Breast Density

Breast Density

At CommonSpirit Health, we understand that hearing you have dense breast tissue may be alarming, but you can take comfort in knowing that you’re far from alone. Between 40 and 50 percent of American women ages 40 to 74 years old have dense breast tissue.

Having dense breast tissue is not uncommon nor abnormal. For many women, breast density decreases with age. However dense breast tissue is associated with increased risk of breast cancer, and dense breast tissue can decrease the ability to accurately detect breast cancer.

Breast density refers to the ratio of fat compared to glandular/fibrous tissue in a woman’s breasts. Breast tissue is made up of milk glands, milk ducts, connective tissue (dense breast tissue) and fatty tissue (non-dense breast tissue).

When viewed on a mammogram, women with dense breasts have denser (connective) tissue, which appears white and opaque. Because breast tumors also appear white on a mammogram, the presence of dense breast tissue can make tumors and masses difficult to spot. In contrast, non-dense (fatty) breast tissue will appear dark and transparent on a mammogram.

There are four categories of breast density:

  • Almost entirely fatty
  • Scattered areas of fibroglandular density (indicating some scattered areas of density)
  • Heterogeneously dense (indicating some areas of non-dense tissue, but most the breast tissue is dense)
  • Extremely dense (nearly all the breast tissue is dense).

Having heterogeneously dense or extremely dense breast tissue can make it difficult to spot a small mass or other abnormality. A mammogram can tell you the category of your breast density.

Breast Density Chart

  • 3D mammography and automated whole breast ultrasound offers the most detailed images possible, which means fewer false-positive readings and callbacks for additional images. It also provides greater accuracy in locating an abnormality in the breast when compared to a conventional mammogram.
  • The American Cancer Society advises women with extremely dense breast tissue to talk with their doctors about more definitive imaging.
  • Automated Whole breast ultrasound (ABUS) uses sound waves to create 3D images of breast tissue, specifically developed and FDA-approved for women with dense breast tissue.
Patient receiving mammography services at Penrose Hospital.

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If your mammogram report shows you have dense breast tissue, talk with a doctor about what this means for your health and future breast screenings.