congenital melanocytic nevus

^[1]^[2]

Introduction

present at birth
some lesions may become visible after birth "fading in" as a large lesion over a period of weeks (tardive)
equal prevalence in males & females
all races
1% of white newborns - most < 3 cm in diameter

present at birth
isolated lesions, may be found on any skin surface
variably sized, may cover entire body parts
medium-dark brown, variegated color across lesion
generally round or oval with regular or irregular borders
generally a plaque with rough or lobulated surface, increasingly so with time
coarse hair growth
may involve leptomeninges if large lesion occurs on head
- seizures
- focal neurologic deficits
- obstructive hydrocephalus

large or giant congenital melanocytic nevus
- risk of melanoma is 6.3%
- diagnosis generally made between 3-5 years of age
- prognosis is poor
small lesions - lifetime risk of melanoma is 1-5%

small nevi not known to be present at birth should be assumed to be acquired & managed according to appearance
atypical appearing lesions should be surgically excised
small congenital melanocytic nevi should be removed before age 12
large nevi > 1.5 cm
- periodic follow-up for life
- prophylactic surgical excision
  - excision with full-thickness skin graft as indicated
  - swing flaps, tissue expanders for large lesions
giant lesions
- risk of developing melanoma is significant before age 3-5
- lesion should be excised as soon as possible
- techiniques using patients own skin grown in tissue culture
- tissue expanders

↑ Saunders Manual of Medical Practice, Rakel (ed), WB Saunders, Philadelphia, 1996, pg 960-61
↑ Color Atlas and Synopsis of Clinical Dermatology, Common and Serious Diseases, 3rd ed, Fitzpatrick et al, McGraw Hill, NY, 1997, pg 187-91