Skin-Melanocytic tumor
Nevi
Congenital nevus

Reviewer: Christopher Hale, M.D. (see Authors page)

Revised: 5 April 2016, last major update November 2012

Copyright: (c) 2003-2016, PathologyOutlines.com, Inc.

PubMed Search: Congenital nevus [title]
General
  • See subtype: Giant congenital nevus

  • 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
  • 1-2% of newborns (Dermatology 2007;214:227), 17% of Italian children ages 12-17 years
  • Clinical Features
  • Usually larger than acquired nevi (6-15 mm); may grow rapidly
  • Often large, irregular in contour and pigmentation, hair bearing
  • Associated with higher number of common melanocytic nevi and family history of melanoma, but not with sun exposure (Br J Dermatol 2008;159:433)
  • May be associated with infantile hemangioma (J Am Acad Dermatol 2008;58:S16)
  • Proliferative nodules often p53+ (67%) and c-kit+ (97%), but are usually benign and may regress (Am J Surg Pathol 2004;28:1017)
  • Associated with nevus cells in lymph nodes (Am J Dermatopathol 2002;24:1)
  • Overall risk of melanoma is 0.7% (Br J Dermatol 2006;155:1)
  • Acral lesions resemble melanoma clinically
  • Case Reports
  • 3 month old infant with benign proliferative nodule (J Am Acad Dermatol 2008;59:518)
  • 6 month old infants with subsequent melanoma (Arch Pathol Lab Med 2003;127:e343, J Plast Reconstr Aesthet Surg 2009;62:96)
  • 2 year old girl with congenital panfollicular nevus associated with polydactyly (J Cutan Pathol 2007;34 Suppl 1:14)
  • 32 year old man with excised 8 cm scalp mass (Case of the Week #383)
  • 40 year old man with associated smooth muscle hamartoma (J Cutan Pathol 2008;35 Suppl 1:83)
  • 56 year old woman with halo congenital nevus and vitiligo (Australas J Dermatol 2008;49:229)
  • Treatment
  • Early surgical removal
  • Laser resurfacing in neonates (Br J Dermatol 2006;154:889)
  • May have rapid severe repigmentation after curettage and dermabrasion (Br J Dermatol 2007;156:1251)
  • Dermoscopy
  • Globules (83%), hypertrichosis (79%) and reticular networks (71%, Arch Dermatol 2007;143:1007)
  • Clinical Images

    Images hosted on other servers:

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    Breast skin, courtesy of Dr. Mark R. Wick

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    Reticular pattern and regular globules

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    Globular pattern and patchy network

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    Haloed globules

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    Target network and target globules

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    Various images

    Gross Images

    Images hosted on PathOut server:

    Case of the Week #383:

    Micro 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
  • Micro Images

    Images hosted on PathOut server:

    Case of the Week #383:



    Images hosted on other servers:

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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

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    Fig 1, 2: congenital nevus;
    Figure 3: melanoma in axillary node (inset: S100)

    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