What is a breast cyst?
A breast cyst is a noncancerous (benign), fluid-filled sac in the breast. It occurs when fluid fills an empty milk gland. Some cysts are too small to feel, while others grow up to several inches — large enough to make you uncomfortable. Clusters of cysts can form in one breast or both.
How common are breast cysts?
Breast cysts are common, especially for women in their later childbearing years. It’s easy to mistake them for a lump that could be cancer. About a quarter of breast masses turn out to be cysts.
Who gets breast cysts?
You’re more likely to get breast cysts if you are:
Symptoms and Causes
What causes breast cysts?
The exact cause of breast cysts is still unknown. Experts believe hormonal fluctuations may cause them to form. Breast cysts don’t usually develop in women after menopause, when estrogen levels taper off.
What are the symptoms of a breast cyst?
If you have a breast cyst, you may feel a lump that’s:
- Soft or hard.
- Round and smooth.
- Painful, especially before your menstrual cycle.
- Easily movable under the skin.
Diagnosis and Tests
How are breast cysts diagnosed?
Doctors often find breast cysts during routine mammograms that screen for breast cancer. But you may also discover a large breast cyst on your own.
What are the different types of breast cysts?
There are three types of breast cysts:
- Simple breast cyst: Filled entirely with fluid, simple cysts are always noncancerous.
- Complicated breast cyst: A complicated cyst has some solid fragments floating in the fluid. Your healthcare provider may want to perform a breast cyst aspiration or needle biopsy (withdrawing fluid with a needle for analysis).
- Complex breast cyst: This type of cyst is worrisome because it appears to have some solid tissue, which could be cancerous. If you have this type of cyst, your healthcare provider will do a needle biopsy.
Can a breast cyst be cancerous?
It’s rare, but not impossible, for a breast cyst to contain cancerous cells. Complex breast cysts are the most concerning.
How is a breast cyst aspiration performed?
During needle biopsy (also called an aspiration), a healthcare provider inserts a hollow needle into the cyst. The cyst collapses when the needle removes fluid from it. You may have some bruising and tenderness afterward.
Management and Treatment
How are breast cysts treated?
In most cases, you don’t need treatment. Simple breast cysts don’t cause any harm and sometimes even go away on their own.
If the cyst is uncomfortable, your healthcare provider can drain the fluid from it with a needle biopsy. However, the fluid could come back. If it returns and continues to be painful, you may need surgery to remove it.
For complicated or complex breast cysts, you may need more frequent checkups to keep tabs on any changes.
How do I prevent breast cysts?
You can’t prevent breast cysts. But regular self-exams and routine mammograms are good ways to manage overall breast health.
Outlook / Prognosis
Do breast cysts increase your risk of breast cancer?
Breast cysts don’t increase your breast cancer risk. But you should have any new lump checked out by your healthcare provider. Breast cysts usually disappear after menopause.
What questions should I ask my healthcare provider about breast cysts?
If you’ve been diagnosed with a breast cyst, consider asking your provider:
- What type of breast cyst is it (simple, complicated or complex)?
- Does it need to be aspirated or removed?
- Do I need more frequent mammograms?
- Should I continue on hormone replacement therapy?
A note from Cleveland Clinic
Breast cysts are common, especially among women in their forties. The good news is that these cysts are almost always harmless. Though cysts are common, always have your healthcare provider check out any new lumps or bumps you find.
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