Dados do Trabalho

Título

Hippocampal sclerosis with dysmorphic neurons in temporal lobe epilepsy

Apresentação do caso

A right-handed 18 years-old man, born by cesarean delivery due to acute fetal distress but without delay in neuropsychomotor development, was evaluated for surgical treatment of pharmacoresistant epilepsy. At age eight, he presented two tonic-clonic seizures, one lasting 30 minutes. Seizures recurred at age 13, with weekly to daily episodes of fear and tachycardia sometimes evolving with behavioral arrest, masticatory and left manual automatisms, left-side oculocephalic deviation, and bladder release. At age 16, he developed depression, social withdrawal, aggressiveness, self-mutilation, and suicidal ideation/attempts. Seizures were resistant to oxcarbazepine, valproate, phenobarbital, phenytoin, carbamazepine, levetiracetam, lamotrigine, and clobazam. Brain MRI showed increased hippocampal volume, T2/FLAIR hyperintensity, and loss of internal architecture, suggesting a long-term epilepsy-associated tumor (LEAT). Video-EEG monitoring revealed organized background activity, with occasional left anterior temporal focal epileptiform paroxysms and impaired awareness seizures with onset at the same topology. The neuropsychological test showed an IQ of 109 and mild deficits in immediate memory, fluency, and verbal memory, suggesting dominant hemisphere temporal lobe involvement. He underwent left amygdalohippocampectomy and remained with aware focal seizures, which improved after ASM adjustment (Engel Ib). The histopathological revealed dimorphic neurons in the CA4 region, besides astrogliosis, a 2.5 fold increase in the capillary network area, and reduction in neuron density of CA4 and CA1, compatible with a combined hippocampal dysplasia type IIa + hippocampal sclerosis type 1.

Discussão

Focal cortical dysplasia type II (FCDII) is a common cortical malformation associated with early-onset frontal lobe epilepsy, while hippocampal sclerosis is the most frequent etiology of adult-onset temporal lobe epilepsy. While both are common pathologies, hippocampal dysplasia is a rare finding, only described by a few researchers. Although we saw reduced neuron density, the increased hippocampal volume might be related to the combination of increased capillary network, presence of larger dysmorphic neurons, and tissue astrogliosis.

Comentários finais

Hippocampal dysplasia is a rare finding, but should be considered when histopathological evaluation comes negative for LEAT in a case with an increased MRI hippocampal volume.