Skin nonmelanocytic tumors
Adnexal tumors - hair follicles
Hair follicle nevus


Topic Completed: 1 June 2016

Revised: 14 March 2019

Copyright: 2001-2019, PathologyOutlines.com, Inc.

PubMed search: hair follicle nevus
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Cite this page: Elwood HR. Hair follicle nevus. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/skintumornonmelanocytichairfolliclenevus.html. Accessed March 20th, 2019.
Definition / general
  • Rare, congenital, hamartomatous proliferation of mature vellus hairs
  • Also known as congenital vellus hamartoma
Clinical features
  • Usually present at birth or early childhood
  • Solitary skin colored papule, less than 1 cm in greatest dimension
  • Sometimes with hypertrichosis
  • Most commonly on head and neck
  • Rarely multiple or arranged in a linear distribution, following the lines of Blaschko (J Am Acad Dermatol 2002;46:S125)
Case reports
Microscopic (histologic) description
  • Increased numbers of closely situated mature vellus hair follicles
  • Some are associated with small sebaceous glands or have thickened perifollicular fibrous sheaths
  • Follicles may be located abnormally high within the dermis
  • No cartilage (seen in accessory tragus), central cysts or a central canal (seen in trichofolliculoma)
Differential diagnosis
  • Accessory tragus: also has increased vellus hairs, but usually has other types of tissue (i.e. mature adipose tissue or cartilage); location around the ear is also helpful
  • Trichofolliculoma: has central cyst or canal; deeper levels may be necessary to find trichofolliculoma in a lesion that resembles hair follicle nevus
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