Definition: An epidermal cyst is also known as a sebaceous cyst. It is a collection of keratin-like material - usually white, cheesy, or firm - contained in a cyst wall. The epidermal cyst normally has a small opening that communicates with the skin and may not be very well seen. Epidermal cysts can occur on any skin surface, but are most common on the face, back or base of the ears, chest, and back.
Epidermal cysts do not have to be removed unless they are cosmetically unacceptable or if they get infected. An infected epidermal cyst is red, swollen, and painful. It should be treated with antibiotics and then excised when it is not inflamed. The key to removing an epidermal cyst is removing all of the cyst wall, otherwise the likelihood of the cyst coming back is high.
