Large or multiple congenital melanocytic nevi: occurrence of neurocutaneous melanocytosis in 1008 persons.

BACKGROUND: There is a dearth of information regarding the occurrence of neurocutaneous melanocytosis (NCM) in a large cohort of persons with large congenital melanocytic nevi (LMCN) or multiple congenital melanocytic nevi (MCMN).
OBJECTIVE: The purpose of this article is to report occurrence of NCM and other complications in 1008 persons having LCMN or MCMN.
METHODS: Evaluation of information obtained from a database of persons with LCMN or MCMN voluntarily submitted by the affected persons to a nevus support group, the Nevus Network.
RESULTS: Of those with truncal LCMN, 6.8% developed significant complications, 4.8% developed symptomatic NCM, and 2.3% died from either benign or malignant NCM or cutaneous melanoma. Of the 4.8% of persons with a truncal nevus who developed symptomatic NCM, 34% died. Of those with head or extremity LCMN, 0.8% developed symptomatic NCM, and, to date, none have died from any cause. Of the small number with MCMN without a giant nevus, 71% developed symptomatic NCM, and 41% died of it. LIMITATIONS: Attending physician confirmation of submitted information was unavailable.
CONCLUSIONS: LCMN of the trunk were associated with a relatively low occurrence of medical complications and death in our group, considering the large nevomelanocytic burden present. If symptomatic NCM developed in those with truncal nevi, the occurrence of death rose to a third. LCMN of the head or extremity were associated with minimal medical complications and no deaths. In contrast, most of the rare persons (N = 17) with MCMN developed symptomatic NCM, and more than a third died.