Temporal lobe epilepsy and corpora amylacea in the hippocampus: clinicopathologic correlation

Corpora amylacea (CoA) have been found in about 60% of neurosurgical specimens showing hippocampal sclerosis (HS). To determine clinical and neuroimaging differences between HS with and without CoA, we studied 29 patients (21 male, 8 female; age at surgery, 12 to 49 years) who underwent anterior temporal lobectomy for intractable medial temporal lobe epilepsy. No CoA were noted in the hippocampus of 11 cases, and deposition of CoA was mild and limited to the subependymal and vestigial hippocampal sulcus regions in nine cases; in nine cases, moderate to marked deposition was noted in the pyramidal cell layer, accompanying severe neuronal loss. No significant differences were evident between these three groups for age at onset, frequency and duration of epileptic seizures, the average age at surgery, or surgical results. Hippocampal hyperintensity in fluid-attenuated inversion recovery magnetic resonance images tended to increase with increasing hippocampal deposition of CoA. Formation of CoA appears to be a response to neuronal loss in the pyramidal cell layer, being related to the epileptogenic process as a consequence rather than a cause.