Skin melanocytic tumor

Melanoma

Nevoid melanoma



Last author update: 1 May 2013
Last staff update: 8 March 2022

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PubMed Search: Nevoid melanoma

Christopher S. Hale, M.D.
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Cite this page: Hale CS. Nevoid melanoma. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/skintumormelanocyticnevoidmelanoma.html. Accessed February 4th, 2023.
Definition / general
Terminology
  • Synonym: "verrucous pseudonevoid melanoma"
  • Distinct from controversial term "minimal deviation melanoma"
Epidemiology
Clinical features
  • Rare variant characterized by morphologic features of nevus
  • Behavior similar to other melanomas; may recur or metastasize causing death (Am J Dermatopathol 2001;23:167)
  • Key to diagnosis is high index of suspicion
  • Dome shaped papule, nodule or verrucous lesion
  • Tan nodule 1 cm or larger on trunk or proximal limbs of young adult
Case reports
Microscopic (histologic) description
  • Resembles ordinary compound or dermal nevus at low power, with symmetrical dome shaped or verrucous and papillomatous features, sharp lateral demarcation, inconspicuous junctional component and no pagetoid growth
  • High power shows relatively bland and monomorphic cells resembling classic nevus or epithelioid cells in Spitz nevus
  • Focal sheetlike growth pattern, nucleoli in tumor cells at base of lesion
  • Multiple dermal mitoses with atypical mitoses
  • Subtle pleomorphism and impaired maturation with depth
Microscopic (histologic) images

Images hosted on other servers:

Lesion #1:

Various images



Lesion #2:

Various images



Lesion #3:

Various images

Atypical single cells

Mitotic figures

Positive stains
Differential diagnosis
  • Melanoma arising in dermal nevus:
    • Residual nevus present, often tumor extension into deep reticular dermis and fat
  • Metastatic melanoma
  • Minimal deviation melanoma:
    • At most moderate atypia, at least level III due to dermal invasion, remnants of existing nevi usually present and usually few mitotic figures
  • Nodular melanoma:
    • High grade atypia, intraepidermal atypia
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