Changes that can be seen on a mammogram

Breasts are made up of fatty tissue and denser fibrous and glandular tissue. The amount of each varies from person to person.

Dense breast tissue shows up white on a mammogram. Breast cancer also appears white, which can make cancer harder to see in dense breasts.

Breast density is usually grouped into four grades:

• Category A: Mostly non-dense (fatty) tissue. About 1 in 10 women have this.
• Category B: Some areas of dense tissue. About 4 in 10 women have this.
• Category C: Around half to three-quarters of tissue is dense, sometimes described as moderate density. About 4 in 10 women have this.
• Category D: The breast tissue is extremely dense. About 1 in 10 women have this.

What should I do if I’ve been told I have dense breasts?

If you have an average risk of breast cancer, BreastScreen Aotearoa recommends you have two-yearly mammograms.

If you have a strong family history of breast cancer or an inherited genetic change that increases your risk, such as the BRCA 1 or 2 gene mutation, talk to a GP about the screening that’s right for you. They may refer you to a breast specialist or recommend an individual screening plan.

Find out more about breast density: Watch our webinar on breast density to learn more about why it’s important, how it’s measured, and how it might affect a breast cancer diagnosis. You can also read more about how breast density affects mammography here.

Duct ectasia is a non-cancerous breast condition that happens when one or more of the milk ducts behind the nipple become wider. 

It becomes more common as you get older, and may cause:

• Nipple discharge, which can be thick or watery and may be green, black or sometimes bloodstained
• A lump or thickening behind the nipple
• The nipple to turn inwards.

These symptoms can also have other causes, so it’s important to get them checked by a GP. A doctor may recommend tests like a mammogram or ultrasound to find out what is causing the change.

Duct ectasia is more common in people who smoke, this is likely because smoking irritates and inflames the milk ducts.

Despite its name, a radial scar isn’t actually a scar. It’s an area of changed breast tissue that is usually found on a mammogram rather than felt as a lump.

A radial scar can look similar to breast cancer on a mammogram, so further tests are usually needed. This may include a core biopsy, where a small sample of breast tissue is taken and examined.

You may be referred to a breast specialist to discuss whether the area needs to be removed or monitored.

Sclerosing adenosis is a non-cancerous condition where there is extra growth of tissue in the milk-producing glands of the breast. 

It often causes no symptoms and may be found on a mammogram. Because it can sometimes look similar to breast cancer, further tests may be needed to confirm what it is. 

Sclerosing adenosis usually doesn’t need treatment. It is associated with a small increase in the risk of developing breast cancer.

An intraductal papilloma is a small, non-cancerous growth inside one of the breast’s milk ducts. It’s most common in women aged 35-55.

It may:

• Cause a lump near the nipple
• Cause clear or bloodstained nipple discharge
• Be found on a mammogram without causing any symptoms.

If an intraductal papilloma is suspected, you may be referred to a breast clinic for further tests. 

A single papilloma with no abnormal cells doesn’t increase your risk of breast cancer. People who have multiple papillomas have a slightly higher risk of developing breast cancer and may need regular follow-up.

Benign breast calcifications are tiny deposits of calcium in the breast tissue. They’re common and usually harmless.

Calcifications are too small to feel and are usually found on a mammogram. They aren’t caused by the amount of calcium in your diet.

Most calcifications aren’t breast cancer. There can be different causes, such as:

• Natural ageing of breast tissue
• Previous infection
• Trauma
• Surgery
• Cysts
• Fibroadenomas
• Radiation therapy.

When they’re found, a radiologist looks at their size, shape and pattern to decide whether they need further investigation.

If the calcification looks harmless, you usually won’t need any further tests or treatment. If their appearance is uncertain, you may need additional mammograms or a biopsy to check them more closely.

A fibroadenoma is a common, non-cancerous breast lump. It can be found when you notice a lump yourself or during a mammogram or ultrasound. 

Fibroadenomas are particularly common in younger women. They can change in size in response to hormones, and you may have more than one. 

If a fibroadenoma is suspected, you may need a biopsy to confirm what the lump is. 

Most fibroadenomas don’t need treatment and may get smaller over time. If yours gets bigger, becomes painful or is causing you concern, talk to a GP about it. You may get a referral to a breast specialist to get it removed.