A cyst is a sac-like pocket of membranous tissue that contains fluid, air, or other substances. Cysts can grow almost anywhere in your body or under your skin.

There are many different types of cysts. Most cysts are benign, or noncancerous.

Whether a cyst needs treatment depends on a number of factors, including:

  • the type of cyst
  • the location of the cyst
  • if the cyst is causing pain or discomfort
  • whether the cyst is infected

If you’re not sure of what your own skin condition is, you can take a picture and send it to an online dermatologist.

Cysts can vary in appearance depending on their type and location. Here are 13 different types of cyst.

Warning: Graphic images ahead.

Epidermoid cyst

Image by: Steven Fruitsmaak (Own work) [CC BY-SA 3.0 (creativecommons.org/licenses/by-sa/3.0)], via Wikimedia Commons

  • Epidermoid cysts are small, slow-growing, benign cysts most commonly found on the face, head, neck, back, or genitals.
  • They're usually caused by a buildup of keratin under the skin.
  • They look like skin-colored, tan, or yellowish bumps filled with thick material.
  • They may become swollen, red, and painful if they are infected.
Read full article on epidermoid cysts.

Sebaceous cyst

Image by: Tnek46 at English Wikipedia (Transferred from en.wikipedia to Commons.) [Public domain], via Wikimedia Commons

  • Sebaceous cysts are found on the face, neck, or torso
  • Large cysts may cause pressure and pain
  • They are noncancerous and very slow growing
Read full article on sebaceous cysts.

Breast cyst

Image by: Nevit Dilmen [CC BY-SA 3.0 (creativecommons.org/licenses/by-sa/3.0) or GFDL (gnu.org/copyleft/fdl.html)], via Wikimedia Commons

  • Most breast lumps are noncancerous, but there are many possible causes for a lump in your breast.
  • It's important to be familiar with how your breasts normally feel so you are aware of changes.
  • Instead of performing breast self-examination, most experts recommend that women simply be aware of what their breasts normally look and feel like and report any changes to their healthcare provider.
  • You should make an appointment to see a healthcare provider if you discover a new lump; an area of your breast is noticeably different than the rest; a lump changes or grows larger; you notice bloody discharge from the nipple; or you have an inverted nipple (if it was not always inverted).
Read full article on breast cysts.

Ganglion

Image attribution: GNU Free Documentation License/Wikimedia

  • A ganglion cyst is a round, fluid-filled lump of tissue that usually appears along tendons or joints, especially in the hands, wrists, ankles, and feet.
  • Fluid accumulation can occur due to injury, trauma, or overuse, but often the cause is unknown.
  • Ganglion cysts are common, harmless, and don't cause pain or problems unless they grow and put pressure on other structures.
Read full article on ganglion cysts.

Pilonidal cyst

Image by: JerryTahl (Own work) [Public domain], via Wikimedia Commons

  • A pilonidal cyst is a common skin condition that forms in the cleft at the top of the buttocks.
  • It’s believed to be caused by a combination of changing hormones (because it occurs after puberty), hair growth, and friction from clothes or from spending a long time sitting.
  • It consists of a small hole or tunnel in the skin that may become infected and fill with fluid or pus.
  • Signs of an infection include pain when sitting or standing, red or sore skin around the area, pus or blood draining from the abscess, causing a foul odor, swelling of the cyst, and hair protruding from the lesion.
Read full article on pilonidal cysts.

Ovarian cyst

Image by: Euthman [Public domain], via Wikimedia Commons

  • Ovarian cysts are fluid-filled sacs that develop on one or both of the ovaries.
  • They may develop as a normal part of the female reproductive cycle or be pathologic.
  • They may be asymptomatic or painful.
  • Symptoms include abdominal bloating or swelling, painful bowel movements, pelvic pain before or during the menstrual cycle, painful intercourse, pain in the lower back or thighs, breast tenderness, nausea, and vomiting.
  • Severe symptoms such as sudden, sharp pelvic pain, fever, faintness, or dizziness are signs of cyst rupture or ovarian torsion.
Read full article on ovarian cysts.

Chalazia

Image by: Jordan M. Graff, MD/Wikimedia

  • Chalazia is a small, usually painless lump or swelling on your upper or lower eyelid.
  • It's caused by a blocked meibomian or oil gland.
  • It may be red, swollen, and painful if an infection is present.
Read full article on chalazia.

Baker’s (popliteal) cyst

Image by: Hellerhoff [GFDL (gnu.org/copyleft/fdl.html) or CC BY-SA 3.0 (creativecommons.org/licenses/by-sa/3.0)], from Wikimedia Commons

  • This fluid-filled swelling causes a lump at the back of the knee, leading to tightness, pain, and restricted movement.
  • This condition is due to a problem that affects the knee joint, such as arthritis, inflammation from repetitive stress, or a cartilage injury.
  • Symptoms include mild to severe pain, stiffness, limited range of motion, swelling behind the knee, bruising on the knee and calf, and rupturing of the cyst.
  • A popliteal cyst often doesn't need treatment and will go away on its own.
Read full article on Baker’s (popliteal) cysts.

Cystic acne

  • This is the most severe type of acne, and it develops when cysts form deep underneath your skin.
  • It can result from a combination of hormone changes, bacteria, oil, and dry skin cells that get trapped in your pores.
  • Acne cysts may occur on the face, chest, neck, back, and arms. Large, red, painful, pus-filled cysts and nodules may form, rupture, and leave scars.
Read full article on cystic acne.

Ingrown hair cyst

  • These cysts start off as a hair that grows down or sideways instead of out, becoming ingrown.
  • They’re common among people who shave, wax, or use other methods to remove their hair.
  • Ingrown hair cysts may become infected.
  • They appear as pimple-like bumps under the skin that may be red, white, or yellow in color, with or without a central, visible hair.
  • Cysts may become red, warm, and tender to the touch if they are infected.
Read full article on ingrown hair cysts.

Pilar cyst

Image by: DermNet New Zealand

  • Pilar cysts are noncancerous, flesh-colored, round bumps that develop under the surface of the skin.
  • This type of cyst is caused by protein buildup in a hair follicle.
  • They’re commonly located on the scalp.
  • They’re also painless, firm, smooth, and slow-growing.
Read full article on pilar cysts.

Mucous cyst

Image: Wikimedia

  • A mucous cyst is a fluid-filled swelling that occurs on the lip or the mouth.
  • They develop when the mouth’s salivary glands become plugged with mucus.
  • They’re commonly caused by trauma to the oral cavity, such as lip biting, piercings, and salivary gland disruption.
  • Mucous cysts are small, soft, pinkish or bluish nodules.
Read full article on mucous cysts.

Branchial cleft cyst

Branchial cleft cyst

Image by: BigBill58 (Own work) [CC BY-SA 4.0 (https://creativecommons.org/licenses/by-sa/4.0)], via Wikimedia Commons

  • Branchial cleft cyst is a type of birth defect in which a lump develops on one or both sides of a child’s neck or below the collarbone.
  • It occurs during embryonic development when tissues in the neck and collarbone, or branchial cleft, don’t develop normally.
  • In most cases, a branchial cleft cyst isn’t dangerous, but it may cause skin irritation or infection and, in rare cases, cancer.
  • Signs include a dimple, lump, or skin tag on your child’s neck, upper shoulder, or slightly below their collarbone.
  • Other signs include fluid draining from your child’s neck, and swelling or tenderness that usually occurs with an upper respiratory infection.
Read full article on branchial cleft cysts.

A cyst can appear as a bump on your skin. It may also feel like a small lump if it’s growing just under your skin.

Some cysts grow deep inside your body where you can’t feel them. However, they may cause or be related to other symptoms. For example, ovarian cysts, such as those that result from polycystic ovary syndrome (PCOS), may cause problems with ovarian and reproductive function. Polycystic kidney disease (PKD), which causes cysts to form in the kidney, can adversely affect kidney function.

Cysts usually grow slowly and have a smooth surface. They can be tiny or very large. Most cysts aren’t painful. They usually don’t cause problems unless they’re:

  • infected
  • very large
  • impinging on a nerve or blood vessel
  • growing in a sensitive area
  • affecting the function of an organ

Cysts form for different reasons. They can be caused by:

  • infections
  • inherited diseases
  • chronic inflammation
  • blockages in ducts

The exact cause depends on the type of cyst.

There are hundreds of different types of cysts. They can grow almost anywhere in your body. Some cysts occur as part of another condition, such as PCOS or PKD. Some of the more common types of cysts include the following:

Epidermoid cyst

These are small, benign bumps filled with keratin protein. If you have trauma around a hair follicle within the skin, an epidermoid cyst may occur. If part of the top layer of your skin, called the epidermis, grows deeper instead of moving outward toward the surface to eventually be shed off, an epidermoid cyst will have a chance to form.

In rare cases, epidermoid cysts can be caused by an inherited condition called Gardner’s syndrome.

Sebaceous cyst

Sebaceous cysts often form within sebaceous glands. These glands are part of the skin and hair follicles. Ruptured or blocked sebaceous glands can lead to sebaceous cysts. Sebaceous glands make oil for your skin and hair. Sebaceous cysts fill with sebum and are less common than epidermoid cysts.

Ganglion cyst

These benign cysts usually form near the joint areas of your wrist or hand. However, they can also develop in your feet or ankle areas. The reason they form isn’t known.

Ganglion cysts tend to occur along a tendon sheath near a joint. They’re more common in women than in men.

Ovarian cyst

Ovarian cysts often form when the follicle that normally releases an egg doesn’t open. This causes fluid to build up and form a cyst.

Another common type of ovarian cyst occurs after the follicle releases the egg and improperly recloses and collects fluid. Ovarian cysts occur most often in women of menstrual age. They’re usually found during pelvic exams.

Ovarian cysts are associated with an increased risk of cancer when they occur after menopause.

Breast cyst

Benign cysts can develop in your breasts when fluid collects near your breast glands. They commonly occur in women in their 30s and 40s. They can cause pain or tenderness in the affected area.

Chalazia

Chalazia are benign cysts that occur on your eyelids when the oil gland duct is blocked. These cysts can cause tenderness, blurred vision, and painful swelling. If they get too big, they can cause vision problems.

Pilonidal cyst

These cysts form near the top, middle part of the buttocks. They’re usually filled with skin debris, body oils, hair, and other matter.

Pilonidal cysts occur more often in men than in women. They can develop when loose hairs become embedded in your skin. According to the Mayo Clinic, chronic infections in these cysts might increase your risk of a type of skin cancer called squamous cell carcinoma. Know the signs for different types of skin cancer to treat it early.

Baker’s cyst

A Baker’s cyst, also known as a popliteal cyst, is a fluid-filled cyst that forms at the back of the knee. These cysts are usually due to problems with the knee, like knee injury or arthritis. Mobility can be limited and painful with a Baker’s cyst.

Physical therapy, fluid draining, and medication can all be used to help treat a Baker’s cyst.

Cystic acne

Cystic acne results from a combination of bacteria, oil, and dead skin clogging the pores. It’s the most severe type of acne in young adults, but usually improves with age. Cystic acne can look like large, pus-filled boils on the skin. It can also be painful to the touch.

If you believe you may have cystic acne, your dermatologist can prescribe medications to help treat it.

Ingrown hair cyst

An ingrown hair cyst forms when a hair grows into the skin and a cyst forms beneath it. These cysts are more common in people who shave or wax to remove hair.

Most of the time, professional medical care isn’t needed to treat ingrown hair cysts. However, see a healthcare professional if you suspect it’s infected.

Pilar cyst

Pilar cysts are flesh-colored, benign lumps that form on the surface of the skin. Since they’re benign, they’re typically not cancerous. However, they can grow to a size that can be uncomfortable.

Removal is typically not necessary, but they can be removed for cosmetic preference.

Mucous cyst

A mucous cyst is a fluid-filled lump that forms on the lip or around the mouth when the salivary glands become plugged with mucous. The most common causes of mucous cysts include:

  • lip or cheek biting
  • lip piercings
  • rupture of the salivary gland
  • poor dental hygiene

Often, mucous cysts will go away on their own. However, if you have recurring or frequent mucous cysts, medical treatment may be required.

Branchial cleft cyst

Branchial cleft cysts are a type of birth defect that forms a lump on an infant’s neck or below the collarbone. This cyst can look like a large skin tag.

Healthcare providers usually recommend surgical removal to prevent future infection.

Schedule an appointment with your healthcare provider if your cyst becomes very painful or red. This could be a sign of a rupture or an infection.

A healthcare provider should check your cyst even if it isn’t causing any pain or other problems. Abnormal growths can be a sign of cancer. Your healthcare provider may want to remove a tissue sample for testing.

Home care

In some cases, cysts go away on their own. Putting a warm compress on a cyst can speed up the healing process by helping it drain.

You should never try to squeeze or pop a cyst on your own. This can lead to infection.

Medical care

Common methods of medical treatment for cysts include the following:

  • Your healthcare provider can drain fluids and other matter from the cyst using a needle.
  • Your healthcare provider can give you medications, such as a corticosteroid injection, to reduce inflammation in the cyst.
  • Your healthcare provider can surgically remove the cyst. This may be done if draining doesn’t work or if you have an internal cyst that’s hard to reach and requires treatment.

Benign cysts usually don’t cause long-term problems. Sometimes they even go away on their own.

Cysts can refill after being drained. If you have a cyst that continues to refill, you may want to consider having it surgically removed.

Your healthcare provider will discuss treatment if you have cancerous cysts. The outlook will vary depending on the type of cancer involved.

Most types of cysts can’t be prevented. However, there are exceptions.

Women prone to ovarian cysts may be able to prevent new cysts from forming by using hormonal contraceptives.

Cleaning your eyelid near the eyelash line with a gentle cleanser can help keep the oil ducts from becoming blocked. This may help prevent chalazia.

You can prevent pilonidal cysts from forming by keeping the skin in the affected area clean and dry. Getting up every so often instead of sitting for a long time can also help prevent these cysts.