Cysts are closed capsule or sac-like structures, typically containing a liquid, semisolid, or gaseous material, much like a blister. There are many types, such as acne cysts, ganglion cysts, and kidney cysts.

Cysts vary in size from microscopic to very large. Very large cysts can displace internal organs.

A cyst is not a regular part of the tissue where it occurs. It has a distinct membrane and is separate from nearby tissue. The outer, or capsular, portion of a cyst is known as the cyst wall.

This article looks at the different types of cysts, their causes and symptoms, and some treatment options.

A collage depicting different types of cysts.Share on Pinterest
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There are various different types of cysts.

Acne cysts

Cystic acne, or nodulocystic acne, is a severe type of acne in which the skin’s pores become blocked, leading to infection and inflammation.

Learn about cystic acne on the back.

Arachnoid cysts

The National Institute of Neurological Disorders and Stroke notes that arachnoid cysts develop between the arachnoid membrane and the brain or spinal cord. These cysts contain spinal fluid.

Arachnoid cysts may affect newborn babies. Doctors call these primary arachnoid cysts.

The arachnoid membrane covers the brain. During fetal development, it doubles up or splits to form an abnormal pocket of spinal fluid. In some cases, a doctor may need to drain the cyst.

Secondary arachnoid cysts develop as a result of head injury, tumors, or meningitis.

Baker’s cysts

Baker’s cysts are also known as popliteal cysts.

Some do not cause any symptoms. However, a person with a Baker’s cyst can experience:

  • knee pain
  • a lump behind the knee
  • a feeling of fullness behind the knee
  • swelling in the knee and lower leg
  • stiffness or tightness located at the back of the knee

Baker’s cysts usually develop due to a problem with the knee joint, such as arthritis or a cartilage tear.

Bartholin’s cysts

Bartholin’s cysts can occur if the ducts of the Bartholin gland, which are inside the vagina, become blocked.

A doctor may recommend surgery or prescription antibiotics as treatment.

Breast cysts

Breast cysts are common and may be painful.

In people assigned female at birth, these cysts can develop or change in size throughout the menstrual cycle, and they often disappear on their own. However, a doctor can drain the fluid if they are causing discomfort.

According to the American Cancer Society, simple cysts do not increase the risk of breast cancer. That said, there is a small chance that complex cysts may contain cancer or increase a person’s risk of cancer later on, depending on the results of a biopsy.

Read more about breast lumps.

Chalazion cysts

Very small eyelid glands, known as meibomian glands, make a lubricant that comes out of tiny openings in the edges of the eyelids. Cysts can form here if the ducts are blocked. These are known as chalazion cysts.

According to the National Health Service (NHS) in the United Kingdom, a doctor may prescribe antibiotics for a chalazion cyst.

Learn about styes.

Colloid cysts

Colloid cysts develop in the brain and contain gelatinous material.

Treatment depends on whether the cyst is causing symptoms or a buildup of fluid in the brain. A doctor may recommend surgery to remove the cyst or aspiration (draining).

Learn more about cysts in the brain.

Dentigerous cysts

Dentigerous cysts surround the crown of an unerupted tooth. It typically develops when a person is in their 20s and 30s, though it can happen at other times too.

Some people may require surgery to remove the cyst.

Dermoid cysts

Dermoid cysts comprise mature skin, hair follicles, sweat glands, and clumps of long hair, as well as fat, bone, cartilage, and thyroid tissue.

They can form anywhere on the body. A doctor may recommend surgically removing the cyst.

Learn more about dermoid cysts.

Epidermoid cyst

Epidermoid cysts contain keratin material and occur on the skin of the face, back, scalp, or scrotum.

A 2021 article notes that people may also refer to epidermoid cysts as “sebaceous cysts.” However, these cysts do not involve the sebaceous gland, and healthcare professionals call them epidermoid cysts instead.

Learn more about a cyst on the scrotum.

Epididymal cysts

Epididymal cysts, or spermatoceles, form in the vessels attached to the testes. They are benign and contain a fluid that is white and cloudy. They also contain sperm.

They rarely need treatment. However, treatment may be necessary if they cause pain or become too large.

Read more about testicle lumps.

Ganglion cysts

Ganglion cysts are small, benign cysts that form on or near a joint or covering of a tendon.

They usually develop on the wrist and hand but can also appear on the foot, ankle, or knee.

A doctor may recommend draining the cyst or surgery to remove it.

Learn how to remove a ganglion cyst.

Hydatid cysts

Hydatid cysts develop due to a relatively small tapeworm. These cysts form in the lungs or liver.

Treatment options include surgery and medication.

Learn more about liver cysts.

Kidney cysts

There are several types of kidney cysts, or renal cysts. They are usually harmless.

Solitary cysts contain fluids, sometimes including blood. Some are present at birth, while tubular blockages cause others.

People with renal vascular diseases may have cysts that form due to dilatation of the blood vessels.

Treatment for kidney cysts may not be necessary if they do not cause any symptoms. However, draining or surgery can help manage any symptoms that do occur.

Learn more about kidney cysts.

Ovarian cysts

Ovarian cysts are common in females who have regular periods. They form during ovulation.

The majority of ovarian cysts are benign and cause no symptoms. However, some can become so large that the abdomen protrudes.

Polycystic ovary syndrome (PCOS) refers to when the ovaries develop many small cysts.

A doctor may recommend surgery to remove the cyst if it grows large, causes pain, or does not go away in time.

Learn more about complex ovarian cysts.

Pancreatic cysts

Pancreatic cysts can occur when the cells of the pancreas are injured or inflamed. They can also occur when pancreatic enzymes leak and damage the tissue of the pancreas.

There are almost 20 types of pancreatic cysts. They can be cancerous or noncancerous. Treatment can depend on the type.

Learn about pancreatic cancer.

Periapical cysts

Periapical cysts are the most common type of odontogenic cysts, which are related to the formation and development of teeth.

These cysts usually develop due to inflammation of the pulp, pulp death, or tooth decay.

Doctors may recommend endodontic (root canal) therapy for periapical cysts.

Learn more about root canal treatment and what to expect.

Pilar cysts

Pilar cysts are also known as trichilemmal cysts. They are fluid-filled cysts that form from a hair follicle and usually develop on the scalp.

Radical surgical excision is the main treatment for pilar cysts.

Pilonidal cysts

Pilonidal cysts form in the skin near the tailbone or lower back, and they sometimes contain ingrown hair.

These cysts can grow in clusters, which sometimes creates a hole or cavity in the skin.

A person may not require treatment for the cyst unless an infection develops. A doctor may then drain the cyst and treat the infection.

Learn more about an ingrown hair cyst and how to treat it.

Pineal gland cysts

These are benign cysts that form in the pineal gland in the brain. According to a review from 2020, pineal gland cysts are common.

A person may not require surgery to remove the cyst unless it causes painful or bothersome symptoms.

Learn more about the pineal gland.

Tarlov cysts

Tarlov cysts — also known as perineural, perineurial, or sacral nerve root cysts — occur at the base of the spine and are filled with cerebrospinal fluid.

A doctor may recommend lifestyle changes to help manage pain due to a Tarlov cyst.

Learn more about cerebrospinal fluid.

Vocal fold cysts

There are two types of vocal fold cysts: mucus retention cysts and epidermoid cysts.

Vocal fold cysts can interfere with the quality of a person’s speech, sometimes causing their vocal cords to produce:

  • multiple tones simultaneously, known as diplophonia
  • breathy speech, or dysphonia
  • hoarseness

Treatment can include:

  • steroids
  • speech therapy
  • surgery

Learn more about vocal cord dysfunction.

View the slideshow below for pictures of cysts.

The signs and symptoms of cysts vary widely depending on what type of cyst it is.

Skin cysts can cause symptoms such as:

  • a lump under the skin
  • fluid or pus in the lump
  • pain
  • redness or discoloration

Many internal cysts, such as those that occur in the kidneys or the liver, may not cause any symptoms at all. A person may not notice them until they show up on an imaging scan, such as an MRI, CT, or ultrasound scan.

It is unusual for some cysts, such as skin cysts, to cause pain unless they rupture, become infected, or are inflamed. However, breast cysts can cause pain.

A person may also experience headaches and other symptoms if a cyst develops on the brain.

Cysts can occur anywhere on the body. There are numerous possible causes, including:

  • infections
  • clogged sebaceous glands
  • tumors
  • genetic conditions
  • a fault in an organ of a developing embryo
  • a defect in the cells
  • chronic inflammatory conditions
  • blockages of ducts in the body that cause fluids to build up
  • a parasite
  • an injury that breaks a vessel

Cysts are usually benign and develop due to blockages in the body’s natural drainage systems.

However, some cysts can be malignant, or cancerous.

Anyone with any concerns about a cyst should consider contacting a doctor.

Learn about the differences between a cyst and a tumor.

The treatment options for a cyst will depend on a range of factors, including the type of cyst, where it is, its size, and the degree of discomfort it is causing.

For very large cysts that are causing symptoms, a doctor may recommend surgical removal.

Sometimes, a doctor can drain, or aspirate, the cyst by inserting a needle or catheter into the cavity. If the cyst is not easily accessible, they may use radiologic imaging to accurately guide the needle or catheter.

Learn more about aspiration.

Although cysts and boils can appear similar in appearance, their causes and treatment options are different.

A cyst is a closed sac that consists of liquid, gaseous, or semisolid material.

A boil is a lump that has filled with pus and develops around hair follicles. They usually occur as a result of a bacterial infection.

Learn more about cysts and boils.

Here are some frequently asked questions about cysts.

What size ovarian cyst requires surgery?

Whether a doctor recommends surgery depends on the size of the cyst, a person’s age, and if signs of malignancy are present.

A doctor will recommend surgery to remove an ovarian cyst if it is very large, continues to grow, or is causing symptoms.

Usually, cysts less than 10 centimeters are benign and, providing they are not causing any symptoms, only require watchful waiting.

What makes an ovarian cyst suspicious?

A healthcare professional may request a further evaluation if the cyst measures more than 10 cm and is complex. Complex cysts are filled with either blood or hard substances.

How do doctors know if an ovarian cyst is cancerous?

Doctors use imaging tests, such as an ultrasound, to help determine if an ovarian cyst is cancerous. They may also perform a laparoscopy to get a sample for a biopsy.

Do cysts go away on their own?

Some cysts may go away on their own. However, if a cyst does not go away or grows larger, it may require treatment, such as surgery to remove it or aspiration.

How serious is a cyst?

Many cysts are benign, and they may not cause any symptoms. A person may not know they have a cyst, and the cyst may go away on its own. However, some cysts can be cancerous, so it is best to contact a doctor as soon as a person has concerns about a cyst.

Cysts are fluid-filled sacs that can develop in tissues in any part of the body. They are relatively common, and there are many different types.

Infections, tumors, parasites, and injuries can cause cysts. They are usually benign, but sometimes, they can be cancerous.

If a person has concerns about a cyst or has noticed a new lump, it is best to contact a doctor for an accurate diagnosis and treatment.