Melanocytic nevus

Melanocytic nevus 

Updated: 07/01/2023

© Jun Wang, MD, PhD

General features
  • Congenital or acquired
  • Benign nested melanocytic proliferation
  • Most common melanocytic tumor
  • May recur with incomplete excision
  • Recurrent nevus ("persistent nevus") may resemble melanoma  
  • Risk factors
    • Sun exposure
    • Light skin
    • Family history
Clinical features
  • Macule (junctional) or papule/nodule (intradermal/compound)
  • Hyperpigmentation
  • Regular pigmentation, shape and border
Pathological features
  • Nests of melanocytes
  • Melanocytes decrease in size towards base of lesion
  • Classified according to location
Junctional: Nest at dermal epidermal junction
Intradermal: Nest within dermis
Compound: Both junctional and dermal components
  • Other types of melanocytic nevus
Molecular abnormalities
  • Acquired RAS/BRAF mutations
Marker
  • Positive: S100
  • Negative: cytokeratin
Dysplastic nevus
Management
  • Follow up
  • Removal


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