Dermoid Cyst (Other)

A dermoid cyst is a small sac lined by skin cells that becomes trapped beneath the surface before birth, at a place where areas of developing skin join together. As the trapped cells continue to shed and produce oils, the sac slowly fills and grows.

Besides the eyebrow, dermoid cysts are found on the scalp, forehead, bridge of the nose, chin, neck and along the midline of the body. They feel like a smooth, firm, painless lump under normal skin, sometimes attached to the bone beneath. Dermoid cysts are benign and are not caused by anything you did.

Dermoid cysts do not go away by themselves and tend to enlarge gradually. Removal is recommended to prevent them becoming more noticeable, rupturing after a knock, or becoming infected, and to confirm the diagnosis.

Cysts in certain positions, particularly on the midline of the scalp, nose or neck, can occasionally have a deeper extension. Your child's surgeon may arrange an ultrasound or MRI scan before surgery to check this and plan the safest approach. Otherwise the diagnosis is usually made on examination alone, and surgery is scheduled electively at a convenient time.

The operation is performed under a general anaesthetic, usually as day surgery. Local anaesthetic is added for comfort afterwards.

An incision is made over the cyst, placed along natural skin lines or within the hairline where possible to keep the scar as discreet as it can be. The cyst is carefully separated from the surrounding tissue and removed intact, as removing it whole reduces the chance of it coming back. Where the cyst sits in a small hollow in the bone, this is gently cleaned. The skin is closed with fine dissolving stitches and covered with skin glue or a dressing. The cyst is sent to the laboratory for confirmation.

Most children are comfortable with simple pain relief and return to normal activities within a few days. Swelling and bruising around the wound are normal and settle within a week or two.

Keep the wound dry for the first couple of days, then gentle washing is fine. Avoid rough play and contact sport for around two weeks. Scars fade gradually over many months and benefit from sun protection. Contact the team if there is fever, spreading redness or discharge from the wound. The wound and laboratory result are reviewed at a follow-up appointment.