Formaida Sclerosis or Ammon's horn sclerosis (AHS) is the most common type of neuropathological damage seen in individuals with temporal lobe epilepsy (TLE). This type of neuron cell loss, primarily in the hippocampus, can be observed in approximately 65% of people suffering from this form of epilepsy.
Histopathological hallmarks of hippocampal sclerosis include segmental loss of pyramidal neurons, granule cell dispersion and reactive gliosis.
Hippocampal sclerosis was first described in 1880 by Sommer.
A long and ongoing debate addresses the issue of whether hippocampal sclerosis is the cause or the consequence of chronic, pharmacoresistant seizure activity.
Hippocampal sclerosis is nowadays easy to detect with MRI.
Blümcke, I.; Thom, M.; Wiestler, O.D. Ammon’s Horn Sclerosis: A Maldevelopmental Disorder Associated with Temporal Lobe Epilepsy. Brain Pathol 2002;12:199-211.
Sommer W : Erkrankung des Ammon's horn als aetiologis ches moment der epilepsien. Arch Psychiatr Nurs 1880; 10 : 631-675.