- What is a mammogram?
- Types of mammograms
- How is a mammogram done?
- Help with mammogram costs
- Regulation of mammography
- What does the doctor look for on a mammogram?
- Breast biopsy
- Mammogram reports – BI-RADS
- Mammograms in special circumstances
- Improving mammograms
- Other breast imaging tests
- Experimental and other breast imaging methods
- To learn more
What does the doctor look for on a mammogram?
A mammogram may show something suspicious, but by itself it can’t prove that an abnormal area is cancer. If a mammogram raises a suspicion of cancer, a tissue sample from the suspicious area must be removed and examined under the microscope to find out if it’s cancer. For detailed information on the types of biopsies and what you need to know, please see our document, For Women Facing a Breast Biopsy.
The doctor reading your mammogram will look for different types of changes.
Calcifications are tiny mineral deposits within the breast tissue. They look like small white spots on a mammogram. They may or may not be caused by cancer. There are 2 types of calcifications.
Macrocalcifications are coarse (larger) calcium deposits that are most likely due to changes in the breasts caused by aging of the breast arteries, old injuries, or inflammation. These deposits are related to non-cancerous conditions and do not require a biopsy. Macrocalcifications are found in about half the women over 50, and in 1 of 10 women under 50.
Microcalcifications are tiny specks of calcium in the breast. They may show up alone or in clusters. Microcalcifications seen on a mammogram are of more concern than macrocalcifications, but they do not always mean that cancer is present. The shape and layout of microcalcifications help the radiologist judge how likely it is that cancer is present.
In most cases, the presence of microcalcifications does not mean a biopsy is needed. But if the microcalcifications have a suspicious look and pattern, a biopsy will be recommended. (During a biopsy, the doctor removes a small piece of the suspicious area to be looked at under a microscope. A biopsy is the only way to tell if cancer is really present.)
A mass or cyst
A mass, with or without calcifications, is another important change seen on a mammogram. Masses are areas that look abnormal and they can be many things, including cysts (non-cancerous, fluid-filled sacs) and non-cancerous solid tumors (such as fibroadenomas).
Cysts can be simple fluid-filled sacs (known as simple cysts) or can be partially solid (known as complex cysts). Simple cysts are benign (not cancer) and don’t need to be biopsied. Any other type of mass (such as a complex cyst or a solid tumor) might need to be biopsied to be sure it isn’t cancer.
- cyst and a tumor can feel the same on a physical exam. They can also look the same on a mammogram. To confirm that a mass is really a cyst, a breast ultrasound is often done. Another option is to remove (aspirate) the fluid from the cyst with a thin, hollow needle.
- a mass is not a simple cyst (that is, if it’s at least partly solid), more imaging tests may be needed. Some masses can be watched with regular mammograms, while others may need a biopsy. The size, shape, and margins (edges) of the mass may help the radiologist determine if cancer is likely to be present.
Having your prior mammograms available for the radiologist is very important. They can help show that a mass or calcification has not changed for many years. This would mean that it’s likely not cancer and a biopsy is not needed.
Your mammogram report may also contain an assessment of breast density or state that you have dense breasts. Breast density is based on how much of your breast is made up fatty tissue vs. how much is made up of fibrous and glandular tissue.
Dense breasts are not abnormal, but they are linked to a higher risk of breast cancer. Although dense breast tissue can make it harder to find cancers on a mammogram, at this time, experts do not agree what other tests, if any, should be done in addition to mammograms in women with dense breasts who aren’t in a high-risk group (based on gene mutations, a strong family history of breast cancer, or other factors).
Last Medical Review: 12/17/2012
Last Revised: 02/07/2013