Skin - Nonmelanocytic tumors
Benign (nonmelanotic) epidermal tumors or tumor-like lesions
Epidermal nevus

Author: Hillary Rose Elwood, M.D.(see Authors page)

Revised: 13 October 2016, last major update May 2016

Copyright: (c) 2003-2016, PathologyOutlines.com, Inc.

PubMed Search: Epidermal nevus [title]
Cite this page: Epidermal nevus. PathologyOutlines.com website. http://pathologyoutlines.com/topic/skintumornonmelanocyticepidermalnevus.html. Accessed March 27th, 2017.
Definition / General
  • Benign, congenital, hamartomatous malformation of epidermal cells
  • Other types of epidermal nevi exist, consisting of malformation of adnexal epithelium, sometimes termed “organoid type” of epidermal nevus (see nevus sebaceus)
Clinical Features
  • 1 - 3 per 1000 live births, males = females, usually congenital, sometimes appears in children later in life
  • Usually presents as localized verrucous papules to plaques, often on the extremities, trunk, head and neck
  • Other presentations are possible, with linear, one-sided, and extensive variants described
  • Most often a localized and incidental finding but may also present with extracutaneous abnormalities or may be seen in association with one of multiple syndromes (e.g. KID, CHILD, Gardners, etc)
  • Epidermal nevus syndrome
    • Association of epidermal nevus with skeletal, neurologic, ophthalmic abnormalities
Case Reports
Micro Description
  • Hyperkeratosis with broad low papillomatosis and acanthosis
  • Pathology often identical to papillomatous seborrheic keratosis
  • Can have slight increase in basal melanin pigment
  • Sometimes epidermolytic hyperkeratosis is present within the lesion
  • Numerous rare histologic patterns have been described within epidermal nevi such as acanthosis - nigricans - like, hailey - hailey - like, acantholytic dyskeratosis, others
Micro Images

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Typical histologic features of hyperkeratosis, acanthosis, and papillomatosis

Differential Diagnosis
  • Acanthosis nigricans: Usually has less hyperkeratosis and papillomatosis than typically seen in epidermal nevus, but there are acanthosis nigricans-like variants of epidermal nevus
  • Confluent and reticulated papillomatosis of Gougerot and Carteaud (CARP): Papillomatous architecture usually more subtle and sometimes absent
  • Epidermal nevus can resemble other proliferations with papillomatous epidermal architecture, and clinical information is often necessary to make the distinction
  • Seborrheic keratosis: Often has identical histology; Consider an epidermal nevus if a lesion resembles a seborrheic keratosis but is in a child or young individual, or is described as a congenital lesion
  • Verruca vulgaris