Linear epidermal nevus and nevus sebaceus syndromes: a clinicopathologic study of 3 patients

Linear epidermal nevus syndrome and linear sebaceus nevus syndrome are rare neurocutaneous syndromes characterized by epidermal nevi, epilepsy, and mental retardation. Pathologic descriptions of the central nervous system findings in such patients are rare.

We examined the clinicopathologic features of 2 patients with linear epidermal nevus syndrome and 1 with nevus sebaceus syndrome who underwent surgical resections for chronic epilepsy in a tertiary referral center with a high volume of epilepsy surgery.

Patients included 3 females, aged 11 months (patient 1), 8 years (patient 2), and 2 1/2 years (patient 3) at the time of surgery. The duration of seizures prior to surgery was 11 months, 6 years, and 28 months, respectively. Two patients had epidermal nevi involving the head region (patients 1 and 3), and 1 had a nevus sebaceus of Jadassohn (patient 2); patient 2 had a choristoma, and patient 3 had a dermoid cyst in the eye region. Patient 1 demonstrated hemimegalencephaly radiographically. Histologic examination of resected cortical tissue in patients 1 and 2 demonstrated severe diffuse cortical dysplasia characterized by a disorganized cortical architectural pattern, a haphazard orientation of cortical neurons, and increased molecular layer neurons. Gyral fusion was seen in patient 1. Pial glioneuronal hamartomas were observed in patient 1. Prominent cortical astrocytosis was seen in patients 1 and 2, and foci of microcalcification were evident in patient 1. Cortical dysplasia was milder in patient 3 and consisted of an increased number of molecular layer neurons. Neuronal heterotopia was observed in all 3 patients.

The spectrum of neuronal migration abnormalities in the setting of these syndromes may be variable in terms of its histologic phenotypic manifestations.