Epilepsy in isolated parenchymal neurocutaneous melanosis: A systematic review

Neurocutaneous melanosis (NCM) is a rare congenital syndrome characterized by giant melanocytic cutaneous nevi and melanosis within the central nervous system (CNS), often sparing leptomeninges and concentrated in the brain parenchyma. Epilepsy and neurodevelopmental abnormalities are the only complications reported in children with isolated parenchymal melanosis. A minority of patients experience drug-resistant epilepsy, and up to now, no predictors of epilepsy prognosis have been identified.

In this systematic review, according to preferred reporting items for systematic review and meta-analysis (PRISMA) guidelines, we aggregated clinical cases of patients with isolated parenchymal melanosis affected by epilepsy, in order to recognize predictors of clinical outcome and to clarify indications of available therapeutic approaches.

Sixteen articles (19 patients) were included in the final analysis from initial database research; 4 articles (4 patients) were selected from reference lists and 1 from conference abstracts (1 patient). In our series, distribution of parenchymal melanosis was the best predictor of epilepsy outcome: frequencies of seizure-free patients were different between cases of isolated/bilateral amygdale melanosis and those of multiple localizations (p = 0.037). Failure of antiepileptic drugs (AEDs) and/or surgical epilepsy therapy were associated with poor cognitive outcome (p = 0.03).

Antiepileptic drugs were effective in the majority of patients with epilepsy with parenchymal melanosis. In case of multifocal distribution, more than one-third of patients presented a drug-resistant epilepsy. Epilepsy surgery is the best choice in patients with isolated amygdala localization. We propose the recognition of a multifactorial nature of cognitive impairment in neuromelanosis, emphasizing the role of drug-resistant epilepsy.