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Disease Profile


Prevalence estimates on Rare Medical Network websites are calculated based on data available from numerous sources, including US and European government statistics, the NIH, Orphanet, and published epidemiologic studies. Rare disease population data is recognized to be highly variable, and based on a wide variety of source data and methodologies, so the prevalence data on this site should be assumed to be estimated and cannot be considered to be absolutely correct.


US Estimated

Europe Estimated

Age of onset




D23.3 D23.4 D23.6


Autosomal dominant A pathogenic variant in only one gene copy in each cell is sufficient to cause an autosomal dominant disease.


Autosomal recessive Pathogenic variants in both copies of each gene of the chromosome are needed to cause an autosomal recessive disease and observe the mutant phenotype.


dominant X-linked dominant inheritance, sometimes referred to as X-linked dominance, is a mode of genetic inheritance by which a dominant gene is carried on the X chromosome.


recessive Pathogenic variants in both copies of a gene on the X chromosome cause an X-linked recessive disorder.


Mitochondrial or multigenic Mitochondrial genetic disorders can be caused by changes (mutations) in either the mitochondrial DNA or nuclear DNA that lead to dysfunction of the mitochondria and inadequate production of energy.


Multigenic or multifactor Inheritance involving many factors, of which at least one is genetic but none is of overwhelming importance, as in the causation of a disease by multiple genetic and environmental factors.


Not applicable


Other names (AKA)

Pilomatricoma; PTR; Calcifying epithelioma of Malherbe


Rare Cancers; Skin Diseases


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]


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.

Medical Terms Other Names
Learn More:
Percent of people who have these symptoms is not available through HPO
Somatic mutation


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]


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]

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]

Learn more

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.


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

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