Dermoids and epidermoids are slow-growing benign cysts that typically occur in the scalp and the skull of infants and young children. These result from a part of the scalp, either the epidermis (top layer) or dermis (bottom layer), being misplaced underneath the scalp. This causes the formation of a small cyst filled with normal skin components.
Dermoids may contain hair, teeth, and skin glands. Epidermoids typically contain only epidermal tissue and keratin debris. These can occur anywhere on the head although they are most commonly found on the forehead, soft spot (anterior fontanel), or in the back of the head behind the ears.
The symptoms of epidermoid and dermoid tumors vary depending on their location. Cysts in the scalp are usually painless, moveable, rubbery masses that may slowly increase in size over time. The skin over the cyst is usually normal. Cysts in the bone may feel somewhat firmer and are usually less mobile. Although they usually only cause cosmetic problems, cysts in the skull may penetrate into the brain.
Most scalp lesions can be accurately diagnosed by physical exam and x-rays or other imaging may not be needed. Lesions that appear to involve the skull usually require skull x-rays or less commonly, a CT or MRI scan to make sure that there is no penetration into the brain.
Because of the potential to slowly enlarge and possibly penetrate through the skull, surgical removal is usually recommended. Most simple cysts can easily be removed with a short surgical procedure lasting less than an hour. Most children can go home the same day of surgery. Most children can resume regular activity, including bathing, in 2 to 3 days after surgery.
Page reviewed on: Nov 19, 2009
Page reviewed by: Susan R. Durham, MD, MS