Medically Reviewed By William C. Lloyd III, MD, FACS

What is a cyst?

Cysts are benign sacs that contain fluid, cells, air, or other materials and may form anywhere in the body. As a rule, cysts in the lungs are air-filled, whereas those that form in the skin, lymph system, genitourinary system, or other internal organs are usually fluid-filled. The fluid in cysts may be watery or may contain blood.

Cysts can develop in response to vessel blockages, infection, parasitic diseases, or abnormal tissues. Cysts can also be present in both benign (noncancerous) and malignant tumors. They can be very small, even microscopic, or large enough to move an organ from its normal location.

Cysts usually are not serious. Many will require no treatment and many resolve on their own. Treatment is required if cysts begin to interfere with organ functioning, if an infected cyst is left untreated, if there is suspicion of cancer, or if troubling symptoms develop.

Some cysts near the surface of the body can be drained in an outpatient setting. Others require surgical removal (excision) of the cyst or of tissues damaged by the cyst. Cysts that form within the brain can enlarge and cause neurologic problems.

There are a number of different types of cysts. Common locations for cysts are the skin, the ovaries, the joints and tendons, breast, pancreas, glands of the eyelids, and the kidneys. Cysts are sometimes named according to their anatomic location.

Seek prompt medical care if you have abdominal swelling with abdominal, pelvic, or lower back pain that may be severe; unexplained weight loss; frequent urination or incontinence; and a loss of appetite, or if you are being treated for a cyst but symptoms recur or are persistent.

What are the different types of cysts?

Common locations for cysts are the skin, ovaries, joints and tendons, breast, pancreas, glands of the eyelids, and the kidneys. Cysts are sometimes named according to their anatomic location.

Types of cysts include:

  • Baker’s cyst, a sac filled with joint fluid (synovial fluid) that forms behind the knee where it bends
  • Bartholin gland cyst, a mucus-filled sac that forms in a gland at the vaginal opening
  • Brain and spinal cord cysts, which may form very early in development or later in life. Examples include arachnoid cyst, pineal gland cyst, epidermoid cyst, dermoid cyst, and tumor-associated cyst.
  • Breast cyst, a fluid-filled lump in the breast that is nearly always benign (noncancerous). This contrasts with solid lumps, which may be malignant (cancerous) or benign, such as a fibroadenoma.
  • Chalazion, a cyst in the eyelid, is usually painless. Trapped oil and cell debris fill a chalazion, which then incites an inflammatory reaction directed against the cyst contents.
  • Ganglion cyst, a fluid-filled lump or mass that develops along a tendon or joint
  • Kidney cyst, a fluid-filled sac (solitary cyst) that can form on or within the kidney
  • Ovarian cyst, a fluid-filled sac on an ovary
  • Pilonidal cyst, a semisolid lump in the crease of the buttocks caused by misdirected fetal hair and glandular structures getting trapped underneath the skin
  • Skin cyst, including sebaceous cysts and epidermoid cysts. They look like smooth lumps just under the skin. A sebaceous cyst is a sebaceous gland filled with a fatty yellow substance (sebum). An epidermoid cyst is formed by skin cells that fill the cyst with keratin. It may drain a foul-smelling substance.

What are the signs and symptoms of cysts?

Many cysts exhibit no symptoms. A detectable symptom of cysts occurring either on the skin or in tissue near the surface of the body (for example, a breast cyst) is a lump on or beneath the skin that is red, tender, or produces swelling. The development of multiple cysts in the ovary (polycystic ovary syndrome) may lead to an imbalance in hormone production. This can result in menstrual problems and hair growth (hirsutism, masculinization).

Common symptoms of cysts

The symptoms of a cyst depend on the location and size of the cyst. Many cysts will not produce any symptoms. Cysts associated with infection or cancers may cause a number of different symptoms. In some cases, such as benign cysts of the skin, a localized lump or swelling is the only symptom. If infected, the lump may be red and painful to touch.

Symptoms of a cyst can include:

  • Abdominal distension, pain or cramping
  • Bulging or protrusion of the eye (orbital dermoid cyst)
  • Fever
  • Irregular or absent menses (polycystic ovary syndrome)
  • Lumps or nodules beneath the skin
  • Muscle pain, especially with breathing or with muscle use
  • Muscle weakness
  • Nausea; loss of appetite
  • Neurologic abnormalities (altered vision, abnormal gait, loss of coordination)
  • Redness or tenderness around a raised area on or below the surface of the skin

Serious symptoms that might indicate a life-threatening condition

In some cases, cysts can be life-threatening. Seek immediate medical care (call 911) for serious symptoms including:

What causes cysts?

Cysts can be present at birth or be acquired throughout life. Cysts can develop in response to blockages of the flow of body fluids, such as clogged sebaceous glands, as seen in cystic acne. They can also develop in response to infection or to a long-standing abscess or ingrown hair, as is the case with pilonidal cysts, which are cysts that occur along the crease between the buttocks. Cysts often form around a foreign object, such as a splinter in the skin.

Cysts in other organs may form as a response to inflammation and normal wear and tear. Cysts are also present in some benign tumors and cancers. Benign cysts are common in the ovary and breast; less commonly, cysts can be found in cancers of these organs. Cysts in the muscles, liver, brain, lungs and eyes may be caused by parasitic diseases.

What are the risk factors for cysts?

Cyst risk factors vary based on the type of cyst and the underlying condition that causes the cyst. It is not possible to predict the development of all types of cysts or to prevent their occurrence. However, you can help prevent infection of certain cysts by seeking medical care when you experience symptoms associated with a cyst.

How do doctors diagnose cysts?

For cysts that develop near the surface of the skin, healthcare providers can usually diagnose by the appearance of the cyst and by feeling (palpating) it. Dermatologists and some family medicine doctors can diagnose and treat skin cysts.

Specialists who diagnose and treat specific types of cysts include gynecologists, nephrologists, neurosurgeons, orthopedic surgeons, and general surgeons.

Tests and procedures that can help diagnose cysts include:

  • Biopsy, such as needle biopsy, to confirm that the cyst is noncancerous (benign)
  • Blood tests, to help pinpoint any underlying cause of cysts
  • CT (computed tomography) scan or MRI (magnetic resonance imaging), to determine the size, makeup and location of the cyst, and help plan surgical removal if necessary
  • Ultrasound, to determine the size and location and whether the cyst is solid or filled with fluid

How are cysts treated?

Many cysts go away on their own. Other cysts must be surgically removed, or the underlying disorder, such as polycystic ovary syndrome, may require medical treatment, such as medication. Drainage of cyst contents, without removing the wall or structure of the cyst, may lead to recurrence. Depending on the cause of your cysts, it is important to follow your treatment plan to ensure that you are completely rid of both the cysts and any primary disorder that may have caused them.

Medical treatments for cysts

Treatment of infectious causes of cysts may include surgical drainage of the infection, antibiotics, or anthelmintic medications (for treating parasitic worm infections). Pain-reliever medications may be used for cysts associated with discomfort. Cysts associated with tumors or cysts that interfere with organ function may require surgical removal. Depending on the type, size and location of the cyst, removal may involve an in-office procedure with local anesthetic, a minor surgical procedure with regional anesthetic, or major surgery under general anesthesia.

Home remedies for cysts

Cysts involving the skin or glands near the surface of the skin may go away faster by applying a warm and clean compress several times a day. Never try to pierce or drain the cyst. If there are any signs of infection, see your healthcare provider promptly.

What are the potential complications of cysts?

Complications of untreated or poorly controlled cysts can be serious, even life-threatening in some cases. You can help minimize your risk of serious complications by following the treatment plan you and your healthcare professional design specifically for you.

Complications of cysts depend widely on the location and can include:

  • Cyst rupture with release of cyst contents (resulting in inflammation)

  • Encephalitis (inflammation and swelling of the brain due to a viral infection or other causes)

  • Organ failure

  • Spread of cancer

  • Spread of infection
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  2. Kahan S, Miller R, Smith EG (Eds.). In A Page Signs & Symptoms, 2d ed. Philadelphia: Lippincott, Williams & Williams, 2009.
  3. Epidermoid Cysts. Mayo Clinic. 
  4. Cysts (Overview). Harvard Health Publishing.
  5. Chalazion. Cleveland Clinic. 
  6. Bartholin gland cysts. Merck Manual. 
  7. Brain and spinal tumours. Canadian Cancer Society. 
  8. Bhatt AS, Mhatre R, Nadeesh BN, Mahadevan A, Yasha TC, Santosh V. Nonneoplastic Cystic Lesions of the Central Nervous System-Histomorphological Spectrum: A Study of 538 Cases. J Neurosci Rural Pract. 2019;10(3):494-501. doi:10.1055/s-0039-1698033. Retrieved from  
  9. Sebaceous Cysts. Cleveland Clinic. 

Medical Reviewer: William C. Lloyd III, MD, FACS
Last Review Date: 2021 Aug 17
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