Neuropathological findings in patients with mesiotemporal
epilepsy: Frequent occurrence of dual pathology
Kršek P.1, Zámečník J.2, Druga R.3, Marusič P.4,5, Komárek V.1, Beneš V., Jr.5,Tichý M.6, Zárubová J.7, Hadač J.8, Hovorka J.9
1Klinika dětské neurologie UK 2. LF a FN Motol, Praha, 2Ústav patologie a molekulární medicíny UK 2. LF a FN Motol, Praha, 3Pracoviště funkční anatomie UK 2. LF, Praha, 4Neurologická klinika UK 2. LF Motol, Praha, 5Neurochirurgická klinika UK 1. LF, ÚVN a IPVZ, Praha, 6Neurochirurgické oddělení FN Motol, Praha, 7Neurologická klinika FTN a IPVZ, Praha, 8Klinika dětské neurologie FTN a IPVZ, Praha, 9Neurologické oddělení a Neuropsychiatrické centrum, Nemocnice Na Františku, Praha |
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Summary:
Background: The most frequent type of pharmacoresistant epilepsy indicated for surgical therapy is
mesiotemporal epilepsy (MTLE). Typical structural basis of MTLE is mesiotemporal sclerosis (MTS);
however, it becomes evident that diverse histopathology and etiopathogenesis make patients with MTS
a heterogeneous group. In some of them, dual pathology, i.e., focal lesion of temporal neocortex is found
in combination with MTS. Methods:We have histologically analysed resected brain tissue of 15 patients
(age 17–38 years) with the diagnosis of MTLE who were indicated for anteromesial temporal resection;
their neuropathological findings were correlated with data from clinical history and the results of
preoperative examinations. Standard preoperative investigation protocol included electrophysiology
(EEG, video EEG), imaging (MRI), functional (SPECT, PET, MRS) and neuropsychological exams. Both
mesial archicortical structures and temporal pole neocortex were analysed with conventional histological
techniques. Results: In all cases, histology confirmed the clinical suspicion of MTS; in addition,
dual pathology was detected in 9 out of 15 patients. These were predominantly congenital malformations
of cortical development (in 7 cases). Only in one case was the dual pathology uncovered with preoperative examinations. The initial insult that is probably connected to the development of MTS
(complicated febrile seizures, craniocerebral trauma, meningoencephalitis) has been found in clinical
history in 12 patients (80 %). In all three patients without predisposing clinical history, there was an
congenital abnormality of neocortex. Discussion: We believe that in some patients lacking the initial
insult, MTS arises specifically as a result of congenital cortical changes. From the presented data it is
evident that neuropathological examination not only significantly contributes to understanding of the
etiopathogenesis of pharmacoresistant epilepsy but also it can influence the therapeutical approach
in epileptosurgical patients.
Key words:
epilepsy surgery, mesiotemporal epilepsy, hippocampal sclerosis, dual pathology, cortical
dysplasia
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