<unk>  is associated with the presence of either giant congenital melanocytic nevi or non-giant nevi of the skin. It is estimated that<unk>  is present in 2% to 45% of patients with giant congenital melanocytic nevi. Patients with non-giant congenital melanocytic nevi seem to have a much lower, but undefined risk. Of these patients, only a small number are symptomatic, usually displaying symptoms before the age of 2. These symptoms are the result of melanocytic lesions being present in the leptomeninges of the central nervous system. Symptoms can include: * Papilledema * Cranial palsies * Headache * Vomiting * Seizures Others symptoms may also exist that are related to an increase in intracranial pressure. These symptoms seem to be present regardless of the malignancy of the melanin deposits within the central nervous system. Approximately 10% of patient with<unk>  also present the Dandy–Walker syndrome and associated Dandy-Walker malformation. This malformation involves an enlargement of the posterior fossae and fourth ventricle along with agenesis of the cerebellar vermis. The abnormalities of the leptomeninges during fetal development due to<unk>  may be the cause of this increased incidence of the Dandy-Walker malformation. The development of hydrocephalus is the most common symptom associated with a combination of<unk>  and a Dandy-Walker malformation, occurring in about two out of three patients.
Neurocutaneous melanosis
Nevus anemicus
Phakomatosis pigmentokeratotica
Granulomatous slack skin
Blue nevus
Erythema dyschromicum perstans
Sparganosis
Hypertrichosis cubiti