Breast cysts are fluid-filled sacs inside the breast, which are usually not cancerous (benign). You can have one or many breast cysts and they can happen in one or both breasts. They're often described as round or oval lumps with distinct edges. A breast cyst usually feels like a grape or a water-filled balloon, but sometimes a breast cyst feels firm.
Breast cysts don't require treatment unless a cyst is large and painful or uncomfortable. In that case, draining the fluid from a breast cyst can ease symptoms.
Breast cysts are common in women before menopause, between ages 35 and 50. But they can be found in women of any age. They can also occur in postmenopausal women taking hormone therapy.
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 with distinct 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
- Increase in breast lump size and breast tenderness just before your period
- Decrease in breast lump size and resolution of other symptoms after your period
Having breast cysts doesn't increase your risk of breast cancer. But having cysts may make it more difficult to find new breast lumps or other changes that might need evaluation by your doctor. Be familiar with how your breasts normally feel so that you'll know when something changes.
When to see a doctor
Normal breast tissue often feels lumpy or nodular. But if you feel any new breast lumps that persist after a menstrual period, or if an existing breast lump grows or changes, see your doctor right away.
Each of your breasts contains lobes of glandular tissue, arranged like petals of a daisy. The lobes are divided into smaller lobules that produce milk during pregnancy and breast-feeding. The supporting tissue that gives the breast its shape is made up of fatty tissue and fibrous connective tissue. Breast cysts develop as a result of fluid accumulation inside the glands in the breasts.
Breast cysts may be defined by their size:
- Microcysts are too small to feel, but may be seen during imaging tests, such as mammography or ultrasound.
- Macrocysts are large enough to be felt and can grow to about 1 to 2 inches (2.5 to 5 centimeters) in diameter. Large breast cysts can put pressure on nearby breast tissue, causing breast pain or discomfort.
Experts don't know what causes breast cysts. They may develop as a result of hormonal changes from monthly menstruation. Some evidence suggests that excess estrogen in your body, which can stimulate the breast tissue, may contribute to breast cysts.
After discussing your symptoms and health history, your doctor will do a breast exam and may order a diagnostic mammogram or a breast ultrasound. Based on the findings of the clinical breast exam and imaging tests, you may need fine-needle aspiration or a breast biopsy.
Your doctor will physically examine the breast lump and check for any other breast abnormalities. Because your doctor can't tell from a clinical breast exam alone whether a breast lump is a cyst, you'll need another test. This is usually either an imaging test or fine-needle aspiration.
Breast ultrasound 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 breast ultrasound and perform fine-needle aspiration instead.
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 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 diagnostic mammogram and or ultrasound. 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, and a sample of cells may be collected to check for cancer (fine-needle aspiration biopsy).
No treatment is necessary for simple breast cysts — those that are fluid-filled and don't cause any symptoms — that are confirmed on breast ultrasound or after a fine-needle aspiration. If the lump persists or feels different over time, follow up with your doctor.
Fine-needle aspiration may diagnose and treat a breast cyst if your doctor removes all the fluid from the cyst at the time of diagnosis, your breast lump disappears and your symptoms resolve.
For some breast cysts, however, you may need to have fluid drained more than once. Recurrent or new cysts are common. If a breast cyst persists through two to three menstrual cycles and grows larger, see your doctor for further evaluation.
Using birth control pills (oral contraceptives) to regulate your menstrual cycles may help reduce the recurrence of breast cysts. But because of possible significant side effects, birth control pills or other hormone therapy, such as tamoxifen, is usually only recommended in women with severe symptoms. Discontinuing hormone therapy after menopause may also help prevent breast cysts.
Surgery to remove a breast cyst is necessary only in unusual circumstances. Surgery may be considered if an uncomfortable breast cyst recurs month after month or if a breast cyst contains blood-tinged fluid or shows other worrisome signs.
To minimize discomfort associated with breast cysts, you might try these measures:
- Wear a well-fitted, supportive bra. If your breast cysts are painful, supporting your breasts may help relieve some discomfort.
- Apply a compress. If cysts are painful, either a warm or cool compress can offer relief. Applying an ice pack can also relieve pain.
- Avoid caffeine. There's no evidence linking caffeine and breast cysts. However, some women find symptom relief after eliminating caffeine from their diets. Consider reducing or eliminating caffeine — in beverages, as well as in foods such as chocolate — to see if your symptoms improve.
- Consider trying over-the-counter pain medications if your doctor recommends them. Some types of breast pain may be eased by the use of acetaminophen (Tylenol, others) or nonsteroidal anti-inflammatory drugs, such as ibuprofen (Advil, Motrin IB, others) or naproxen (Aleve, Naprosyn, others).
Evening primrose oil is a fatty acid (linoleic acid) supplement that's available over-the-counter. Some small studies suggest that evening primrose oil may ease menstrual cycle breast pain, sometimes associated with breast cysts. But more research is needed as studies have been small and uncontrolled, and the evidence isn't conclusive. Although the exact mechanism isn't clear, some experts believe that women deficient in linoleic acid are more sensitive to hormonal fluctuations during the menstrual cycle, resulting in breast pain.
Let your doctor know if you're taking any vitamins, herbal remedies or other dietary supplements.
You'll likely see your primary care provider to evaluate new breast lumps or changes in your breasts. You may be referred to a breast-health specialist based on a clinical breast exam or findings on an imaging test.
What you can do
The first evaluation focuses on your medical history. You'll discuss your symptoms, their relation to your menstrual cycle and any other relevant information. To prepare for this discussion, make lists that include:
- All your symptoms, even if they seem unrelated to the reason you scheduled the appointment
- Key personal information, including major stresses or recent life changes
- All medications, vitamins, herbal remedies and supplements that you regularly take
- Questions to ask your doctor, from most important to least important to be sure you cover the points you're most concerned about
Basic questions to ask your doctor include:
- What's causing my symptoms?
- Does having cysts increase my risk of breast cancer?
- What kinds of tests will I need?
- What treatment is likely to work best?
- What are the alternatives to the primary approach that you're suggesting?
- Are there any restrictions I'll need to follow?
- Are there any printed materials that I can take home? What websites do you recommend?
Don't hesitate to ask questions anytime you don't understand something.
What to expect from your doctor
Be prepared to answer questions that your doctor may ask, such as:
- When did you first notice the breast cyst or lump?
- Have you noticed a change in the size of the breast cyst or lump?
- What symptoms have you experienced, and how long have you had them?
- Do your symptoms occur in one or both breasts?
- Have any symptoms changed over time?
- Do you have breast pain? If so, how severe is it?
- Do you have nipple discharge? If so, does it occur in one or both breasts?
- How does your menstrual cycle affect the breast cyst or lump?
- When was your last mammogram?
- Do you have a family history of breast cysts or lumps?
- Have you previously had a breast cyst or lump, a breast biopsy or breast cancer