Breast Health

Fibroglandular Density in Breasts

Dense Breast Tissue May Make Detecting Cancer Harder

Dense breast tissue, or fibroglandular density, can make it harder to detect breast cancer, putting women with dense breasts at a higher risk. A mammogram can determine if you have dense breast tissue, giving you and your doctor the information you need to make decisions about your breast health.


Learn About Your Breast Density:
Schedule a Mammogram Today

An annual mammogram screening is the best way to detect cancer early, when it is easiest to treat. Use our convenient online scheduling tool to book your mammogram appointment today or call 216-844-2778.

Schedule Online

What is Dense Breast Tissue?

Breasts are made up of a mixture of fibrous and glandular tissue and fatty tissues. A woman’s breasts are considered dense if she has a lot of fibrous or glandular tissue, but not much fat. Density may decrease with age, but there is little, if any, change in most women.

Radiologists classify breast density using a four-level density scale, as determined by a mammogram:

  • Category A: Almost entirely fatty
  • Category B: Scattered areas of fibroglandular density
  • Category C: Heterogeneously dense
  • Category D: Extremely dense
Breast Density Almost Entirely Fatty
Category A: Almost entirely fatty
Breast Density Scattered Areas of Fibroglandular Density
Category B: Scattered areas of fibroglandular density
Breast Density Heterogeneously Dense
Category C: Heterogeneously dense
Breast Density Extremely Dense
Category D: Extremely dense
Breast Density Handout Thumbnail
Download Breast Density: Breast Cancer Screening

In the U.S., breast density is distributed as follows:

  • 10 percent of women have almost entirely fatty breasts
  • 10 percent have extremely dense breasts
  • 80 percent are classified into one of the two middle categories
Breast Density Distribution

Why Is Fibroglandular Density Important?

Having dense breast tissue may increase your chance of getting breast cancer. Dense breasts also make it more difficult for doctors to spot cancer on mammograms. Dense tissue appears white on a mammogram; lumps, both benign and cancerous, also appear white. So mammograms can be less accurate in women with dense breast tissue.

Determining Breast Density

Fibroglandular density is determined by the radiologist who reads a mammogram. The radiologist assigns each mammogram to one of the four categories of breast density. If your mammogram shows that you have heterogeneously dense or extremely dense breast tissue, you will receive a letter notifying you that you have dense breasts. You can speak to your primary care physician about your risk and your breast cancer screening options.

Mammograms and Other Tests for Dense Breasts

Women with dense breasts should continue to receive a mammogram every year. Even though it may be harder to detect, a mammogram is still the best way to detect breast cancer in dense breasts. Additional tests if needed, may include:

  • Tomosynthesis (3-D mammography)
  • Breast ultrasound
  • Breast magnetic resonance imaging (MRI)

Screening Tests for Dense Breasts

Learn About Your Breast Density: Schedule a Mammogram Today

An annual mammogram screening is the best way to detect cancer early, when it is easiest to treat. Use our convenient online scheduling tool to book your mammogram appointment today or call 216-844-2778.