GTR Home > Conditions/Phenotypes > Epidermal nevus


Epidermal nevi are congenital lesions that affect about 1 in 1,000 people. They appear at or shortly after birth as localized epidermal thickening with hyperpigmentation that frequently follow the lines of Blaschko, suggesting that they result from postzygotic somatic mutation in the skin (Paller et al., 1994). A rare subgroup of epidermal nevi is clinically indistinguishable from other epidermal nevi, but displays histopathologic features typical of epidermolytic hyperkeratosis (see EHK, 113800), and patients with this type of epidermal nevi sometimes have offspring with generalized EHK (Paller et al., 1994). See giant pigmented hairy nevus (137550) and malignant melanoma (155600). Nevus sebaceous is a benign congenital skin lesion that preferentially affects the scalp and face. It occurs in about 1 in 1,000 live births and is characterized by hairless, yellow-orange plaques of various size and shape. Histology shows that nevus sebaceous is a hamartoma consisting of epidermal, sebaceous, and apocrine elements. About 24% of nevi develop secondary tumors, some of which may be malignant (summary by Groesser et al., 2012). [from OMIM]

Associated genes

  • Also known as: ACH, CD333, CEK2, HSFGFR3EX, JTK4, FGFR3
    Summary: fibroblast growth factor receptor 3

  • Also known as: C-BAS/HAS, C-H-RAS, C-HA-RAS1, CTLO, H-RASIDX, HAMSV, HRAS1, RASH1, p21ras, HRAS
    Summary: Harvey rat sarcoma viral oncogene homolog

  • Also known as: RP5-1000E10.2, ALPS4, CMNS, N-ras, NCMS, NRAS1, NS6, NRAS
    Summary: neuroblastoma RAS viral (v-ras) oncogene homolog

  • Also known as: CLOVE, CWS5, MCAP, MCM, MCMTC, PI3K, p110-alpha, PIK3CA
    Summary: phosphatidylinositol-4,5-bisphosphate 3-kinase, catalytic subunit alpha

Clinical features

  • Numerous nevi
  • Melanocytic nevus

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