Vulva, vagina & female urethra

Melanocytic lesions

Dysplastic nevi

Last author update: 1 August 2016
Last staff update: 6 September 2023 (update in progress)

Copyright: 2002-2023,, Inc.

PubMed Search: Dysplastic nevi [title]

Sarah Strickland, M.D.
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Cite this page: Strickland S. Dysplastic nevi. website. Accessed September 26th, 2023.
Essential features
  • Also called atypical nevus, nevus with architectural disorder, Clark nevus
  • Any site; no predilection for anogenital skin
  • At sites with minimal sun exposure (breast, buttocks) and sun exposed areas
  • Genital lesions arise mainly on labia majora, labia minora, clitoris
  • May occur on perineum, pubic region, male genitalia
Clinical features
  • Biopsy / excision and histological examination
Prognostic factors
Case reports
  • Excision
Clinical images

Images hosted on other servers:

Examples of dysplastic nevi
defined based on clinical criteria

Microscopic (histologic) description
  • Basilar proliferation of atypical melanocytes which must extend at least three rete ridges beyond the dermal component
  • Lentiginous or epithelioid cell pattern proliferation
  • Elongation and bridging of the rete ridges
  • Variable cellular atypia
  • Concentric eosinophilic or lamellar fibroplasia
  • Lymphocytic infiltrate
  • Vascular ectasia
Microscopic (histologic) images

Images hosted on other servers:

Low magnification micrograph of a dysplastic nevus

Intermediate magnification micrograph of a dysplastic nevus

High magnification micrograph of a dysplastic nevus

Virtual slides

Images hosted on other servers:

Dysplastic nevus
with severe superficial

Dysplastic nevus
with slight cytologic

Dysplastic nevus
with inflammation
and regression

Positive stains
Differential diagnosis
  • Atypical melanocytic nevus of genital type:
    • Large, variably sized juncional nests with prominent retraction artifact or cellular dyscohesion
    • Nondescript pattern of dermal fibrosis
    • Underlying “mushroom shaped” dermal component with maturation
  • Melanoma:
    • Asymmetric
    • Irregular thickening and thinning of the epidermis
    • Uniform cytologic atypia
    • Increased pigment incontinence
    • Lack of maturation of cells in the dermis
    • Dermal mitotic figures
    • Pagetoid proliferation of melanocytes
Additional references
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