Asymptomatic neurocutaneous melanocytosis in patients with large congenital melanocytic nevi: a study of cases from an Internet-based registry.

Overview

BACKGROUND: Recent retrospective studies using magnetic resonance imaging (MRI) to screen for neurocutaneous melanocytosis (NCM) among neurologically asymptomatic children with large congenital melanocytic nevi (LCMN) report high prevalence (23-30%) of asymptomatic NCM. We sought to determine prevalence of asymptomatic NCM, and current application of MRI as a screening tool. METHODS: Patients with LCMN from an Internet-based registry answered a questionnaire regarding NCM status. RESULTS: Of 379 patients with LCMN, 26 reportedly had NCM, with 17 reporting neurologic symptoms. Of 186 patients undergoing MRI, 9 reported abnormal findings without neurologic symptoms (4.8%); 80% had LCMN on the posterior axis, whereas 55% had more than 20 satellite nevi. LIMITATIONS: Study data rely on the registry members' self-reported findings and are limited by lack of independent data verification. CONCLUSION: Asymptomatic NCM (determined by MRI) may not be common, with much lower prevalence (4.8%) than previously reported. MRI is widely used for screening patients at risk for NCM, such as patients with LCMN involving the posterior axis and greater than 20 satellite nevi.