Skin Lesions: Dermoid Cysts and Pilomatrixoma

A dermoid cyst is a collection of skin cells trapped under the skin surface. They are common in the head and neck area commonly above the outer angle of eye or the midline of the neck. They tend to gradually increase in size and occasionally get infected. Rupture can happen occasionally when the child gets knocked against a firm surface.

A pilomatrixoma (‘pilomatricoma’ or ‘calcifiying epithelioma of Malherbe’) is a slow-growing, non-cancerous tumour of the hair follicle. It usually occurs in the face or neck but can occur anywhere in the body. They are usually 5-10mm in diameter, hard to touch, can be tender and occur as a single lump. Occasionally there can be more than one.

How are dermoid cysts & pilomatrixomas treated?

Dermoid cysts and pilomatrixomas do not go away on their own and they are best treated with surgery. The aim of the operation is complete removal of the lesion. The operation is usually performed under general anaesthesia. Your child will usually not have to stay overnight in hospital.

Preoperative Preparation

Your child cannot eat for 6 hours before the procedure. In breast fed babies this time may be reduced by the anaesthetist. Your child can drink water for up to 2 hours before the operation. The Day Surgery Unit will instruct you the day before surgery to confirm fasting times. It is useful to bring your child’s favourite toy along on the day.


The operation is done through an elliptical skin incision around the dermoid cyst or pilomatrixoma. The lesion is completely removed, and the skin is closed with absorbable sutures. Local anaesthetic is injected to numb the area. Tissue glue is applied as a dressing. It is lilac in colour and takes 2 weeks to fall away. The whole operation takes around 20 minutes.

Initial recovery

On completion of the operation your child will be taken to the recovery area. Children often initially appear distressed and a little confused upon waking up but will quickly settle down once you are with them and if offered a drink or something to eat. Full recovery usually takes about 2-3 hours after which you can go home.

Post-operative course

Children’s paracetamol can be given for pain relief for 24 hours. After that use paracetamol only if needed. Some children need additional medication such as ibuprofen or celecoxib. Opiate (morphine-type) medications are not usually required. Paracetamol and ibuprofen can be given at the same time and work well together. Follow the dosages recommended on the packaging or by the anaesthetist. Never give more than has been prescribed.

It is quite normal for there to be a little bruising around the wound. This usually resolves in week or so.

In general, your child may eat a normal diet after surgery. Vomiting is common on the day of surgery. It is temporary, and usually due to the anaesthetic and pain-relief medications that are used. If vomiting occurs, start with clear liquids and add solids slowly for the first day.

Return to activity

  • Activity: Your child should avoid strenuous activity first 1-2 days. Sport and swimming are best avoided for 3 weeks after surgery.
  • School: Your children may return to day care or school when comfortable.
  • Bathing/showering: As the wound is waterproof, bathing and showering is safe after the operation.
  • Wound care: No specific wound care is required. The stitches are absorbable and do not require removal. No dressing changes, creams or ointments are required.
  • Stool softeners and laxatives: May be needed to help regular stooling after surgery, especially if opiates are needed for pain.
Call the doctor’s office if:
  • You see any signs of infection: redness along the incision site, increased swelling, discharge
  • Your child’s pain gets worse or is not relieved by pain killers
  • There is bleeding from the incision
  • Your child has an abnormal temperature
  • Vomiting continues on the day after surgery
  • If you have any other concerns


I will review your child 4-6 weeks after the surgery to ensure healing of the wound. For patients from rural areas this may be deferred to your local General Practitioner or Paediatrician. Please ring soon after the operation to arrange a convenient time.


This is a common operation with a low complication rate. The vast majority of children who have this operation recover well and have no serious complications of surgery. However, complications can occur. Some of the recognised ones include:

Infection & Bleeding
There is a 1-2% risk of bleeding or wound infection after surgery. The wound will appear red, be tender to touch and may discharge pus or blood. If this occurs, a course of antibiotics may be required, and you should contact me or present to your General Practitioner or Local Hospital as soon as possible.

More Information

If you have any questions, please do not hesitate to contact us.

Ph: 02 8307 0977
Fax: 02 8088 7420

Please refer to the following resources for more information:

  1. Pilomatricoma
    DermNet NZ
  2. Dermoid Cyst
    Children's Hospital of Philadelphia

This page is intended to provide you with information and does not contain all known facts about dermal cysts and pilomatrixoma. Treatment may have uncommon risks not discussed here. Please do not hesitate to ask any questions you may have.