Epidermal nevi of the face and neck seem to be
associated with a higher rate of cerebral anomalies when compared to
epidermal nevi limited to the trunk. Seizures (that may be difficult to
treat) and mental retardation (mild to very severe) complicate the
neurologic abnormalities and occur in approximately two thirds of patients.
Seizures typically start by the end of the first year of life and may
include apneic, myoclonic, psychomotor, Jacksonian, and grand mal types of
seizures. Cranial nerve disorders usually involve palsy of the sixth, seven,
and eighth cranial nerve. Occasional cortical atrophy, hydrocephalus,
cerebral hemangiomas or vascular malformations, hemimegalencephaly
(typically ipsilateral to the skin lesions), agenesis of the corpus callosum
and/or the cerebellar vermis, cysts continuous with the fourth ventricle of
the brain, porencephaly, macrocephaly, hypotonia, hyperkinesia, hemiparesis
or hemiplegia, cerebral calcifications, and cerebral tumors may be
associated. Dandy-Walker Malformation (absence of the cerebellar vermis,
hydrocephalus, and posterior fossa cyst continuing with the fourth
ventricle) occurs in some cases. Neurogenic tumors may occur along the
spinal cord. The skin shows epidermal nevi associated with nevus flammeus,
sebaceous hypertrophy, hypopigmentation, café au lait spots, acanthosis
nigricans, and mixed verrucous lesions. Blindness (retinal changes similar to those in
Coats Disease have been reported) is not an uncommon finding, and
additional ocular features may include colobomas of the eyelid, iris, and
retina, subconjunctival lipodermoids, corneal clouding and vascularization,
ptosis, ectopic displacement of the pupils, exotropia/esotropia tear duct
stenosis, macrophthalmia/microphthalmia, and nystagmus.