Table of ContentsView AllTable of ContentsWhat Is Asymmetry?Causes of Breast AsymmetryIs It a Sign of Cancer?Next StepsOutlook
Table of ContentsView All
View All
Table of Contents
What Is Asymmetry?
Causes of Breast Asymmetry
Is It a Sign of Cancer?
Next Steps
Outlook
Breast asymmetryon amammogramreport means that part of one breast looks different from the other at the same site or part of the breast.With focal asymmetry, it means the area is identified in two or more views of the mammogram, often due to benign (not harmful) changes.Yet a significant variation or sudden change in aspects, such as density, could indicate a problem. Developing asymmetry can be a more concerning finding because it represents a change from previous images. Your healthcare provider will discuss the results and further tests with you.Learn more aboutbreast asymmetry, its causes, how it relates to cancer, testing, and more.Hero Images / Getty ImagesWhat Is Asymmetry?Asymmetry results on a mammogram indicate that the image shows something different on one breast when compared to the same site of the other breast. Tissue within the same breast also is evaluated.Types of breast asymmetry seen on a mammogram include:Focal asymmetry: A difference in the breast is seen on two or more mammogram images. This is typically a small, localized site with an assessment based on the same location in the other breast. It is seen in about 21% of all mammograms and is not typically cancer.One-view asymmetry: A focal asymmetry, it’s seen in only one view of a mammogram. It occurs up to 20.5% of the time, often due to benignfibroglandular(density) changes.Global asymmetry: More breast tissue is involved in one breast or one area of a breast than seen in focal asymmetry. This occurs in about 3% of mammograms and is considered a normal variant.Developing asymmetry: Focal asymmetry appears togrow or changecompared to previous tests. It occurs in up to 4.4% of cases and can be due to benign or malignant causes.When breast asymmetry is detected, additional testing may be recommended.An asymmetry is present in about 6% of breast cancers detected on mammogram screening, but it also is a common reason forrecall teststhat turn out to be false alarms with no cancer present.A study of 201 people with four different types of breast asymmetry found six cases of an invasive breast cancer and two cases ofductal carcinoma in situ(DCIS), with benign causes in all other cases.Focal asymmetry accounted for six of the eight, with developing symmetry in the other breast cancer cases.Normal and Abnormal Mammogram ImagesNational Cancer InstituteCauses of Breast AsymmetryBenign causes of breast asymmetry on mammogram include the following:Fibrocysticchanges:Cysts filled with fluid and scar tissue in the area of the cystsDensestromal fibrosis: The connective tissue in that area of the breast is denser than it is in other areasPseudoangiomatous stromal hyperplasia: A lump of non-cancerous cells that grows in the breastBreast Asymmetry CausesGrowths, such as fibroids orcystsDense breast tissueLumps or massesIs Asymmetry a Sign of Cancer?It is unclear how breast asymmetry impacts cancer risk, and it may depend on the cause of breast asymmetry. For example, fibrocystic changes do not increase cancer risk, nor does pseudoangiomatous stromal hyperplasia.Stromal fibrosis can increase the risk of breast cancer and may be associated with inaccurate biopsies.This can happen when non-cancerous stromal fibrosis is located next to cancerous cells; abiopsysample containing the non-cancerous stromal fibrosis is taken without catching any cancerous cells.While breast asymmetry is not usually indicative ofcancer, medical professionals may recommendtestingto be sure.National Cancer InstituteWhat Happens if Your Mammogram Shows Asymmetry?When breast asymmetry is found on a mammogram, additionalscreening testsare usually recommended to rule out breast cancer.Further testing should not be a major reason for concern; many people with breasts who have a screening mammogram are asked to undergo additional testing, and less than 10% of them receive abreast cancer diagnosis.A diagnostic mammogram is often the next step. It is similar to a screening mammogram but with additional images of the asymmetric area.For a more accurate result, 3D tomosynthesis, which uses X-ray technology like a mammogram, can take images from more angles.Types of Additional Screening for Breast AsymmetryDigital breast tomosynthesis(3D mammogram)BiopsyDiagnostic mammogramMagnetic resonance imaging(MRI)UltrasoundThe type of follow-up testing also depends on what is found on the screening mammogram:Focal symmetry: Six-month follow-up imaging for findings without suspicious featuresOne-view symmetry: Same six-month approach as focal symmetry findingsGlobal asymmetry: Likely does not require follow-up in the absence of suspicious featuresDeveloping asymmetry: More concerning due to changes and may require biopsySometimes a combination of additional tests is recommended.OutlookBreast asymmetry is usually entirely normal and does not indicate an increased risk for cancer.However, it is important to see your healthcare provider for an evaluation and follow through with any recommended testing.If the initial mammogram result of breast asymmetry does lead to a breast cancer diagnosis, it is a treatable condition with highsurvival rates.When Can I Say I Am a Breast Cancer Survivor?SummaryBreast asymmetry means that a specific breast area appears different from the tissue at the same site on the other breast. When found on a mammogram, it can be but usually is not a sign of cancer.Even so, additional testing, such as a diagnostic mammogram or 3D tomosynthesis, may be recommended to ensure breast cancer is not overlooked. Talk with your healthcare provider about your concerns, any symptoms, or the tests needed to evaluate your breast asymmetry.
Breast asymmetryon amammogramreport means that part of one breast looks different from the other at the same site or part of the breast.With focal asymmetry, it means the area is identified in two or more views of the mammogram, often due to benign (not harmful) changes.
Yet a significant variation or sudden change in aspects, such as density, could indicate a problem. Developing asymmetry can be a more concerning finding because it represents a change from previous images. Your healthcare provider will discuss the results and further tests with you.
Learn more aboutbreast asymmetry, its causes, how it relates to cancer, testing, and more.
Hero Images / Getty Images
Asymmetry results on a mammogram indicate that the image shows something different on one breast when compared to the same site of the other breast. Tissue within the same breast also is evaluated.
Types of breast asymmetry seen on a mammogram include:
When breast asymmetry is detected, additional testing may be recommended.An asymmetry is present in about 6% of breast cancers detected on mammogram screening, but it also is a common reason forrecall teststhat turn out to be false alarms with no cancer present.
A study of 201 people with four different types of breast asymmetry found six cases of an invasive breast cancer and two cases ofductal carcinoma in situ(DCIS), with benign causes in all other cases.Focal asymmetry accounted for six of the eight, with developing symmetry in the other breast cancer cases.
Normal and Abnormal Mammogram Images
National Cancer Institute
Benign causes of breast asymmetry on mammogram include the following:
Breast Asymmetry CausesGrowths, such as fibroids orcystsDense breast tissueLumps or masses
Breast Asymmetry Causes
Growths, such as fibroids orcystsDense breast tissueLumps or masses
Is Asymmetry a Sign of Cancer?
It is unclear how breast asymmetry impacts cancer risk, and it may depend on the cause of breast asymmetry. For example, fibrocystic changes do not increase cancer risk, nor does pseudoangiomatous stromal hyperplasia.
Stromal fibrosis can increase the risk of breast cancer and may be associated with inaccurate biopsies.This can happen when non-cancerous stromal fibrosis is located next to cancerous cells; abiopsysample containing the non-cancerous stromal fibrosis is taken without catching any cancerous cells.
While breast asymmetry is not usually indicative ofcancer, medical professionals may recommendtestingto be sure.
What Happens if Your Mammogram Shows Asymmetry?
When breast asymmetry is found on a mammogram, additionalscreening testsare usually recommended to rule out breast cancer.Further testing should not be a major reason for concern; many people with breasts who have a screening mammogram are asked to undergo additional testing, and less than 10% of them receive abreast cancer diagnosis.
A diagnostic mammogram is often the next step. It is similar to a screening mammogram but with additional images of the asymmetric area.For a more accurate result, 3D tomosynthesis, which uses X-ray technology like a mammogram, can take images from more angles.
Types of Additional Screening for Breast AsymmetryDigital breast tomosynthesis(3D mammogram)BiopsyDiagnostic mammogramMagnetic resonance imaging(MRI)Ultrasound
Types of Additional Screening for Breast Asymmetry
Digital breast tomosynthesis(3D mammogram)BiopsyDiagnostic mammogramMagnetic resonance imaging(MRI)Ultrasound
The type of follow-up testing also depends on what is found on the screening mammogram:
Sometimes a combination of additional tests is recommended.
Breast asymmetry is usually entirely normal and does not indicate an increased risk for cancer.However, it is important to see your healthcare provider for an evaluation and follow through with any recommended testing.
If the initial mammogram result of breast asymmetry does lead to a breast cancer diagnosis, it is a treatable condition with highsurvival rates.
When Can I Say I Am a Breast Cancer Survivor?
Summary
Breast asymmetry means that a specific breast area appears different from the tissue at the same site on the other breast. When found on a mammogram, it can be but usually is not a sign of cancer.
Even so, additional testing, such as a diagnostic mammogram or 3D tomosynthesis, may be recommended to ensure breast cancer is not overlooked. Talk with your healthcare provider about your concerns, any symptoms, or the tests needed to evaluate your breast asymmetry.
13 SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Johns Hopkins Medicine.Understanding your mammogram report.Gurando AV, Babkina TM, Dykan IM, Kozarenko TM, Gurando VR, Telniy VV.DIGITAL BREAST TOMOSYNTHESIS AND FULL-FIELD DIGITAL MAMMOGRAPHY IN BREAST CANCER DETECTION ASSOCIATED WITH FOUR ASYMMETRY TYPES.Wiad Lek. 2021;74(4):842-848. PMID: 34155990American Academy of Family Physicians.Is asymmetric breast tissue a sign of malignancy?American Cancer Society.Fibrocystic changes in the breast.Estes A, Cao L, Miller ME.Pseudoangiomatous stromal hyperplasia: overview and clinical management.Annals of Breast Surgery. 2020;4(0). doi:10.21037/abs-20-86Malik N, Lad S, Seely JM, Schweitzer ME.Underestimation of malignancy in biopsy-proven cases of stromal fibrosis.BJR. 2014;87(1039):20140182. doi:10.1259/bjr.20140182American Cancer Society.What does the doctor look for on a mammogram?American Cancer Society.Getting called back after a mammogram.Mokhtar O, Abd elsalam S, Gamal G, et al.3d digital breast tomosynthesis versus us in evaluating breast asymmetries.Egyptian Journal of Radiology and Nuclear Medicine. 2020;51(1):110. doi:10.1186/s43055-020-00196-0UCLA Health.Breast Asymmetry.University of Utah Health.My breasts are different sizes - am I normal?Kayar R, Çilengiroğlu ÖV.Breast volume asymmetry value, ratio, and cancer risk.Breast Cancer. 2015;987-92. doi:10.4137/BCBCR.S32789American Cancer Society.Survival rates for breast cancer.
13 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Johns Hopkins Medicine.Understanding your mammogram report.Gurando AV, Babkina TM, Dykan IM, Kozarenko TM, Gurando VR, Telniy VV.DIGITAL BREAST TOMOSYNTHESIS AND FULL-FIELD DIGITAL MAMMOGRAPHY IN BREAST CANCER DETECTION ASSOCIATED WITH FOUR ASYMMETRY TYPES.Wiad Lek. 2021;74(4):842-848. PMID: 34155990American Academy of Family Physicians.Is asymmetric breast tissue a sign of malignancy?American Cancer Society.Fibrocystic changes in the breast.Estes A, Cao L, Miller ME.Pseudoangiomatous stromal hyperplasia: overview and clinical management.Annals of Breast Surgery. 2020;4(0). doi:10.21037/abs-20-86Malik N, Lad S, Seely JM, Schweitzer ME.Underestimation of malignancy in biopsy-proven cases of stromal fibrosis.BJR. 2014;87(1039):20140182. doi:10.1259/bjr.20140182American Cancer Society.What does the doctor look for on a mammogram?American Cancer Society.Getting called back after a mammogram.Mokhtar O, Abd elsalam S, Gamal G, et al.3d digital breast tomosynthesis versus us in evaluating breast asymmetries.Egyptian Journal of Radiology and Nuclear Medicine. 2020;51(1):110. doi:10.1186/s43055-020-00196-0UCLA Health.Breast Asymmetry.University of Utah Health.My breasts are different sizes - am I normal?Kayar R, Çilengiroğlu ÖV.Breast volume asymmetry value, ratio, and cancer risk.Breast Cancer. 2015;987-92. doi:10.4137/BCBCR.S32789American Cancer Society.Survival rates for breast cancer.
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
Johns Hopkins Medicine.Understanding your mammogram report.Gurando AV, Babkina TM, Dykan IM, Kozarenko TM, Gurando VR, Telniy VV.DIGITAL BREAST TOMOSYNTHESIS AND FULL-FIELD DIGITAL MAMMOGRAPHY IN BREAST CANCER DETECTION ASSOCIATED WITH FOUR ASYMMETRY TYPES.Wiad Lek. 2021;74(4):842-848. PMID: 34155990American Academy of Family Physicians.Is asymmetric breast tissue a sign of malignancy?American Cancer Society.Fibrocystic changes in the breast.Estes A, Cao L, Miller ME.Pseudoangiomatous stromal hyperplasia: overview and clinical management.Annals of Breast Surgery. 2020;4(0). doi:10.21037/abs-20-86Malik N, Lad S, Seely JM, Schweitzer ME.Underestimation of malignancy in biopsy-proven cases of stromal fibrosis.BJR. 2014;87(1039):20140182. doi:10.1259/bjr.20140182American Cancer Society.What does the doctor look for on a mammogram?American Cancer Society.Getting called back after a mammogram.Mokhtar O, Abd elsalam S, Gamal G, et al.3d digital breast tomosynthesis versus us in evaluating breast asymmetries.Egyptian Journal of Radiology and Nuclear Medicine. 2020;51(1):110. doi:10.1186/s43055-020-00196-0UCLA Health.Breast Asymmetry.University of Utah Health.My breasts are different sizes - am I normal?Kayar R, Çilengiroğlu ÖV.Breast volume asymmetry value, ratio, and cancer risk.Breast Cancer. 2015;987-92. doi:10.4137/BCBCR.S32789American Cancer Society.Survival rates for breast cancer.
Johns Hopkins Medicine.Understanding your mammogram report.
Gurando AV, Babkina TM, Dykan IM, Kozarenko TM, Gurando VR, Telniy VV.DIGITAL BREAST TOMOSYNTHESIS AND FULL-FIELD DIGITAL MAMMOGRAPHY IN BREAST CANCER DETECTION ASSOCIATED WITH FOUR ASYMMETRY TYPES.Wiad Lek. 2021;74(4):842-848. PMID: 34155990
American Academy of Family Physicians.Is asymmetric breast tissue a sign of malignancy?
American Cancer Society.Fibrocystic changes in the breast.
Estes A, Cao L, Miller ME.Pseudoangiomatous stromal hyperplasia: overview and clinical management.Annals of Breast Surgery. 2020;4(0). doi:10.21037/abs-20-86
Malik N, Lad S, Seely JM, Schweitzer ME.Underestimation of malignancy in biopsy-proven cases of stromal fibrosis.BJR. 2014;87(1039):20140182. doi:10.1259/bjr.20140182
American Cancer Society.What does the doctor look for on a mammogram?
American Cancer Society.Getting called back after a mammogram.
Mokhtar O, Abd elsalam S, Gamal G, et al.3d digital breast tomosynthesis versus us in evaluating breast asymmetries.Egyptian Journal of Radiology and Nuclear Medicine. 2020;51(1):110. doi:10.1186/s43055-020-00196-0
UCLA Health.Breast Asymmetry.
University of Utah Health.My breasts are different sizes - am I normal?
Kayar R, Çilengiroğlu ÖV.Breast volume asymmetry value, ratio, and cancer risk.Breast Cancer. 2015;987-92. doi:10.4137/BCBCR.S32789
American Cancer Society.Survival rates for breast cancer.
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