An 8-year-old boy is being evaluated due to drug-resistant epilepsy. The patient has had recurrent seizures since age 2, which have remained uncontrolled despite multiple antiepileptic medications. He has no history of head trauma, meningitis, or encephalitis. There is no family history of seizure disorder. Electroencephalography reveals epileptic foci originating from the left temporal lobe, and neuroimaging reveals an abnormality of the left hippocampus. Surgical resection of the cortical region from which the seizure originates is performed. Histopathological examination of the removed brain tissue is most likely to reveal which of the following findings?

Question

An 8-year-old boy is being evaluated due to drug-resistant epilepsy.  The patient has had recurrent seizures since age 2, which have remained uncontrolled despite multiple antiepileptic medications.  He has no history of head trauma, meningitis, or encephalitis.  There is no family history of seizure disorder.  Electroencephalography reveals epileptic foci originating from the left temporal lobe, and neuroimaging reveals an abnormality of the left hippocampus.  Surgical resection of the cortical region from which the seizure originates is performed.  Histopathological examination of the removed brain tissue is most likely to reveal which of the following findings?

Quizplus · Accepted Answer

11ec160b_39db_7df4_9249_37e87dc33061_MD0001_00 This patient with recurrent seizures has an epileptogenic focus in the temporal lobe, suggesting temporal lobe epilepsy (TLE), the most common type of localization-related (ie, focal) epilepsy. Localization epilepsies occur when partial seizures originate from one area of the brain and are usually due to an underlying structural disorder which serves as an epileptogenic focus. In the case of TLE, this is most commonly due to hippocampal sclerosis, which is usually visible as hippocampal atrophy on MRI. The pathogenesis of hippocampal sclerosis is incompletely understood but may in some cases be related to prior prolonged febrile seizures, particularly in patients with an underlying genetic predisposition. This results in the characteristic histopathologic findings of atrophy of the hippocampal neurons with marked reactive gliosis (astrocyte proliferation in response to injury). Surgical resection may reduce or cure seizures associated with TLE. (Choice B) Hemosiderin-laden macrophages are associated with prior intracerebral hemorrhage, which may cause seizures but typically presents acutely with altered mental status and focal neurologic deficits. Neuroimaging would demonstrate expanding blood, not a focal abnormality in the hippocampus. (Choice C) Microglial nodules form when cells of microglia surround a neuron and phagocytize it. The nodules are most commonly seen in viral CNS infection (particularly HIV) and are not typically associated with TLE. (Choice D) Neuronal inclusion bodies are often seen in frontotemporal dementia (characterized by prominent personality/behavioral changes and atrophy of the frontal and temporal lobes on neuroimaging) and Parkinson disease (characterized by bradykinesia, rigidity, pill-rolling tremor, and dementia). These disorders occur in elderly patients and are not associated with seizures. (Choice E) Spongiform changes occur in prion diseases (eg, Creutzfeldt-Jacob, kuru). Patients have progressive tremors, ataxia, and dementia. Electroencephalography reveals periodic sharp-wave complexes, not focal epileptiform discharges, and hippocampal abnormalities are unexpected. Educational objective: Temporal lobe epilepsy is most commonly due to hippocampal sclerosis. Histopathology of hippocampal sclerosis demonstrates atrophy of the hippocampal neurons with marked reactive gliosis (astrocyte proliferation in response to injury).

An 8-Year-Old Boy Is Being Evaluated Due to Drug-Resistant Epilepsy