Neurocutaneous melanosis associated with Dandy-Walker malformation and a meningohydroencephalocele. Case report.

Neurocutaneous melanosis and Dandy-Walker malformation are both forms of rare congenital neurodysplasia. Interestingly, 8 to 10% of patients with neurocutaneous melanosis also harbor an associated Dandy-Walker malformation, indicating that these developmental abnormalities share a common origin. The authors describe a case of neurocutaneous melanosis associated with Dandy-Walker malformation and an occipital meningohydroencephalocele with a giant melanotic nevus. Multiple congenital liver masses were also observed in the infant. The occipital nevus was totally excised, and ventriculoperitoneal and cyst-peritoneal shunts were created to prevent subsequent hydrocephalus. Findings in this case support the possibility that excessive melanocytes hinder normal mesenchymal development, causing Dandy-Walker malformation and an occipital meningocele.