What Are the Most Common Types of Cyst?

What is a cyst?

A cyst is a dome-shaped lesion that contains fluid or semi-fluid material within a closed pocket of tissue. It can feel firm or fluctuant (unstable) and often causes the overlying skin to bulge outwards, causing it to appear as a lump. Cysts are a common occurrence and are mostly benign (non-cancerous).

There are many different types of cysts, and these can vary in appearance depending on their type and location. Cysts can form anywhere on the body – common sites include the face, scalp, upper arms, and back. Cysts can also develop in the genital region.

What do cysts look like?

Epidermoid cysts are the most common type of cysts. Usually found underneath the skin, they look like round, firm nodules that are flesh-coloured or yellowish in appearance. There may also be a central pore or punctum (a small distinct point) present. These cysts contain keratin, a soft, cheese-like material with a distinct odour.

Pilar cysts are common dermal cysts that typically form on the scalp. This type of cyst feels firm or hard to the touch, and there is usually no punctum seen. Pilar cysts occur mostly in middle-aged adults.

Types and causes of cysts

Each type of cyst has specific causes, and understanding these can help in effective diagnosis and treatment. Below, we will discuss what causes the formation of common cysts like acne cysts, sebaceous cysts, and ganglion cysts.

Acne cysts

Acne cysts, also known as cystic acne, are one of the most severe forms of acne.

Acne cysts typically develop when hair follicles or pores become blocked by a combination of excess sebum (an oily substance produced by sebaceous glands), dead skin cells, and bacteria. The blockage creates an ideal environment for bacteria to thrive, leading to inflammation and the formation of cysts.

Hormonal fluctuations, particularly during puberty, menstruation, or stress, can increase sebum production, making cystic acne more likely.

Genetics also play a role in determining an individual's susceptibility to developing acne cysts.

Poor skincare practices, such as not cleansing the face properly or using comedogenic (pore-clogging) products, can further contribute to their formation.

Sebaceous cysts

Sebaceous cysts, also known as epidermoid or epidermal inclusion cysts, are non-cancerous lumps that develop beneath the skin.

Sebaceous cysts typically form when a sebaceous gland, which produces sebum to lubricate hair and skin, becomes blocked. This blockage can be caused by trauma to the area, such as a cut or surgical wound, or a misshapen or damaged hair follicle. The trapped sebum builds up, creating a cyst.

Sebaceous cysts are most commonly found on the face, neck, and torso. They usually grow slowly and are generally painless, although they can become infected or inflamed, causing discomfort and requiring medical treatment.

Ganglion cysts

Ganglion cysts are non-cancerous lumps that typically develop along the tendons or joints of the wrists or hands, although they can also appear on the ankles or feet.

The exact cause of ganglion cysts is not well understood, but they are thought to arise from a weakness in the joint or tendon sheath. This weakness allows the joint or tendon fluid to leak out and accumulate, forming a cyst. Factors that may contribute to their development include joint or tendon irritation, repetitive movements, or trauma to the area. Ganglion cysts can vary in size and may cause discomfort or pain, especially if they press on nearby nerves. Treatment options range from observation and immobilization to aspiration or surgical removal if the cyst causes significant pain or interferes with joint function.

How are cysts treated?

Asymptomatic cysts do not require treatment. However, patients often opt to remove cysts if they are increasing in size or become infected and inflamed. A course of antibiotics may be needed if the cyst is inflamed.

In some cases, cysts are treated by making an incision and draining its contents. However, cysts may recur after this type of treatment.

The most common and effective way to remove a cyst is by cutting out the lesion entirely. It is a surgical procedure that is done under local anaesthesia, and patients receive stitches to close the incision after removal of the cyst. A specimen of the cyst can be sent for biopsy to confirm that it is benign. Patients may be able to claim the surgical expenses of this procedure from MediSave or insurance.