National Center for Advancing and Translational Sciences Genetic and Rare Diseases Information Center, a program of the National Center for Advancing and Translational Sciences

Pilomatrixoma


Other Names:
Pilomatricoma; PTR; Calcifying epithelioma of Malherbe
Categories:
Pilomatrixoma is a benign (non-cancerous) skin tumor of the hair follicle (structure in the skin that makes hair). They tend to develop in the head and neck area and are usually not associated with any other signs and symptoms (isolated). Rarely, pilomatrixomas can become cancerous (known as a pilomatrix carcinoma). Although they can occur in people of all ages, pilomatrixomas are most commonly diagnosed in people under age 20. The exact underlying cause is not well understood; however, somatic changes (mutations) in the CTNNB1 gene are found in most isolated pilomatrixomas. Rarely, pilomatrixomas occur in people with certain genetic syndromes such as Gardner syndrome, myotonic dystrophy, and Rubinstein-Taybi syndrome; in these cases, affected people usually have other characteristic signs and symptoms of the associated condition. They are usually treated with surgical excision.[1][2][3]
Last updated: 1/23/2015

This table lists symptoms that people with this disease may have. For most diseases, symptoms will vary from person to person. People with the same disease may not have all the symptoms listed. This information comes from a database called the Human Phenotype Ontology (HPO) . The HPO collects information on symptoms that have been described in medical resources. The HPO is updated regularly. Use the HPO ID to access more in-depth information about a symptom.

Showing of 4 |
Medical Terms Other Names
Learn More:
HPO ID
Percent of people who have these symptoms is not available through HPO
Autosomal dominant inheritance 0000006
Neoplasm of the skin
Skin tumors
Tumor of the skin
[ more ] 		0008069
Pilomatrixoma 0030434
Somatic mutation 0001428
Showing of 4 |
Last updated: 7/1/2020
The exact underlying cause of pilomatrixoma is not well understood. Changes (mutations) in the CTNNB1 gene are found in at least 75% of isolated (without other signs and symptoms) pilomatrixomas. These mutations are somatic, which means they are not inherited and are only present in the tumor cells. The CTNNB1 gene encodes a protein that is needed to regulate cell growth and attachment. When the gene is not working properly, it can result in abnormal cell growth.[2][3]

Rarely, pilomatrixomas occur in people with certain genetic syndromes such as Gardner syndrome, myotonic dystrophy, and Rubinstein-Taybi syndrome. In these cases, affected people usually have other characteristic features of the associated condition.[2][3]
Last updated: 1/22/2015
Most isolated (without other signs and symptoms) pilomatrixomas are not inherited. However, more than one family member can rarely be affected, which suggests there may be a hereditary component in some cases.[2][3]

Rarely, pilomatrixomas occur in people with certain genetic syndromes such as Gardner syndrome, myotonic dystrophy, and Rubinstein-Taybi syndrome. In these cases, affected people usually have other characteristic signs and symptoms of the associated condition. All three of these conditions are inherited in an autosomal dominant manner. In some cases, an affected person inherits the mutation from an affected parent. Other cases may result from new (de novo) mutations in the gene. These cases occur in people with no history of the disorder in their family.[2][3]
Last updated: 1/23/2015
A diagnosis of pilomatrixoma is usually suspected on physical examination. Specialized tests may be ordered to confirm the diagnosis and rule out other conditions that cause similar features. These tests may include an ultrasound, an X-ray, and/or a small biopsy of the tumor.[1][2]
Last updated: 1/23/2015

Testing Resources

  • The Genetic Testing Registry (GTR) provides information about the genetic tests for this condition. The intended audience for the GTR is health care providers and researchers. Patients and consumers with specific questions about a genetic test should contact a health care provider or a genetics professional.
Pilomatrixomas are usually surgically removed (excised). In most cases, the tumors do not grow back (recur) after surgery, unless the removal was incomplete.[2][1]
Last updated: 1/23/2015
The long-term outlook (prognosis) for people with an isolated (without other signs and symptoms) pilomatrixoma is usually good. Most people do not experience any serious complications, although pilomatrixomas can become cancerous (known as a pilomatrix carcinoma) in rare cases. When surgically removed, pilomatrixomas typically do not grow back (recur), unless the excision was incomplete.[1][2][3]

Rarely, pilomatrixomas occur in people with certain genetic syndromes such as Gardner syndrome, myotonic dystrophy, and Rubinstein-Taybi syndrome.[2][3] In these cases, the prognosis varies based on the condition and its associated symptoms.
Last updated: 1/23/2015

If you need medical advice, you can look for doctors or other healthcare professionals who have experience with this disease. You may find these specialists through advocacy organizations, clinical trials, or articles published in medical journals. You may also want to contact a university or tertiary medical center in your area, because these centers tend to see more complex cases and have the latest technology and treatments.

If you can’t find a specialist in your local area, try contacting national or international specialists. They may be able to refer you to someone they know through conferences or research efforts. Some specialists may be willing to consult with you or your local doctors over the phone or by email if you can't travel to them for care.

You can find more tips in our guide, How to Find a Disease Specialist. We also encourage you to explore the rest of this page to find resources that can help you find specialists.

Healthcare Resources

Research helps us better understand diseases and can lead to advances in diagnosis and treatment. This section provides resources to help you learn about medical research and ways to get involved.

Clinical Research Resources

  • ClinicalTrials.gov lists trials that are related to Pilomatrixoma. Click on the link to go to ClinicalTrials.gov to read descriptions of these studies.

    Please note: Studies listed on the ClinicalTrials.gov website are listed for informational purposes only; being listed does not reflect an endorsement by GARD or the NIH. We strongly recommend that you talk with a trusted healthcare provider before choosing to participate in any clinical study.

These resources provide more information about this condition or associated symptoms. The in-depth resources contain medical and scientific language that may be hard to understand. You may want to review these resources with a medical professional.

Where to Start

  • DermNet NZ is an online resource about skin diseases developed by the New Zealand Dermatological Society Incorporated. DermNet NZ provides information about this condition.
  • Genetics Home Reference (GHR) contains information on Pilomatrixoma. This website is maintained by the National Library of Medicine.

In-Depth Information

  • Medscape Reference provides information on this topic. You may need to register to view the medical textbook, but registration is free.
  • The Monarch Initiative brings together data about this condition from humans and other species to help physicians and biomedical researchers. Monarch’s tools are designed to make it easier to compare the signs and symptoms (phenotypes) of different diseases and discover common features. This initiative is a collaboration between several academic institutions across the world and is funded by the National Institutes of Health. Visit the website to explore the biology of this condition.
  • Online Mendelian Inheritance in Man (OMIM) is a catalog of human genes and genetic disorders. Each entry has a summary of related medical articles. It is meant for health care professionals and researchers. OMIM is maintained by Johns Hopkins University School of Medicine. 
  • Orphanet is a European reference portal for information on rare diseases and orphan drugs. Access to this database is free of charge.
  • PubMed is a searchable database of medical literature and lists journal articles that discuss Pilomatrixoma. Click on the link to view a sample search on this topic.

Questions sent to GARD may be posted here if the information could be helpful to others. We remove all identifying information when posting a question to protect your privacy. If you do not want your question posted, please let us know. Submit a new question

  • My son had four pilomatrixomas removed a few years ago. Recently, a new one developed. Is it normal for new ones to develop? Will this happen to him for the rest of his life? Does bumping the area have anything to do with him developing a pilomatrixoma? See answer

  • What causes pilomatrixomas? See answer


  1. Pilomatricoma. DermNet NZ. December 2014; http://www.dermnetnz.org/lesions/pilomatricoma.html.
  2. Rao J. Pilomatrixoma. Medscape Reference. March 3, 2014; http://emedicine.medscape.com/article/1058965-overview#a0104. Accessed 3/9/2015.
  3. Pilomatricoma. Genetics Home Reference. June 2012; http://ghr.nlm.nih.gov/condition/pilomatricoma.