Giant congenital nevus

Skin melanocytic tumor

Topics to be merged

Author: Christopher S. Hale, M.D.

Topic Completed: 1 November 2012

Minor changes: 3 April 2019

Copyright: 2003-2019, PathologyOutlines.com, Inc.

PubMed Search: Giant congenital nevus

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Table of Contents

Cite this page: Hale C Giant congenital nevus. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/skintumormelanocyticgiantcongenitalnevus.html. Accessed August 11th, 2020.

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

Images hosted on other servers:

Newborn with giant hairy congenital nevus

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

Images hosted on other servers:

Proliferation of melanocytes along hair follicle

Melanocytes are uniform in large ulcerated nodule

Molecular / cytogenetics description

May have proteomic alterations that predispose to tumorigenesis (Proteome Sci 2012;10:50)