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Genetic and Rare Diseases Information Center (GARD)

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Pilomatrixoma


Other Names for this Disease

  • Calcifying epithelioma of Malherbe
  • Epithelioma calcificans of Malherbe
  • Pilomatricoma
  • PTR
See Disclaimer regarding information on this site. Some links on this page may take you to organizations outside of the National Institutes of Health.

Overview

What is a pilomatrixoma?

What causes a pilomatrixoma?

Is a pilomatrixoma inherited?

How is a pilomatrixoma diagnosed?

How might a pilomatrixoma be treated?

What is the long-term outlook for people with a pilomatrixoma?

What is a pilomatrixoma?

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

What causes a pilomatrixoma?

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

Is a pilomatrixoma inherited?

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

How is a pilomatrixoma diagnosed?

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

How might a pilomatrixoma be treated?

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

What is the long-term outlook for people with a pilomatrixoma?

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

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


Other Names for this Disease
  • Calcifying epithelioma of Malherbe
  • Epithelioma calcificans of Malherbe
  • Pilomatricoma
  • PTR
See Disclaimer regarding information on this site. Some links on this page may take you to organizations outside of the National Institutes of Health.