What are breast cysts?

Breast cysts are a benign (not cancer) condition. They are one of the most common causes of a breast lump, and can develop in either one or both breasts.

breast diagram illustration checking

It’s thought that breast cysts develop naturally as the breast changes with age, due to normal changes in hormone levels. It’s common to have more than one cyst.

Breasts are made up of lobules (milk-producing glands) and ducts (tubes that carry milk to the nipple), which are surrounded by glandular, fibrous and fatty tissue. Sometimes, fluid-filled sacs develop in the breast tissue; these are breast cysts.

Although you can develop breast cysts at any age, they are most common in women over 35. They develop more often as women get closer to the menopause and usually stop once a woman has been through the menopause. Women who use hormone replacement therapy (HRT) after the menopause may also develop cysts.

Breast cysts can feel soft or hard and can be any size, ranging from a few millimetres to several centimetres. They can develop quickly and anywhere in the breast. For some people, cysts can feel uncomfortable and even painful. Before a period, cysts may become larger and feel sore and tender. However, many women can have cysts and not be able to feel them at all.

Although much more common in women, men can also get breast cysts.

How are they found?

Cysts usually become noticeable as a lump in the breast or are found by chance during a routine screening mammogram (breast x-ray) or while having investigations at a breast clinic for another reason.

If you see your GP (local doctor) because you have found a lump, they will sometimes be able to say whether it feels like a cyst. However, they are still likely to refer you to a breast clinic where you’ll be seen by specialist doctors or nurses and have some tests.

At the breast clinic you will have a breast examination. You may also have a mammogram and/or an ultrasound scan (which uses high-frequency sound waves to produce an image of the breast).

If you are under 40 you’re more likely to have an ultrasound scan only. This is because younger women’s breast tissue can be dense, which can make the x-ray image less clear, making normal changes or benign conditions harder to find.

If the lump can be easily felt, your specialist may put a fine needle into it and draw off the fluid to confirm that it’s a fluid-filled cyst.

Please call our free Helpline if you’d like more information about any tests you may be having, or visit our referral to a breast clinic page.

Treatment and follow-up

If you do have a breast cyst or cysts, you won’t usually need any treatment or follow-up. Most cysts go away by themselves and are nothing to worry about.

If the cyst is large or causing discomfort, your specialist may draw off the fluid using a fine needle and syringe. Sometimes this is done using ultrasound to help find the cyst. The fluid drawn off from the cyst can vary in colour and range from clear to very dark. It will only be sent to a laboratory for testing if the fluid is blood-stained.

Once the fluid has been drawn off, the cyst usually disappears. You might feel some discomfort as the fluid is being drawn off, and the area may feel bruised and tender for some days afterwards. If so, taking pain relief like paracetamol should help.

Breast cysts can come back, or you may develop new cysts. The treatment for cysts is usually the same each time.

What this means for you

You may feel anxious about having a breast cyst or cysts. Even though you may be relieved that it’s a benign condition, you may still worry about breast cancer. You should also see your GP if you think your cyst has come back or you think you have developed a new one.

Having a breast cyst or cysts does not increase your risk of developing breast cancer. However, it’s still important to be breast aware and go back to your GP if you notice any changes in your breasts, regardless of how soon these occur after your diagnosis.

Last reviewed: January 2016
Next planned review begins 2019

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