Pilomatrixoma in Children What is a pilomatrixoma?A pilomatrixoma (PEE-lo-may-trick-SO-mah) is a slow-growing, hard lump found under the skin. It is most common on the face and neck, but it may be on other parts of the body. A pilomatrixoma is usually a single lump, but occasionally, there may be more than one. Pilomatrixomas are more common in children and young adults than in older adults. What causes a pilomatrixoma? Doctors don't know the exact cause of pilomatrixomas. They develop when cells harden and form a lump under the skin. The cells are similar to hair follicle cells. Pilomatrixomas may be more common in some families. They may also happen with conditions that are inherited (genetic syndromes). What are the symptoms of a pilomatrixoma? Here are the most common symptoms of a pilomatrixoma: A small, hard lump beneath the skin, usually on the face or neck The skin covering the lump looks normal The mass is usually painless, unless it becomes infected The symptoms of a pilomatrixoma can be like other health conditions. Make sure your child sees his or her healthcare provider for a diagnosis. How is a pilomatrixoma diagnosed? A pilomatrixoma is usually diagnosed based on how it looks. Diagnostic tests may include: Biopsy. A sample of tissue is taken and looked at under a microscope. Imaging. X-ray, ultrasound, CT scan, or MRI may be done, but not always. How is a pilomatrixoma treated?Treatment may include surgery to cut out the lump. Covering the area with skin from another part of the body may be needed, depending on the size of the lump. What are the complications of a pilomatrixoma?Most children do not face any serious complications. But pilomatrixomas can become cancerous in rare cases. Pilomatrixomas can also come back after they are removed. When should I call my child’s healthcare provider?Call your child’s healthcare provider if you notice any skin lumps or masses. Key points about pilomatrixomas A pilomatrixoma is a slow-growing, hard lump under the skin. It is most common on the face and neck. Doctors don't know the exact cause of pilomatrixomas. Treatment may include surgery to remove the lump. Next stepsTips to help you get the most from a visit to your child’s healthcare provider: Before your visit, write down questions you want answered. At the visit, write down the names of new medicines, treatments, or tests, and any new instructions your provider gives you for your child. If your child has a follow-up appointment, write down the date, time, and purpose for that visit. Know how you can contact your child’s provider after office hours. This is important if your child becomes ill and you have questions or need advice. Medical Reviewers: Berry, Judith, PhD, APRN Holloway, Beth, RN, M.Ed.