Breast Cyst

If you have a high risk of breast cancer, you may require frequent monitoring or additional testing. There aren’t any other life-threatening complications of breast cysts. They can sometimes become infected, or can become large, tense and painful and require aspiration.

There are three types of breast cysts:

• Simple breast cyst: Filled entirely with fluid, simple cysts are always noncancerous. There’s no solid area in the cyst and the cyst wall is smooth. They make up about 90% of all breast cysts.
• Complex breast cyst: This type of cyst, which has a mix of fluid and solid components, may be breast cancer in up to 20% of cases. Your provider typically biopsies the tissue, which means they remove part of your breast tissue and send it to a lab for analysis.
• Complicated breast cyst: A complicated cyst is fluid-filled, but may have some cloudiness to the fluid, or the borders may be somewhat irregular. Sometimes, these are aspirated with a needle biopsy and then the tissue is sent for analysis. Other times, a provider may recommend a follow-up appointment in six months because there’s just a small chance (less than 2%) of it being cancerous.

Breast cysts can also be microcysts or macrocysts. Most breast tissue contains microcysts, which are very tiny and may be seen by ultrasound or even just under a microscope. Macrocysts are larger and can often be felt.

Breast cysts may be found in one or both breasts. Signs and symptoms of a breast cyst include:

• A smooth, easily movable round or oval lump that may have smooth edges — which typically, though not always, indicates it’s benign
• Nipple discharge that may be clear, yellow, straw colored or dark brown
• Breast pain or tenderness in the area of the breast lump
• An increase in breast lump size and breast tenderness just before your period
• A decrease in breast lump size and resolution of other symptoms after your period

Needed tests may include:

• Mammography. Large cysts and clusters of small cysts can usually be seen with mammography. But microcysts can be difficult or impossible to see on a mammogram.
• Breast ultrasound. This test can help your doctor determine whether a breast lump is fluid filled or solid. A fluid-filled area usually indicates a breast cyst. A solid-appearing mass most likely is a noncancerous lump, such as a fibroadenoma, but solid lumps also could be breast cancer.

Your doctor may recommend a biopsy to further evaluate a mass that appears solid. If your doctor can easily feel a breast lump, he or she may skip imaging tests and perform fine-needle aspiration to drain the fluid and collapse the cyst.

During a fine-needle aspiration, your doctor inserts a thin needle into the breast lump and attempts to withdraw (aspirate) fluid. Often, fine-needle aspiration is done using ultrasound to guide accurate placement of the needle. If fluid comes out and the breast lump goes away, your doctor can make a breast cyst diagnosis immediately.

• If the fluid is not bloody and has a straw-colored appearance and the breast lump disappears, you need no further testing or treatment.
• If the fluid appears bloody or the breast lump doesn’t disappear, your doctor may send a sample of the fluid for lab testing and refer you to a breast surgeon or to a radiologist — a doctor trained to perform imaging exams and procedures — for follow-up.
• If no fluid is withdrawn, your doctor will likely recommend an imaging test, such as a diagnostic mammogram or ultrasound. The lack of fluid or a breast lump that doesn’t disappear after aspiration suggests that the breast lump — or at least a portion of it — is solid. A sample of the tissue may be collected to check for cancer.