Cutaneous cysts and pseudocysts

Author: Dr Amanda Oakley, Dermatologist, Hamilton, New Zealand, 1997. Updated February 2016.

What is a cyst?

A cyst is a benign, round, dome-shaped encapsulated lesion that contains fluid or semi-fluid material. It may be firm or fluctuant and often distends the overlying skin. There are several types of cyst. The most common are described here.

What is a pseudocyst?

Cysts that are not surrounded by a capsule are better known as pseudocysts. These commonly arise in acne. 

Who gets cysts?

Cysts are very common, affecting at least 20% of adults. They may be present at birth or appear later in life. They arise in all races. Most types of cyst are more common in males than in females.

What causes cysts?

The cause of many cysts is unknown.

What are the clinical features of cysts?

Epidermoid cyst

Epidermoid cyst is also called follicular infundibular cyst, epidermal cyst, keratin cyst.

More images of epidermoid cysts ...

Trichilemmal cyst

A trichilemmal cyst is also called pilar cyst.

More images of epidermoid cysts ... 

Steatocystoma

Eruptive vellus hair cysts

Dermoid cyst

Ganglion cyst

More images of digital myxoid pseudocysts ...

Labial mucous/myxoid cyst

Hidrocystoma

More images of hidrocystoma of eyelid ...

Milium/milia

More images of milia ...

Vulval mucous cyst

Comedo and acne pseudocyst

Pseudocyst of auricle

 

Complications of cysts

Rupture of a cyst

Secondary infection

Pressure effect

Malignancy

How are cysts diagnosed?

Cysts are usually diagnosed clinically as they have typical characteristics. When a cyst is surgically removed, it should undergo histological examination. The type of lining of the wall of cyst and the cyst contents help the pathologist classify it.

What is the treatment for cysts?

Asymptomatic epidermoid cysts do not need to be treated. In most cases, attempt to remove only the contents of a cyst is followed by recurrence. If desired, cysts may be fully excised. Recurrence is not uncommon, and re-excision may be surgically challenging.

Inflamed cysts are sometimes treated with:

How can cysts be prevented?

Unknown.

What is the outlook for cysts?

Cysts generally persist unless surgically removed.

Related information

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