Breast Cysts

What is a breast cyst?

A breast cyst is a localised collection of fluid in the breast. Fluid is constantly being produced and reabsorbed in the milk ducts in the breast. When a duct becomes blocked or the amount of fluid produced is greater than the amount of fluid reabsorbed, fluid accumulates which causes cysts. Cysts can be single or multiple, and can come and go and vary in size during the menstrual cycle. 

Who gets breast cysts?  

Breast cysts are very common, with studies reporting cysts in up to 50% of women who attend breast clinics. They are most common in the 30 to 50 year age group. They usually disappear after menopause but in some women they can last through life (especially in women who take hormone replacement therapy).

What are the symptoms of breast cysts?

Breast lump

Large cysts can cause a palpable lump in the breast. The lump is usually smooth, soft and moves easily.

Breast pain 

Cysts are often tender, especially prior to a period. 

Do breast cysts cause cancer?

Breast cysts are not cancerous and having cysts does not significantly increase the risk of developing breast cancer. Women who frequently develop cysts may become complacent about new breast lumps, which may delay the diagnosis of breast cancer. It is important that every new breast lump be appropriately investigated.

How are breast cysts diagnosed?

Cysts are often seen on ultrasound or mammogram that has been performed for another reason. 

What is the treatment for breast cysts?

Most cysts cause no symptoms and have benign features on imaging - these do not require treatment. 

Cysts that are causing pain can be aspirated to reduce discomfort. 

Surgery is rarely recommended to remove cysts. Only cysts that recur after repeated aspiration or cysts that show worrying features on imaging or biopsy need to be removed.  

Can breast cysts come back?

Cysts can recur after aspirations or new cysts can form in the nearby breast tissue. A cyst that refills within a few weeks following aspiration may require more testing.