Milena Stojanovic MD

Primarius  Milos Pocekovac MD, PhD

Sava Stajic MD,MSc

What is a breast cyst?

They are one of the most common benign diseases of the breast. It has been estimated that 7-10% of all women will develop a cyst during their reproductive life. Some studies showed that in 27% of cases from 300 women that had mastectomies had also breast cysts. According to Hagens a large cyst is a palpable cyst.

Macro cysts

Or palpable cysts are around 20% -25% of cases and the size is around 2,5-5cm in diameter.

Micro cysts

Or not palpable, are usually found during mammography, ultrasound or even at the microscopic examination

Cysts can contain various chemical substances from pigmented apocrine secretions to lipofuscin, lipo proteins and hemoglobin.

Cysts usually appear between the ages of 35 to 50 years old and they can disappear during menopause in case of taking hormone substitution therapy. Studies showed that 78% of women have cysts during the age 35-50. Years old, and that only 2,3% in women under. Rarely they can appear in elderly women and they do not show tendency to grow. They can be connected to a papillary tumor when the fluid in the cyst is hemorrhagic in content.


Most cysts can contain 5 to 10 ml of fluid, some can contain over 75 ml.

Cysts are a common finding in the breast. This is an epithelized area contacting 2 layers: inner (lumen) epithelial surface and outer myoepithelial cell layer. Usually they are multi focal and bilateral but to a great extent they differentiate in the number and size.

Why does it form?

Exact mechanism is no clear, but it is assumed that the surplus of estrogen over progesterone has a role in cyst formation. During the menstrual cycle stroma and epithelium of the breast are going through a repeated process of involution, and the cyst appears as an undesired product of this process. Cysts come from the terminal canals of lobular units. If the stroma that surrounds a unit involutes too dark, acinus epithelium stays and can form micro cysts. There is a predilection to macro cysts.

How to recognize it?

Cysts are smooth in surface round and oval shape, movable. Upon palpation there is a feeling of palpating soft grapes or a water balloon

It can be one or more cysts in one breast. As in fibro adenomas 55% of cysts are in the left breast and 45% in the right. Two thirds of them appear in the upper lateral quadrant and afterwards in the upper medial quadrant. Cysts are rare in the lower half of the breast.

Are cysts painful?

Usually they are asymptomatic and discovered by the patent by accident. However, there are ones that produce pain and some symptoms. Pain is generated by distension of the surrounding tissue or leakage of the fluid from the cyst that causes a chemical reaction. Pain is usually not associated with the menstrual cycle and it is not connected to the size of the cyst. However, large and tense cysts that are harder in consistency can be an indicative sing of a lesion of another origin. In some women, premenstrual enlargement is followed by pain, and after the cycle the cysts become smaller and pain disappears. Rarely the cysts make a communication with the nipple and start draining in this way.

 If there is an ultrasound confirmation of a cyst puncture with aspiration should be performed.

How to treat cysts?

If there is a palpable cyst with pain perform the aspiration.

What is aspiration?

With a help of a large wide needle and syringe 10 to 20 ml we aspirate the content of the cyst.

Is anesthesia required?

No, the procedure is almost painless.

Can cysts come back after aspiration?

Yes, they can come back. It is reasonable to do another aspiration if the content is not hemorrhagic. However, if the cyst keeps reappearing an excision should be performed to remove the entire cyst.

Is cytology performed on the aspirate?

Cytological examination is performed only if the content is hemorrhagic.

What is a complex cyst?

Complex (complicated or atypical) cyst is a cyst that is described as an echogenic or solid cyst upon ultrasound. They make around 5% – 5,5% of all ultrasound verified cysts. Comparing to a simple cyst they have a solid component or debris in its content. Radiological follow up is advised, with aspiration or even a core biopsy or an excision biopsy.

Are cysts connected to breast cancer?

Many years ago Hagens had confirmed that macroscopic cysts are connected to certain types of breast cancer but the risk is very low.

Bundred et al showed times increased risk in women that had cyst aspiration. Risk is even bigger in women with multiple or bilateral cysts.  In a series of 352 women with cysts, 14 developed breast cancer during the 7 years they were followed.  

It can be said that cysts are an indicator of increased risk, but a cyst on its own is not a pre malignant state.

Dixon et al published a study that showed the total risk, regardless of the type of the cyst. Main relevant factor that influenced the risk of breast cancer in the study was age and the greatest risk was in women that had developed cysts before the age of. It is considered reasonable to enter a screening program by the age of 40.  

Malignancy rate in complex cysts is 0,3%.

Hormone therapy

The us of contraceptive pills to regulate menstrual cycle can lower the incidence of cysts. But due to serious adverse effects, contraceptive pills and other hormonal therapy, such as tamoksiphen, is usually just recommended for women with severe symptoms.  Dixon et al proved that after giving tritium hormone (dihydroepiandrosterone sulfate) an apocrine fluid is appearing in the cyst within 2hr, and remains there for the next 3 years. Danasole, spironolactone and yellow night flower can prevent this process, which opens up therapy possibilities.  Studies have shown a significant (75%) in the number of cysts after danasole, 100mg 3 times a day in 3 months. The benefit was even better after 6 months, or 3 months after the discontinuation of therapy. This shows that this treatment would benefit the more difficult cases with pain.

Surgical excision is indicated if the cysts after an aspiration refill or if the content presents as hemorrhagic.

Alternative methods in treatment of painful cysts:

      1. Avoid caffeine
      2. Avoid salts in diet and specially before the menstrual cycle begins.
      3. Take yellow night flower oil.
      4. Wear comfortable undergarments.
      5. Cold and warm compresses
      6. NSAID (eg. ibuprophene)

Caffeine, salt, yellow night flower oil has effect on the pain in the breast but there is no reliable data that they are related to the cysts. However, some patients report relief of symptoms.