Photograph courtesy of John R Stevenson, MD
The giant congenital nevus (GCN) is defined as a congenital nevus > 20 cm in greatest diameter in the adult. The lifetime risk of developing a melanoma in a giant nevus has been estimated to be about 5-6%. To put this in perspective, the lifetime risk of breast cancer for women is about 10%. Even after being previously excised, melanoma can rarely develop, e.g., 34 years after the final stage of excision [JAMA Derm 2014;150;100].
A large, pigmented plaque at birth is seen. Usually, the back and sacrum--the bathing trunk area--are involved. Smaller, "satellite" lesions may be scattered on the body separate from the larger nevus.
Vitiligo may be associated with a GCN. Depigmented patches may occur within, adjacent to, or distal from the nevus [PD 2016;33;307]. One patient was reported with halo depigmentation around some satellite nevi.
Martins da Silva et al studied the distribution of giant congenital nevi and came up with 6 repeatable patterns [JAAD 2017;76;689].
For larger lesions, involvement of a plastic surgeon is recommended. Staged excisions and tissue expanders are often employed in removing large lesions. Curettage early in life has been advocated for large congenital nevi [AD 2002;138;943].
Photograph courtesy of Theodore Sebastian, MD
Very nice report showing spontaneous regression. Photos are from birth and age 14. Indian J Dermatol Venereol Leprol 2014;80:243-6
Innumerable nevi may accompany a giant congenital nevus. JAAD Case Reports September 2015 Volume 1, Issue 5, Pages 241–243
Large congenital nevi have been reported to spare the nipple, so called "nipple-sparing nevus of the breast.” Pediatric Dermatology Vol. 32 No. 4 514–517, 2015
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