Abstracts

Epidermal nevus syndrome (ENS) is an uncommon neurocutaneous disorder, in which epidermal nevi are associated with congenital malformations of other organs, especially of the central nervous system, eye and skeleton. Cardiac, genitourinary and other developmental defects may also be seen. Approximately 450 clinically diverse cases of ENS have been reported (as estimated by the National Organization for Rare Disorders).
In 1991 Pavone et al. identified a small subgroup of ENS patients with a recognizable neurologic syndrome consisting of facial epidermal nevus, ipsilateral hemimegalencephaly (HME), mental retardation, seizures and often ipsilateral facial hemihypertrophy.
Scattered reports of similar cases are found in the literature. This study examines 7 additional cases of ENS/HME presenting with epilepsy during infancy or early childhood.
A total of 1826 consecutive patients (pts), who were admitted to the pediatric epilepsy monitoring unit between 1994-2002, were reviewed. All pts underwent continuous video-EEG monitoring and neuroimaging for evaluation of seizures.
Seven pts (7/1826, 0.38%) with epilepsy and a linear epidermal nevus involving the face were identified. All 7 had radiographic (MRI) evidence of ipsilateral HME associated with extensive cerebral malformation.
Median age of seizure onset was 1 week after birth (range: 3 hours to 4 years). Semiology included infantile spasms 4 pts, hypomotor seizures 3, myoclonic 3, and generalized tonic seizures 4 pts. Bilateral clonic activity was seen in 2 and unilateral clonic seizures in another 2 pts. Interictal EEG consisted of unilateral hypsarrhyrhythmic patterns in 3 pts and generalized hypsarrythmia in 1. The remainder (3 pts) had multiregional sharp waves lateralized to the abnormal side; in addition generalized interictal discharges were seen in 1 case. Ictal EEG patterns were: lateralized to the HME side 4 pts, generalized 1, multiregional arising independently from both hemispheres 1 and regional parieto-occipital in another patient.
All pts had pharmaco-resistant seizures, mild to severe developmental delay and hemiparesis. Epilepsy surgery was offered to 6/7 pts. Two families elected to continue medical therapy. Four opted for resective surgery (3 hemispherectomies and 1 extensive temporal lobectomy). Median age at the time of surgery was 15 months (range 7-34 months). Two hemispherectomy (HSE) pts were seizure-free nearly 2 years after surgery. The other 2 had recurrence of seizures within 3 months of surgery. One underwent repeat anatomic HSE and is now seizure-free ([gt]1 year follow up), while the second patient continues to have recurrent seizures.
ENS is a rare disorder, which may be associated with HME and epilepsy. Although the underlying pathophysiologic mechanisms are not well understood, increased familiarity with the ENS/HME variant will facilitate early recognition and evaluation of patients. Epilepsy surgery may lead to seizure freedom in selected cases.