. FEA cells resemble those in atypical ductal hyperplasia/low-grade ductal carcinoma in situ (DCIS), but without the epithelial architectural complexity; hence, the atypical epithelium is “flat.”

FEA is a rare finding, detected in 0.7-12.2% of percutaneous breast biopsies, often prompted by mammographic calcifications found during screening. It frequently co-occurs with other high-risk lesions, especially ADH, with 27-53% of core biopsies showing FEA. Due to its rarity and recent definition, the need for surgical excision of FEA diagnosed by CNB has been debated. Initially, excision was routine due to the presence of cytologic atypia.

Earlier Reports: Showed 10-30% of cases had invasive cancer or DCIS at surgical excision, supporting routine surgical excision.
Recent Studies: Indicate lower upgrade rates, likely from improved lesion sampling using larger needles, vacuum-assisted techniques, and radiologic-pathologic concordance.
Thorough Percutaneous Sampling: When all microcalcifications are removed, upgrade rates drop to 0-7%.
Personal History Matters: Berry et al. found higher upgrade rates in women with a personal history of breast cancer (50%) versus those without (11%).

Emerging literature suggests isolated FEA (focal FEA) has lower malignancy rates (<3%), making subsequent surgical excision potentially unnecessary. Besides cancer findings, atypical hyperplasia (AH) or LCIS are often found at surgical excision of FEA core biopsy sites. Thus, another reason to excise FEA diagnosed by core biopsy is the potential upgrade to a “true” high-risk lesion, indicating a substantially increased long-term breast cancer risk. While ALH and LCIS are occasionally reported, ADH is the most common high-risk lesion found at surgical excision (25–30% of cases).

Making Informed Decisions

FEA, radial scars, and papillary lesions identified via percutaneous biopsy can be challenging to manage because of potential cancer underestimation. Radial scars and papillary lesions with atypia have a 25-30% risk of upgrade to cancer, warranting surgical excision. For FEA, radial scars, and papillary lesions without atypia, cancer upgrade risks are low if the lesion is well-sampled.

Information should be considered when discussing with patients their preferences for surgical excision and longer-term surveillance. Long-term breast cancer risk for women with these lesions is modest (relative risk of 2) in the absence of atypical hyperplasia.

By understanding the nuances of these lesions, individuals can work closely with their healthcare providers to develop personalized management plans that balance the need for accurate diagnosis and risk reduction with the desire to minimize unnecessary interventions. This collaborative approach ensures the best possible outcomes for long-term breast health.

About this Article -

This article was crafted using a human-AI hybrid and collaborative approach. AI assisted our team with initial drafting, research insights, identifying key questions, and image generation. Our human editors guided topic selection, defined the angle, structured the content, ensured factual accuracy and relevance, refined the tone, and conducted thorough editing to deliver helpful, high-quality information.See our About page for more information.

This article is based on research published under:

DOI-LINK: 10.1245/s10434-017-5980-6, Alternate LINK

Title: Challenging Atypical Breast Lesions Including Flat Epithelial Atypia, Radial Scar, And Intraductal Papilloma

Subject: Oncology

Journal: Annals of Surgical Oncology

Publisher: Springer Science and Business Media LLC

Authors: Jennifer M. Racz, Jodi M. Carter, Amy C. Degnim

Published: 2017-08-01

Everything You Need To Know

What exactly is Flat Epithelial Atypia (FEA)?

Flat Epithelial Atypia (FEA) is a condition where the cells in the terminal duct lobular units (TDLU) of the breast show atypical changes. This means the cells don't look normal and can be a sign of increased breast cancer risk. These changes involve one or more epithelial layers replacing normal epithelium within the TDLU acini, which are typically dilated and contain luminal calcifications. It's often detected through mammograms because of calcifications.

Why is Flat Epithelial Atypia (FEA) considered important in the context of breast health?

The significance of Flat Epithelial Atypia (FEA) lies in its association with an elevated risk of breast cancer. The initial concerns arose from studies showing that some cases of FEA found on core needle biopsies (CNB) were actually more serious conditions like invasive cancer or ductal carcinoma in situ (DCIS) when surgically examined. Although recent studies suggest lower upgrade rates, this is due to improved lesion sampling, it still presents a risk. Its identification, particularly when found alongside other high-risk lesions like atypical ductal hyperplasia (ADH), prompts careful consideration and possible surgical intervention.

How is Flat Epithelial Atypia (FEA) managed when discovered through a biopsy?

Management decisions for Flat Epithelial Atypia (FEA) identified through percutaneous biopsy depend on several factors. If the lesion is well-sampled, the risk of cancer upgrade is low. The necessity for surgical excision has been a topic of debate, particularly with the advent of more advanced biopsy techniques. However, thorough percutaneous sampling is key. Personal history of breast cancer can also influence decisions; women with a history of breast cancer have higher upgrade rates. Another reason for possible excision is the potential for the lesion to be upgraded to a 'true' high-risk lesion, indicating a significantly higher long-term breast cancer risk.

What are radial scars and papillary lesions, and how do they relate to the discussion of breast health?

Radial scars and papillary lesions are other high-risk breast lesions mentioned. Radial scars, like FEA, can be challenging to manage. These lesions, when found on percutaneous biopsy, have a 25-30% risk of being upgraded to cancer, which often warrants surgical excision. Papillary lesions, if they exhibit atypia, also carry a similar risk of upgrade to cancer. These lesions, along with FEA, are important to consider due to the potential for underestimation of cancer during biopsies and the subsequent implications for patient management.

What are the key implications of these high-risk breast lesions?

The primary implication of high-risk breast lesions such as Flat Epithelial Atypia (FEA), radial scars, and papillary lesions is the potential for an increased risk of breast cancer. The article highlights the importance of accurate diagnosis and appropriate management strategies. It stresses the need for understanding the nuances of these lesions and making informed decisions based on individual patient factors, the presence or absence of atypia, and the thoroughness of the biopsy. The goal is to balance the risks of over-treatment with the need to identify and address potentially cancerous conditions early on.