Breast calcifications are small deposits of calcium in the breast tissue. They are typically noncancerous. However, some forms can occasionally indicate breast cancer.

This article looks at the causes of breast calcifications, and we discuss what may happen if they show up on a screening test.

A woman shown from behind having a mammogram of her breasts.Share on Pinterest
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Calcifications are small calcium deposits that develop in the breasts. They do not cause symptoms, and a doctor cannot diagnose them from a routine breast check.

Instead, they typically appear as white dots on a mammogram, which is an X-ray of the breasts. Other breast scans, such as ultrasounds or MRI scans, do not show calcifications.

Calcifications are more likely to develop after menopause.

Most breast calcifications are benign. However, clusters of calcium deposits can suggest early breast cancer. Some research indicates 12.7–41.2% of women in screening programs with breast calcifications are brought back for additional clinical assessment as the only warning sign of cancer.

While calcifications do not develop into cancer, they can suggest an underlying process that is connected to breast cancer.

Two types of breast calcifications can appear on mammograms — macrocalcifications and microcalcifications. Some women have a mix of both.


Macrocalcifications appear as large white dots that occur randomly throughout the breast tissue. They are greater than 0.5 millimeters (mm) in diameter.

Macrocalcifications are very common, and doctors usually consider them to be benign. As a result, people with macrocalcifications in the breast usually require no follow-up testing.


Microcalcifications appear as tiny white specks or grains. Many cases of microcalcifications are benign. However, if they have certain characteristics, they may indicate an underlying cancerous process.

Doctors usually regard microcalcifications as suspicious and in need of further investigation if they have the following characteristics:

  • They are less than 0.5 mm in diameter.
  • They occur in clusters in one area of the breast.
  • They differ in size and shape.

Although this number is not definitive, a cluster generally consists of at least 3-5 calcifications. Loose clusters are more likely to be benign than compact clusters.

Calcifications outside the main breast tissue

Occasionally, a mammogram may show calcifications outside of the main breast tissue. These may appear to be on the skin or inside the blood vessels.

Those on the skin may be due to deodorant, lotions, or powder residue that causes white dots to appear on the X-ray results. For this reason, people should avoid applying any skin products before the screening.

Once the radiologist confirms the location as being outside of the breast tissue itself, then these types of calcifications require no further testing.

Calcifications can occur in the breast tissue as a result of:

Any of the above factors can cause breast calcifications to develop.

DCIS is the most common type of cancer diagnosed in people with breast calcifications.

A 2019 study also suggested a link between lifetime breastfeeding duration and the presence of microcalcification clusters. The report assessed the association of microcalcification clusters with multiple breast cancer risk factors.

Other factors that increase risk include:

  • a personal history of breast cancer
  • a family history of breast cancer
  • a genetic predisposition to breast cancer, such as having a BRCA1 and BRCA2 mutation

Eating calcium-rich foods does not cause breast calcifications.

If calcifications appear on a mammogram, the radiologist will decide if further investigation is necessary. Generally, they do not consider macrocalcifications suspicious. Standard sizes and shapes of calcifications are also less likely to require a follow-up.

However, if large calcifications occur in clusters or alongside microcalcifications, the radiologist may advise further testing.

If they consider the calcifications to be suspicious, they may:

  • perform another mammogram to view the calcifications more closely
  • check prior mammogram images to look for changes in calcification characteristics
  • refer the case to a doctor

A doctor may:

  • review the X-ray images and radiology report
  • take a biopsy to test the breast tissue for signs of cancer
  • recommend a breast MRI scan
  • recommend screening every 6 months to check for changes to the calcifications

People who have a history of breast cancer or are at a high risk of cancer development should see their doctor if calcifications appear on a mammogram. A doctor will consider these risk factors when deciding on further testing.

A breast biopsy involves removing a small piece of breast tissue to examine it closely. There are two types of biopsies to test breast calcifications.

Stereotactic core needle biopsy is when a doctor inserts a needle into the breast, using computer imaging, to remove a piece of calcification tissue under local anesthetic. A surgical biopsy is when a surgeon removes the abnormal tissue sample under local or general anesthetic and sends it to a lab for examination.

Doctors typically only perform a surgical biopsy if a core needle biopsy is unsuccessful or if the results are inconclusive.

Before undergoing a surgical biopsy, individuals should discuss scarring, anesthesia, or recovery concerns with their surgeon.

Benign calcifications do not require any treatment. However, if the calcifications are associated with another medical condition, such as mammary duct ectasia, a doctor will provide the person with more information on the condition and available treatments.

If the calcifications indicate breast cancer, the person will require treatment to stop the spread of cancer and kill the cancerous cells. The type of treatment a person will need depends on the type of breast cancer, its size and stage, and other factors.

Potential treatments for breast cancer include:

Breast calcifications can indicate early breast cancer, which highlights the importance of having regular screening mammograms. However, most calcifications are benign and do not need follow-up investigations or treatment.

If a radiologist considers the calcifications suspicious, they will perform another mammogram and may recommend a biopsy.

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