ABSTRACT
Objective To study a histopathological classification system for hippocampal cell loss in patients suffering from mesial temporal lobe epilepsy.Methods Fifty-one surgically resected specimens were microscopically examined with respect to neuronal cell loss in hippocampal subfields CA1—CA4.Clinical data including age at first seizure,with or without initial precipitating injuries (IPIs),latecy,epilepsy duration,Engel score of half and one year after surgery were collected to analyse the clinical characteristics between different pathological types.Eight additional hippocampal specimens obtained from neurologically healthy autopsies served as controls.Results (1)Five distinct patterns were recognized within a consecutive cohort of anatomically well-preserved surgical specimens.Type 1 a (21/51,41.18 ％):severe cell loss in CA1 and moderate neuronal loss in all other subfields excluding CA2; Type 1b(18/51,35.2％):severe cell loss in all sectors; Type 2(9/51,17.65％):severe neuronal loss restricted to sector CA1 ;Type 3 (1/51,1.96％):severe neuronal loss restricted to the hilar region; no mesial temporal sclerosis (2/51,3.92％):a group comprised hippocampi with neuronal cell densities not significantly different from age matched autopsy controls.(2)The patients of type 1 a and 1 b had younger age of first onset,longer latency and duration,more frequency of IPIs,the proportion of ourrence of febrile seizures in type 1a was 10/19,type 1b was 7/16,type 2 was 4/7,type 3 was 0 (x2 =11.790,P =0.019).(3) The patients of type 1a and 1 b had better postsurgical outcome.Conclusion Type 1 is the most common type of mesial temporal sclerosis,which have better postsurgical outcome than the other 3 types.