THERE is now general agreement1-3 that in about 50% of institutionalized epileptic patients who die of natural causes, an autopsy will disclose a lesion. This was first demonstrated macroscopically in 1825, in 9 out of 18 cases, by Bouchet and Cazauvieilh,1 who called it Ammon's horn sclerosis (synonyms—sclerosis of the cornu Ammonis and hippocampal sclerosis). Its histopathology was subsequently described in 1880 by Sommer.4 This lesion has also been called "incisural sclerosis"5 and "pararhinal sclerosis".6,7 Both these terms, however, have now acquired rather misleading connotations, one of difficult birth and the other of olfactory perception. We therefore prefer the simpler term "mesial temporal sclerosis" (MTS) because the sclerotic process usually involves other structures, such as the amygdala and uncus, as well as the hippocampus, and because the term which has since been adopted by others is purely descriptive without etiological or functional implications8 (Figure).
Falconer MA, Taylor DC. Surgical Treatment of Drug-Resistant Epilepsy Due to Mesial Temporal SclerosisEtiology and Significance. Arch Neurol. 1968;19(4):353–361. doi:10.1001/archneur.1968.00480040019001
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