Skin-Melanocytic tumor
Nevi
Giant congenital nevus

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

Revised: 5 April 2016, last major update November 2012

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PubMed Search: Giant congenital nevus
Cite this page: Giant congenital nevus. PathologyOutlines.com website. http://pathologyoutlines.com/topic/skintumormelanocyticgiantcongenitalnevus.html. Accessed January 23rd, 2018.
Definition / general
  • See: Congenital nevus

  • Congenital melanocytic nevi diameter > 20 cm (J Cutan Pathol 2010;37:764)
  • Terminology
  • Also called giant pigmented nevus or giant hairy nevus
  • Epidemiology
  • 1 in 500,000 live births (Br J Dermatol 1981;104:307)
  • ~2.5% risk of malignant transformation, usually before adolescence (Br J Dermatol 2006;155:1); may give rise to cutaneous or CNS melanoma or related neuroectodermal tumors (malignant peripheral nerve sheath tumor, cutaneous malignant melanotic neurocristic tumor, rhabdomyosarcoma, liposarcoma)
  • May contain pseudotumoral proliferative nodules that ulcerate (J Cutan Pathol 2010;37:764)
  • May have satellite nevi, including within mucosal membranes
  • Truncal nevi may develop symptomatic neurocutaneous melanosis (meningeal or cerebral melanosis), lethal in 1/3 (J Am Acad Dermatol 2006;54:767)
  • Sites
  • Dermatomal, "bathing suit" or "garment" configuration; may involve entire scalp, extremity, most of trunk or placenta
  • Scalp lesions are often in thickened folds of skin resembling cerebrum, may involute in first 2 years of life (J Am Acad Dermatol 2008;58:508)
  • Case reports
  • Newborn with neurocutaneous melanosis (J Neuroradiol 2007;34:272)
  • Neonate with nevus sebaceus of scalp and limbal dermoid on left eye (J Am Acad Dermatol 2008;58:884)
  • Neonate with extensive proliferative nodules (Clin Exp Dermatol 2008;33:125)
  • Girl with ulcerated and sclerotic lesion (Clin Exp Dermatol 2007;32:529)
  • Desmoplastic lesion with progressive depigmentation (J Am Acad Dermatol 2007;56:S10)
  • Treatment
  • Possibly none for newborn scalp lesions
  • Excision may require careful planning and several stages (Plast Reconstr Surg 2008;121:1674)
  • Often split-thickness skin grafting (Ann Plast Surg 2008;60:283)
  • Laser surgery if inoperable (Clin Exp Dermatol 2007;32:159)
  • Clinical images
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    Newborn with giant hairy congenital nevus

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    Ulcerated nodule within scalp

    Microscopic (histologic) description
  • Similar to congenital nevus
  • Deeper nevus cells may be E-cadherin negative, contributing to their motility (J Dermatol Sci 2008;52:21)
  • Microscopic (histologic) images
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    Proliferation of melanocytes along hair follicle

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    Melanocytes are uniform in large ulcerated nodule

    Molecular / cytogenetics description
  • May have proteomic alterations that predispose to tumorigenesis (Proteome Sci 2012;10:50)