Abstracts

Objective: To study the incidence and clinical characteristics of children with mesial temporal sclerosis (MTS) as diagnosed by magnetic resonance imaging (MRI).
MTS has not been well studied in children. In children, it is believed to be an uncommon finding and not a major cause of epilepsy. No studies have been performed specifically on the MRI diagnosis and incidence of MTS in children. We reviewed all pediatric brain MRI reports and studied the incidence and clinical features of those with MTS in detail.
METHODS: All brain MRI reports on children under 14 years of age over a 52-month period (Jan 1997 to April 2002) were reviewed. All reports with the diagnosis of definite or possible MTS were noted. These patients[ssquote] MRI scans were then reviewed by two board-qualified pediatric neurologists to confirm the MRI diagnostic criteria of MTS. The charts of the patients who satisfied these criteria were then reviewed in detail to study their clinical details.
RESULTS: 390 brain MRI reports were reviewed. 14 reports of MTS were found. 12 of the 14 MRI films satisfied the criteria of MTS by MRI after the films were reviewed. The incidence of MTS amongst all pediatric brain MRI studies was 3.1%. The 12 children consisted of six males. The average age was 6.4 years (range 2-12 years) at time of initial MRI diagnosis of MTS. Six patients had left MTS, five had right MTS and one patient had bilateral MTS. 11 of the 12 patients had been imaged utilizing a specific epilepsy protocol. Five patients had other MRI pathology, including dysgenesis of the corpus callosum, periventricular leukomalacia (PVL) and gliosis. All 12 children presented with seizures i.e. there were no [dsquote]incidental[dsquote] findings of MTS. The patients[ssquote] seizure types consisted of complex partial (n = 9), typical absence (n = 1), generalized tonic-clonic (n = 1) and both complex partial and generalized tonic-clonic (n = 1). Only one patient had a history of febrile seizures. At the latest follow-up, histopathology results were available on 6 patients, all of whom had undergone temporal lobectomy as a treatment for refractory, complex partial seizures. This showed MTS and surrounding gliosis and/or dysplasia in four patients, isolated MTS in another and gliosis in the sixth. Only one patient had a likely cause of his MTS (bilateral) due to encephalitis 3 years prior to MRI diagnosis of MTS. Of the nine available perinatal histories, seven were normal and two were abnormal only for prematurity and threatened abortion (patient with (PVL)). Associated comorbidities were seen in five patients and included developmental delay, behavioral problems, cerebral palsy and Gorlin syndrome.
CONCLUSIONS: MTS is an uncommon finding in children. Asymptomatic MTS or MTS not presenting as seizures did not occur in our series. Febrile seizures occurred in only one of the 12 children, so unlike MTS in adults, this may be a very low association. Histopathology in six children confirmed MTS in five and there was associated gliosis and/or dysplasia in four. In children, MTS often occurs in the setting of dual pathology, has associated comorbidities and seizure types other than complex partial.