Breast cysts

Cysts are fluid-filled bubbles, similar to blisters, in the breast tissue. 

Most cysts develop rapidly and then stay the same size. A small number shrink or continue to grow. Cysts are often too small to feel. However, on ultrasound they appear as a round clear shape with a distinct outline. Larger cysts can be felt in the breast tissue. They might be firm or soft. Often women have more than one cyst at a time.

Cysts are not harmful or dangerous, but they are sometimes uncomfortable or painful. Often women find that their cyst(s) get tender or enlarged in the days before their period. Pushing on cysts can also make them tender.

Researchers do not know what causes cysts. We do know that they are very common and can affect women of any age. Cysts are especially common in women between the ages of 45 and 50. They often appear with menopause, when a woman’s hormones are changing rapidly, and go away when menopause has finished. Women who take Hormone Replacement Therapy (HRT) often get breast cysts.

Cysts and cancer

For many women, their biggest concern about a cyst is that it is, or will become, cancer. Cysts are not cancers. They are no more likely to become cancerous than any other part of the breast. There is no evidence that cysts cause cancer. Having a cancer in the same area as a cyst is a coincidence.

Diagnosing and treating a cyst

A physical examination and an ultrasound will usually provide enough information for the doctor to diagnose a cyst.

If a cyst is large enough to feel, the doctor will usually offer to drain it using a needle. Although cysts are not dangerous, draining them removes the lump and often helps women to stop worrying. Doctors do not usually drain cysts that can be seen on ultrasound, but are too small to feel.

To drain a cyst, the doctor uses a needle to take the fluid out. This process is called Fine Needle Aspiration (FNA). The needle is finer than one used to take blood. FNA can be uncomfortable but usually is not painful. Women who have experienced some pain say that it passes quickly.

The fluid in a cyst might be clear or coloured (for example yellow, green, orange or black). This fluid is normal and it is not necessary to send it for testing.

Cysts can be drained at the clinic immediately. This only takes only a couple of minutes. The doctor might ask you to come back for a check-up in a couple of months.

What happens now?

Drained cysts shrink away to nothing. Usually there is no further action needed.

Many women have cysts that come back. These might be cysts that refill with fluid or they might be new cysts. Recurring cysts are not dangerous. They are treated the same way as the first cyst.

If you have a cyst drained and the lump refills within 24 hours, you should make an appointment to see the doctor again.

Your cyst does not put you at any increased risk of breast cancer. You should follow the recommendations for breast cancer screening for women of your age and family history.

All women need to be alert to any changes in their breasts that are not normal for them. If you have any change in your breast that is different to your usual hormonal changes, you should have it checked by your General Practitioner (GP).


For most women, having an unusual breast change is upsetting. It can bring up many different feelings and worries. It’s understandable to fear cancer. It’s also common to find tests stressful and invasive.

Most of the time women feel relieved to know that their breast change is due to a common condition that is not harmful or dangerous. Sometimes, however, women keep worrying about getting cancer. Some also find that their breast change affects how they feel about themselves, their sexuality or relationships.

If your breast change has had a negative impact on your life, it might help to share your feelings with supportive family members or friends. You could also get information or advice from your GP or a Women’s Health Nurse at your local community health centre. 


The Women’s does not accept any liability to any person for the information or advice (or use of such information or advice) which is provided on the Website or incorporated into it by reference. The Women’s provide this information on the understanding that all persons accessing it take responsibility for assessing its relevance and accuracy. Women are encouraged to discuss their health needs with a health practitioner. If you have concerns about your health, you should seek advice from your health care provider or if you require urgent care you should go to the nearest Emergency Dept.