Fluid-Filled Sacs In Breast – Symptoms Causes And Diagnosis Of Breast Cysts

Fluid-Filled Sacs In Breast – Symptoms Causes And Diagnosis Of Breast Cysts

Breast changes are very common; right from it begins to form in a young girl to start of the menstruation, during the pregnancy phase and after menopause, it goes on changing. Finding lumps or cysts in the breast could take you to the stress route and inculcate the feeling of having a cancer. If this is the case, then let’s find out what’s all about breast cysts.

Breast Cysts

Breast cysts are referred to fluid-filled sacs that develop inside the breast. These cysts are usually non-cancerous or benign in nature. A woman can have one or multiple breast cysts and they can occur in one or both the breasts. These fluid-filled sacs are also called as round or oval lumps having distinct edges.

Usually, these cysts feel like water-filled balloon, but at times they feel firm. Breast cysts or lumps generally don’t require any treatment unless large in size, painful or feel uncomfortable. They can be commonly found in women between the age group of 35 and 50. Cysts can also appear in postmenopausal women who are taking hormone therapy.

Symptoms of breast cyst

Breast cysts can occur in one or both the breasts. One should keep an eye for following signs and symptoms:

  • Lump which is smooth, movable and round or oval in shape
  • Pain and tenderness in the area of breast lump
  • Yellow or dark brown discharge from nipples
  • Increase in breast lump size and tenderness before menstrual periods
  • Decrease in size of breast lump accompanied by other symptoms after menstrual period

Even if a woman has breast lump, it does not mean she is at increased risk of breast cancer. However, having cysts in the breast can make it difficult for the doctor to find new breast lumps or other changes occurring inside. So, one should be cautious of any changes in the breast.

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What causes breast cysts?

Each breast of a woman contains lobes of glandular tissue and these lobes are subdivided into smaller lobules which produces milk during pregnancy and in breastfeeding phase. Breasts are surrounded by fibrous and fatty tissue and sometimes fluid accumulates in these tissues and form lumps. It is also believed that breast cyst develops naturally as you age.

Breast cysts can be defined by their size. These are basically divided into two forms:


These cysts are tiny and one cannot feel them. But they can appear on imaging tests such as ultrasound or mammogram.


These cysts can be felt and the size can be as much as 2.5 to 5 cm (1-2 inches) in diameter. These macrocysts can put pressure on nearby tissue and can cause pain or discomfort.

What exactly causes breast cysts is unknown, as of yet. Some experts believe they form as a result of changes in hormone levels during menstruation. And some evidence does suggest that excess of estrogen hormone in the body can excite breast tissue and might contribute in the development of cysts.

Diagnosis of breast cysts

After discussing the symptoms and medical history, the doctor will first physically examine the breast and check for any abnormalities. Since it’s difficult for a doctor to tell from a physical breast examination that the lump is a cyst or not, you will require other tests.

Breast Ultrasound 

This imaging technique can help doctor determine character and shape of the lump. If lump looks like a fluid-filled sac, it indicates a cyst. On the other hand, if it is a solid mass, it would be most likely a noncancerous lump such as fibroadenoma. However, solid lumps could also indicate breast cancer.

Fine-needle aspiration 

The doctor may skip ultrasound and recommend a biopsy if he or she could feel the lump in breast or if the lump is some kind of solid mass. Fine-needle aspiration is a biopsy procedure during which the doctor inserts a thin needle into the breast lump and tries to extract some fluid. Often, this biopsy is guided by ultrasound for accuracy.

  • If the fluid comes out and lump goes away, it can be confirmed that it’s a breast cyst.
  • If the fluid in the lump is not bloody and the lump disappears after extracting fluid, you would require no further testing or treatment.
  • If the fluid is bloody and lump does not disappear, the sample might be send for lab testing and you might be referred to a breast surgeon for follow up.
  • If no fluid comes out of the lump, the doctor would be performing either mammogram or ultrasound to further evaluation. Lack of fluid or the lump that doesn’t goes away after aspiration, suggests that the lump is solid and need sample biopsy for evaluation of cancer.

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How Breast Cysts Are Treated?

Basically, simple breast cysts that are fluid filled and are not causing any trouble will need no treatment. However, if the lump persists or seems to be growing over the time, you must consult a doctor. Generally, following treatments are performed depending on the case.

Fine-needle aspiration

This technique can perform both diagnosis and removal of cyst if they are just fluid filled sacs and your symptoms resolves after the removal. However, you may need fluid drainage more than once as cysts can recur.

Medication and Hormone therapy

Birth control pills used to regulate menstrual cycles can also be helpful in preventing the recurrence of cysts. But since these medications can induce possible side effects, pills such as tamoxifen are only recommended to women with serious symptoms. Women who discontinue hormonal therapy after menopause may also have less chances of recurrence.


Surgical procedures are uncommon and are used only in situations where breast cysts recurs month after month or it is bloody or shows some other severe signs.

Breast cysts are often lumpy and doesn’t cause any harm. However, any lump that persists after a menstrual period or changes month on month, it’s time to consult the doctor right away.


1. Fibrosis and Simple Cysts in the Breast(2017, September 20). American cancer society read more 
2. Benign Breast Conditions(2017, June 05). Familydoctor read more
3. Benign Breast Problems and Conditions(2017, March). ACOG read more
4. Breast lump(2017, November 26). MedlinePlus read more
5. Breast Cyst(n.d.). National Breast Cancer Foundation 
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