Sturge-Weber Syndrome Is Associated with Cortical Dysplasia ILAE Type IIIc and Excessive Hypertrophic Pyramidal Neurons in Brain Resections for Intractable Epilepsy.

Sturge-Weber syndrome (SWS) is a rare syndrome characterized by capillary-venous malformations involving skin and brain. Many patients with SWS also suffer from drug-resistant epilepsy. We retrospectively studied a series of six SWS patients with epilepsy and extensive neurosurgical resections. At time of surgery, the patients' age ranged from 11 to 35 years (with a mean of 20.2 years). All surgical specimens were well preserved, which allowed a systematic microscopical inspection utilizing the 2011 ILAE classification for focal cortical dysplasia (FCD). Neuropathology revealed dysmorphic-like neurons with hypertrophic cell bodies reminiscent to those described for FCD type IIa in all cases. However, gross architectural abnormalities of neocortical layering typical for FCD type IIa were missing, and we propose to classify this pattern as FCD ILAE type IIIc. In addition, our patients with earliest seizure onset also showed polymicrogyria (PMG; n = 4). The ictal onset zones were identified in all patients by subdural electrodes, and these areas always showed histopathological evidence for FCD type IIIc. Four out of five patients had favorable seizure control after surgery with a mean follow-up period of 1.7 years. We concluded from our study that FCD type IIIc and PMG are frequently associated findings in SWS. FCD type IIIc may play a major epileptogenic role in SWS and complete resection of the associated FCD should be considered a prognostic key factor to achieve seizure control.

Clinicopathological associations in temporal lobe epilepsy patients utilising the current ILAE focal cortical dysplasia classification.

OBJECTIVES: This study utilised the revised 2011 ILAE classification of focal cortical dysplasia (FCD) (Blümcke et al., 2011) to examine pathology in a cohort of children and adults who underwent temporal lobe epilepsy (TLE) surgery, and to describe the electroclinical and imaging features associated with these pathologies. METHODS: The sample population were children (n=26) and adults (n=47) who underwent TLE surgery between 2002 and 2011 at our institutions. Neuropathology and MRI studies were re-reviewed by experts blinded to the original diagnosis. EEG and clinical data including current seizure outcome were determined by patient file review and/or patient contact. Pre-operative data, post-operative outcome and pathological diagnoses were compared. RESULTS: The commonest pathology in the adult cohort was isolated hippocampal sclerosis (HS) (n=24, 51.1%) and in the paediatric cohort, isolated tumour (n=10, 38.5%). Overall, HS with associated FCD (FCD IIIA) was the third most common pathology (n=12, 16.4%). Temporal grey matter signal changes on MRI were associated with FCD IIIA (p=0.035). FCD IIIA had the poorest post-surgical seizure outcome compared to all other pathologies (p=0.026). A history of bilateral convulsive seizures was more common in adults (n=40, p<0.0005), and was associated with failure to achieve postoperative seizure freedom (p=0.045). Postoperatively, paediatric TLE had higher rates of seizure freedom (p=0.005) and more children had ceased medication (p<0.0005). SIGNIFICANCE: FCD IIIA is a comparatively common pathological subtype in TLE, with a poor post-surgical outcome. Pre-operative recognition of FCD IIIA may be feasible through grey matter signal change on MRI. Paediatric patients had a higher rate of seizure freedom than adults. Pre-operative bilateral convulsive seizures were associated with poor outcome after surgery.