What are breast cysts?

Breast cysts are bubbles of fluid in your breast. They are like blisters. They are common in females aged 30 to 50 years. They are also common in females taking hormone replacement therapy. Cysts are not dangerous.

Breast cysts are benign (not cancer). They do not change to become cancer.

Breast cancer can happen in the same part of the breast as a cyst. But the cyst will not cause breast cancer.

What are the symptoms of breast cysts?

Breast cysts can feel tender if you press on them. The breast area around a cyst may also feel tender or painful. This can happen even if you can't feel a cyst.

Breast cysts can be more painful before your period (menstruation).

What causes breast cysts?

Fluid is always being made in your breast. After being made, the fluid is reabsorbed. This means the fluid goes back into your breast tissue.

Breast cysts can happen if more fluid is produced than reabsorbed. During a your menstrual cycle, breast cysts may form or get larger. Sometimes breast cysts happen when a milk duct becomes blocked.

Most cysts are tiny. They are only a few millimetres in diameter. They usually develop quickly. Then, they stay the same size.

You may have more than one cyst. Larger cysts can be felt when you examine your breasts. They can be either soft or firm. They should move easily in your breast.

It's not known why some people have more breast cysts than others.

It's important to know how your breasts normally feel. This can help you notice any changes quickly. Some breast lumps may not be cysts.

When should I see my doctor?

You need to see your doctor if:

• you find a new lump in your breast or armpit
• part of your breast feels thick or swollen
• the skin on your breast is dimpled, red or itchy
• your nipple is painful, pulled in or has fluid coming out of it
• there is redness or flaky skin on your breast or nipple
• the size and shape of your breast has changed
• your breast is painful all the time

How are breast cysts diagnosed?

Breast exam

Larger breast cysts can usually be felt by you or your doctor. However, your doctor will need to order imaging tests to know what is causing your lump(s).

Ultrasound or mammogram

Smaller cysts are often only found by an ultrasound or a mammogram.

An ultrasound helps your doctor see if your lump is solid or filled with fluid. Fluid filled lumps are usually cysts.

Breast biopsy

Sometimes your lump may be solid. Or it may have solid parts and fluid parts (a complex cyst). If this is the case your doctor may suggest another test called a biopsy. It's important to make sure that your lump is harmless.

How are breast cysts treated?

Breast cysts are harmless. They do not usually need to be treated.

Your doctor may also recommend draining a cyst if it's very large or painful.

Your doctor will use a very fine needle to drain the cyst. This may feel a bit uncomfortable. Any pain will not last for very long.

Draining a cyst usually only takes a couple of minutes for each cyst. The fluid inside the cyst may look clear or coloured. This is normal. It's nothing to worry about.

Draining your cyst will shrink it. Sometimes cysts come back. They are treated in the same way as the first cyst.

Resources and support

For more information about breast cysts and breast changes:

Download the Breast Cysts brochure from the Westmead Breast Cancer Institute.

Download the Breast Changes brochure from the National Breast Cancer Centre.

Download the Breast Cysts brochure from the Royal Women's Hospital (Victoria). Brochures in languages other than English are available.

Phone Breast Cancer Network Australia on 1800 500 258.

You can also call the healthdirect helpline on 1800 022 222 (known as NURSE-ON-CALL in Victoria). A registered nurse is available to speak with you 24 hours a day, 7 days a week.