Understanding the Meaning of Breast Calcifications on Your Mammogram

Types and Patterns of Breast Calcifications and Their Causes

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Breast Calcifications on a Mammogram
What is the meaning of breast calcifications on a mammogram?. National Cancer Institute

If your doctor mentions that you have breast calcifications on your mammogram, you're likely frightened. What does this mean?


Breast calcifications are one of the findings that may be seen on your mammogram,  and are very common. In fact half of women over the age of 50 will have some type of calcifications on her mammogram. They appear as white dots on your mammogram and may or may not be worrisome for breast cancer, depending on the type, pattern, and arrangement of the calcifications.


Let's learn about the types of breast calcifications and what causes them. 


There are two types of breast calcifications, which often mean very different things. Instead of "macro" or "micro" your doctor may use to describe these different types such as small or large.


Macrocalcifications are large bits of calcium deposits found on a mammogram. They may be due to natural changes in a woman's breast, like hardening of her breast arteries. Macrocalcifications may also represent areas of inflammation from an old injury or breast trauma.

Macrocalcifications are not usually linked to breast cancer. According to the American Cancer Society, macrocalcifications occur in about 50 percent of women over the age of 50 and about 10 percent of women under the age of 50. 


Microcalcifications are tiny bits of calcium deposits that may be an early sign of breast cancer, although not always.

The pattern of microcalcifications in a woman's breast tissue helps a radiologist decide whether breast cancer could be present. 

Pattern and Shape 

The pattern and shape of microcalcifications is often different depending on whether the finding is benign or malignant. For example, eggshell calcifications or rim-like calcifications on a mammogram are usually benign, as are popcorn-like calcifications.

Benign means that the calcifications are not due to cancer. Calcifications arranged in a loose cluster are also more likely to be benign.

Suspicious findings may be described as irregular in size or shape (spiculated.) Changes such as linear rod-like calcifications are commonly seen in breast cancer, as are calcifications that vary in shape and size. Calcifications arranged in a tight cluster are also concerning for cancer. 

Benign (Non-Cancerous) Causes 

There are many different possible causes of breast calcifications, both those that are benign and those that suggest a malignancy. Some of the causes of breast calcifications unrelated to breast cancer include:

  • Scar tissue related to old breast injuries (dystrophic changes), leftover from prior breast cancer surgery (fat necrosis), or simply due to the natural wear and tear of the breasts
  • Mastitis or inflammation caused by a breast infection
  • Calcium collected inside a dilated milk duct
  • Calcium mixed with fluid in a benign breast cyst
  • Powders, ointments or deodorants deposit calcium on the skin (this is the reason that women are advised not to wear deodorant before their mammograms)
  • Radiation treatment for breast cancer
  • Calcification in the arteries within your breast

Next Steps

If your mammogram shows microcalcifications that are worrisome for breast cancer, a biopsy is recommended. A biopsy means that a small area of the suspicious breast tissue is removed and examined under a microscope for cancer cells. The most commonly performed procedure when calcifications are found is a  stereotactic breast core biopsy.

A biopsy is not always needed if there are microcalcifications — sometimes just close follow-up. It’s very important to do follow-up exams and tests to make sure that you get the best information on your health.

Being Your Own Advocate With Your Mammogram

Doctors do not always mention the word "calcifications" when talking to women about their mammograms. They may instead mention a "small abnormality." It's important to ask specifically what was found if you have an abnormal result. You should also ask for clarification if you are simply told that you have calcifications.

Don't be afraid to call your doctor or her nurse and ask for more information about the size or pattern of the calcifications. If you want to advocate for yourself it's important to have all of the pieces of the puzzle if you will. After learning about the descriptions of calcifications, also ask what the pattern is.


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