Breast cyst

Medical quality assurance by Dr. Albrecht Nonnenmacher, MD at May 22, 2016
StartDiseasesBreast cyst

Most women have non-cancerous breast conditions which include breast cysts. Breast cysts are most common among women in their 40s but can affect women of any age. These cysts are non-cancerous and do not increase the risk of developing breast cancer.


Definition & Facts

Breast cysts are benign fluid-filled sacs that form in the tissue of the breast. They are non-proliferative, meaning that their presence does not increase a person’s likelihood of developing cancer. It is also common for women with dense fibrocystic breast tissue to have breast cysts. Fibrocystic tissue can make it difficult to read mammograms and can complicate a doctor’s ability to diagnose a benign cyst without further testing.

The liquid inside of the cyst is not milk unless the cyst is a galactocele; it is similar to the fluid that collects inside of a blister. If pus collects in the breast due to bacterial infection, it is classified as an abscess or breast infection (mastitis).

Symptoms & Complaints

Breast lumps can vary in size, and may be present in one or both breasts. Many breast cysts, a type of breast lump, are so small that they are asymptomatic and undetectable with breast self-examinations.

Macrocysts, large cysts that can be between 2.5 and 5 cm in diameter, manifest as oval-shaped lumps in the breasts. Due to their size and sudden onset, the detection of macrocysts can be frightening for a patient even though the condition is often harmless.

Cysts may feel like they are filled with fluid, but it is not always easy to determine the contents without further testing. For those with larger cysts, the most common symptom is breast pain. As the sac fills with fluid, it puts pressure on surrounding breast tissue. Some people experience white discharge from the nipple of the affected breast.


The breast is made up of several types of tissue. Breast lobules produce milk, and ducts carry milk out through the nipples. The area surrounding the lobules and ducts is made up of fatty tissue and fibrous connective tissue. Usually, breast cysts develop in the fatty tissue near places where lobules and ducts join.

Hormonal shifts are believed to be the primary cause. Fluctuations in estrogen seem to correspond with the development of breast cysts. Women will often experience swelling and tenderness of the cysts prior to their menstrual cycle. Once the cycle is complete, the soreness and swelling abates. This is referred to as cyclical breast pain.

Women on hormone therapy for menopause may also be at a higher risk for experiencing breast cysts. Galactoceles, which result from blocked milk ducts, typically develop when a woman ceases breastfeeding. Injuries can also encourage the formation of cysts.

Diagnosis & Tests

Monthly self-examinations can help to determine variation in breast tissue. A breast cyst may appear suddenly and may change in connection with the menstrual cycle. In cases where benign breast cysts with little pain develop, physicians may recommend self-monitoring. It is not always possible to tell the contents of a breast cyst through manual screening.

Health care professionals may recommend an ultrasound to determine the shape, size, and contents of the lump. A fluid-filled cyst with a regular oval shape and thin walls doesn’t cause much concern. Breast cysts with thicker walls, solid particles mixed with fluid, or a solid mass will require further testing.

The doctor may perform a needle biopsy to screen for cancer in cases where he or she discovers abnormalities. In large or abnormal cysts, clinical screenings every 6-12 months may be recommended. This could include mammograms or ultrasounds of the affected areas.

Usual hyperplasia and atypical hyperplasia may also be detected in the diagnostic phase. These conditions manifest as lumps, and they are also benign. Unlike breast cysts, usual and atypical hyperplasia are proliferative, meaning that they do increase a person’s chance of getting breast cancer.

Treatment & Therapy

As long as the pain is not disruptive and there is nothing unusual about the cyst, patients may allow them to recede on their own. Since breast cysts are often caused by hormonal fluctuations, they may resolve when hormonal levels change. Over-the-counter pain relievers such as ibuprofen, acetaminophen, or naproxen can help to relieve minor pain. Warm or cool compresses can also ease tenderness. A supportive bra can take the pressure off tissues surrounding the cyst, which can reduce discomfort.

In cases where the cyst has become large or bothersome, fine-needle aspiration may be recommended. In this treatment, the doctor administers a local anesthetic. Then, fluid is drawn out of the cyst via a thin needle. This should relieve the pressure on the surrounding tissues and thus the discomfort. Sometimes the cyst will fill with fluid again after a fine-needle aspiration. In this case, surgical intervention may be an option.

Prevention & Prophylaxis

While it is not possible to eliminate the potential for breast cysts, some steps can be taken to reduce their occurrence and severity. Conclusive research is still to be conducted about this condition, but there are a few practices that seem to correlate with reducing symptoms. Cutting caffeine by reducing the intake of coffee, sodas, and chocolate is one means of decreasing the likelihood of developing cysts.

Reducing salt intake is another means of prevention since fluid retention encourages irritation and formation of cysts. In some cases, women are prescribed diuretics to prevent them from retaining excess fluid. Evening primrose oil is a plant derivative that may reduce inflammation and prevent breast cysts.

For severe cases, oral contraceptives may be prescribed to curb the estrogen fluctuations responsible for the condition. Since usual and atypical hyperplasia increase the risk of cancer, the cancer-preventing drug, tamoxifen, may be prescribed when these conditions are detected. However, tamoxifen has side effects such as increasing the risk of endometrial cancer.