If breast asymmetry has shown up in your mammogram results, you might be imagining the scariest possibilities. We understand. Although asymmetry is actually quite common, hearing your doctor throw around technical terms to explain it can be unnerving.
Don’t worry; we’re here to address your concerns in the simplest way possible. We’ll walk you through what asymmetry in mammograms means and the next steps, among other important insights. Let’s start with the biggest concern.
What does asymmetry mean in a mammogram report?
Breast asymmetry refers to the difference in density of breast tissue between two breasts in a mammogram report. While breasts typically have symmetric density, it is still common to find asymmetric density. While this is not reason for concern, further tests may be required to rule out any other suspicious findings.
Types of Breast Asymmetry and What They Mean in a Mammogram
To determine asymmetry, radiologists look at breast density but also consider breast size, volume and form. They then use the Breast Imaging Reporting and Data System (BI-RAD) to categorize the asymmetry.
According to the BI-RAD, the following are four types of asymmetry likely to appear in your mammogram report:
1. One-view Asymmetry
This type of asymmetry refers to a difference in breast tissue density as seen in only one view or projection on a mammogram. One-view asymmetry occurs in 20.5% of all mammograms and is often due to non-cancerous density changes. It’s usually classified as BI-RADS 2, meaning benign, and a 6-month imaging follow-up is recommended to manage it. That’s unless further testing reveals any other suspicious features about the breast tissues.
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2. Focal Asymmetry
This refers to asymmetric breast tissue seen on two projections on the mammogram. It involves looking at small localized sites in one breast and comparing them to the same sites in the other breast. A solitary focal asymmetry without any architectural distortion, underlying mass or suspicious features is classified as BI-RADS 3, meaning likely benign. There is a 21% chance of getting this type of breast asymmetry in a mammogram report, and it’s usually not breast cancer.
3. Developing Asymmetry
A type of focal asymmetry is when new asymmetric breast tissue appears or seems to have grown or changed compared to prior imaging or exams. Ideally, breast tissue is supposed to be less dense as you age, so this type of asymmetry triggers more concern.
Such breast asymmetry may be benign if due to a cyst or scarring from an injury or surgery. Otherwise, developing asymmetric breast tissue is classified as BI-RADS 4 (i.e., suspicious). Luckily, it occurs in only 4.4% of cases, but regular mammograms and further testing are recommended.
4. Global Asymmetry
This type of breast asymmetry occurs when more than a quadrant of one breast has more dense tissue than the other in the same area. It occurs in around 3% of mammograms and is usually a benign normal variant. That’s why it is classified as BI-RADS2.
Is your breast asymmetry a sign of cancer?
Breast asymmetry doesn’t usually indicate cancer. In fact, one study looked at 201 patients with four types of breast asymmetry and only found six cases of invasive cancer.
Still, medical professionals advise doing additional testing and regular breast cancer screening since it’s unclear how breast asymmetry impacts the risk of developing breast cancer.
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It may depend on what caused the breast asymmetry. Most causes of asymmetry are benign (non-cancerous), but let’s break down a few of the causes that could be mistaken for breast cancer symptoms on a mammogram:
Fibrocystic changes
Feeling a lump in one or both breasts is enough to send you down a spiral of worry. However, according to the American Cancer Society, many breast lumps are usually due to fibrocystic changes - non-cancerous changes to the fibrous breast tissues. In some cases, you may require a biopsy and additional imaging tests to be sure it’s not breast cancer.
Pseudoangiomatous Stromal Hyperplasia (PASH)
PASH are harmless breast lesions (scarring on the breast tissue). It doesn’t cause cancer or impact the risk of getting it. There are actually less than 200 cases reported since it was first described in a research in 1986.
Stromal Fibrosis
This refers to the thickening and scarring of the connective tissue (stroma) that helps keep the mammary ducts and lobes in your breasts in place. According to research, it is usually a non-cancerous (i.e., benign) condition found on screening mammograms.
However, dense stromal fibrosis can increase the risk of breast cancer by causing inaccurate breast biopsy. If located next to cancerous cells, it would be difficult to catch any cancerous cells in the biopsy sample.
Dense breast
Breast density refers to how much glandular and fibrous tissue you have in your breast compared to fatty tissue. According to the American Cancer Society, roughly half of all women have dense breasts, so it’s not an abnormal trait. However, the dense breast tissue also makes it harder to detect cancer during a mammogram screening.
So, having dense breasts means you may have a slightly higher risk of breast cancer, especially if you have a medical or family history. More imaging tests and routine screening are great ways to get an accurate breast cancer diagnosis.
When should you worry about breast asymmetry?
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Breast asymmetry is common, especially as an abnormality in mammography. You don’t have to be too concerned unless you:
- Have a suspicious shape or layout of microcalcification (tiny specks of calcium deposits in your breast tissue) on your mammogram results.
- Notice continuous significant breast changes.
- Experience unexplained pain, itchiness, or redness in or around your breasts.
- See changes to the nipples (e.g., they become inverted or have discharge)
- Feel a lump in or around your breast.
- Have a family history of breast cancer.
Common reasons for a recall after a mammogram
Getting called back after a screening mammogram is common. It’s referred to as a recall and shouldn’t be cause for alarm. 6% of women who get mammograms are called back for more breast imaging. The American Cancer Society states that only 1 in 10 of such cases result in a breast cancer diagnosis. The most common reasons for a recall are:
- Baseline mammogram: This is the first mammogram you undergo. Your doctor may call you back for follow-up mammograms to obtain more images for an accurate diagnosis.
- Unclear images: This could be when the image doesn’t show all the breast tissue or if the breast was positioned differently compared to previous exams, making it difficult to identify changes.
- Additional testing: If your doctor notices any suspicious areas, developing asymmetry or significant dense breast tissue, they may request further testing to rule out any underlying conditions.
What are the next steps after finding asymmetry in a mammogram?
Now that your mammogram states you have breast asymmetry, what’s next? Here are a few steps you can take:
- Learn more about breast asymmetry.
You’ll be more at ease if you understand what it means and its relation to breast cancer. You can start by reading our more detailed article “Breast Asymmetry on a Mammogram: Should You Be Concerned?”
- Additional tests
A diagnostic mammogram is recommended in most cases. Your doctor may also recommend more tests like a breast MRI, ultrasound or biopsy for a more accurate diagnosis and to reduce your chance of developing breast cancer.
- Practice self-compassion
Beauty comes in all shapes and sizes, so try to focus on aspects of your appearance that make you feel confident.
- Find the right bra support.
Custom-made bras for asymmetric breasts not only offer the best support but will also boost your confidence. Our Signature Bra, for example, is designed to do just that and is specially made for women with uneven breasts.
Don’t panic!
Breast asymmetry, in most cases, is not a significant cause for concern. You'll know when you need medical attention as long as you stay informed and do regular check-ups. At Symmetrista, we’re all about empowering you with the right information and support to embrace your unique features and put your mind at ease.
Ready to feel fabulous? Check out Symmetrista today!