Breast calcifications

Breast calcifications are small spots (deposits) of calcium in the breast. They are usually harmless.

What are breast calcifications?

Breast calcifications are small spots of calcium in the breast. These are called deposits. They do not cause any symptoms and you cannot feel them. They are usually found during a routine mammogram.

Calcifications are common. In most cases they are harmless. There are 2 types:

  • macrocalcifications
  • microcalcifications.

Macrocalcifications (benign coarse calcifications)

These are areas of calcium that look like big white dots or dashes on a mammogram.

Macrocalcifications are sometimes called benign coarse calcifications. They are harmless. They can develop naturally as you get older. They are not linked to cancer and do not need treatment or monitoring.

Macrocalcifications can develop at any age. But they are more common after the menopause.

They may be caused by:

  • calcium deposits in a cyst or in milk ducts as you get older
  • previous injuries to the breast
  • inflammation.

Calcium in the diet does not cause calcifications.


These are tiny calcium deposits that show as small white dots on a mammogram. They are usually found in an area of the breast where cells are being replaced more quickly than normal.

Microcalcifications are not usually linked to cancer. But a group of them in 1 area of the breast (a cluster) may be a sign of:

  • pre-cancerous changes
  • early breast cancer.

What if a mammogram shows breast calcifications?

If your mammogram shows calcifications, a doctor specialising in reading x-rays and scans will assess them. This doctor is called a radiologist. They will look at the size, shape and pattern of the calcifications. They will decide if you need any further tests.

If the mammogram shows macrocalcifications only, you will not need any further tests or treatment.

If the mammogram shows microcalcifications, you will usually have a magnification mammogram of the affected area. If the results of this show the changes are clearly not cancer, you will not need any more tests.

If the results are not clear, your doctor will suggest a biopsy. This is when a small piece of tissue is removed from the breast. You may have a biopsy with a mammogram to help guide the biopsy. This is called a stereotactic biopsy.

After a biopsy, a doctor called a pathologist looks at the removed tissue under a microscope. This gives more information to help doctors make a diagnosis.

Biopsy results

A biopsy shows whether microcalcifications are non-cancerous (benign) or cancerous (malignant). Most microcalcifications are benign, and you will not need any treatment.

If there are cancer cells, it is usually a non-invasive breast cancer called ductal carcinoma in situ (DCIS), or a very small, early breast cancer. These can both be treated successfully.

Your feelings

If you are told you have breast calcifications and need further tests, it is natural to feel worried. But it is important to remember most breast calcifications are not a sign of cancer.

If the biopsy results show there is an early breast cancer, a surgeon or specialist nurse will explain more about it. They will talk to you about the treatment you need and give you support to help you cope.

If you have any concerns, talk to the doctor or specialist nurse at the clinic. 

Macmillan is also here to support you. If you would like to talk, you can:

About our information

  • Reviewers

    This information has been written, revised and edited by Macmillan Cancer Support’s Cancer Information Development team. It has been reviewed by expert medical and health professionals and people living with cancer. It has been approved by Dr Rebecca Roylance, Consultant Medical Oncologist and Professor Mike Dixon, Professor of Surgery and Consultant Breast Surgeon.

    Our cancer information has been awarded the PIF TICK. Created by the Patient Information Forum, this quality mark shows we meet PIF’s 10 criteria for trustworthy health information.

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We want everyone affected by cancer to feel our information is written for them.

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Date reviewed

Reviewed: 01 October 2023
Next review: 01 October 2026
Trusted Information Creator - Patient Information Forum
Trusted Information Creator - Patient Information Forum

Our cancer information meets the PIF TICK quality mark.

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