Skin melanocytic tumor
Nevi
Nevus with features of congenital onset


Topic Completed: 1 November 2012

Minor changes: 11 September 2020

Copyright: 2003-2020, PathologyOutlines.com, Inc.

PubMed Search: Congenital nevus [title]

Related topics: Giant congenital nevus

Christopher S. Hale, M.D.
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Cite this page: Hale CS. Nevus with features of congenital onset. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/skintumormelanocyticcongenitalnevus.html. Accessed September 29th, 2020.
Definition / general
  • Most rigidly definition is nevi present at birth
  • Disagreement regarding whether nevi presenting very early in life but not at birth can be considered congenital (Acta Derm Venereol 2012;92:586)
  • In practice, nevi often labeled congenital if they have "congenital features" of melanocytes clustered around follicles, adnexae, nerves and between collagen fibers at base of lesion
  • References: eMedicine, J Am Acad Dermatol 2012;67:495.e1
Terminology
  • Agminate / agminated nevus: nevi that are "clustered", and may be confined to a developmental segment (J Invest Dermatol 2011;131:788)
  • Nevus spilus / speckled lentiginous nevus: common type of agminate nevus with multiple pigmented macules or papules within a pigmented patch (Cutis 2007;80:465)
  • Neuronevus: compound nevi with prominent neural features, Masson's neuronevus (cellular blue nevus with neural / schwannian differentiation) or congenital nevus with prominent neural features
  • Giant congenital nevus: see below
Epidemiology
Clinical features
Case reports
Treatment
Dermoscopy
Clinical images

Contributed by Mark R. Wick, M.D.
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Breast skin



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Reticular pattern and regular globules

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Globular pattern and patchy network

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Haloed globules (3)

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Target network and target globules (4 and 5)

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Congenital nevus

Gross images

Case #383

Partial black discoloration

Microscopic (histologic) description
  • Tends to involve reticular dermis, subcutis, skin adnexa, arrector pili muscles and nerves with single cell permeation of collagen
  • Also neural differentiation with Wagner-Meissner-like corpuscles
  • Frequent proliferative nodules
  • Lesions of infants may have pagetoid melanocytic proliferation
  • Proliferative nodules:
    • Dermal nodules of large epithelioid or spindled melanocytes that merge with surrounding nevus cells
    • Often prominent nucleoli, cellular areas, focal hemorrhage and ulceration but no necrosis, no destructive growth, minimal inflammation and 0 - 4 mitotic figures/10 HPF
    • Lesions mature and regress over time
Microscopic (histologic) images

Case #383



Various images



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Symmetrical broad proliferation of melanocytes
in papillary and reticular dermis with maturation,
splaying between collagen bundles, permeation of
muscles of hair erection, blood vessels, adnexa

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Deep congenital nevus

Molecular / cytogenetics description
  • Lesions present at birth usually have NRAS but not BRAF mutations
  • Lesions with congenital type histologic features but not present at birth more commonly have BRAF but not NRAS mutations (J Invest Dermatol 2007;127:179)
  • Germline Melanocortin-1-Receptor (MC1R) genotype is associated with severity of cutaneous phenotype in congenital melanocytic nevi (J Invest Dermatol 2012;132:2026)
Differential diagnosis
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