title: Seizure outcome in surgically treated drug-resistant mesial temporal lobe epilepsy based on the recent histopathological classifications.
abstract: OBJECTIVE
  The study was performed to investigate the relation between seizure outcome after surgical treatment of mesial temporal lobe epilepsy (MTLE) and pathological findings, classified according to the recently proposed classifications of mesial temporal sclerosis (MTS), granule cell pathology (GCP), focal cortical dysplasia (FCD) and epilepsy-associated low-grade tumors (ELGT).
  
  
  METHODS
  The authors analyzed data obtained in 120 consecutive cases involving patients presenting with drug-resistant MTLE, who underwent tailored anteromesial temporal lobe resection, and correlated seizure outcome with pathological findings. They identified 5 histopathological groups: Group 1-ELGT, alone or associated with other lesions (30 cases); Group 2-isolated FCD (17 cases); Group 3-MTS, with or without GCP (28 cases); Group 4-MTS associated with FCD, with or without GCP (37 cases); Group 5-other lesions (8 cases).
  
  
  RESULTS
  Engel Class I outcome was observed in 83% of patients with ELGT (Class IA in 63%); in 59% of patients with isolated FCD, with FCD Type II showing a better prognosis than FCD Type I; in 82% of patients with isolated MTS (Class IA in 50%), with MTS Type 1a and MTS Type 1b showing a better prognosis than MTS Type 2 and patients with MTS and GCP having better postsurgical results than those with MTS without GCP. Engel Class I outcome was also achieved in 84% of patients with FCD associated with MTS (Engel Class IA in 62%); also in this group MTS 1a and MTS 1b associated with FCD showed a better prognosis than FCD associated with MTS 2. Finally, Engel Class I was also achieved in 2 patients with vascular malformation and in 1 with a temporal pole encephalocele.
  
  
  CONCLUSIONS
  Patients with MTLE and ELGT, MTS, or MTS associated with FCD showed the best postsurgical seizure outcome (Engel Class I in more than 80% of cases), whereas only 63% of patients with isolated FCD achieved the same type of outcome. Interestingly, the analysis of seizure outcome in histopathological subtypes of FCD and of MTS showed different prognoses in the different pathological subgroups, with worse outcomes for atypical MTS, absence of GCP, and isolated FCD Type I.
authors: Division of Neurosurgery, IRCCS Institute of Neurological Sciences, Bellaria Hospital, Bologna, Italy. giulioni.m@tiscali.it
authors: Marco
authors: M
authors: Giulioni
authors: Gianluca
authors: G
authors: Marucci
authors: Matteo
authors: M
authors: Martinoni
authors: Lilia
authors: L
authors: Volpi
authors: Patrizia
authors: P
authors: Riguzzi
authors: Anna Federica
authors: AF
authors: Marliani
authors: Francesca
authors: F
authors: Bisulli
authors: Paolo
authors: P
authors: Tinuper
authors: Carlo Alberto
authors: CA
authors: Tassinari
authors: Roberto
authors: R
authors: Michelucci
authors: Guido
authors: G
authors: Rubboli
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001927:Brain Diseases / Q000150:complications / Q000473:pathology / Q000601:surgery*; D001932:Brain Neoplasms / Q000150:complications / Q000473:pathology / Q000601:surgery; D002648:Child; D002675:Child, Preschool; D004351:Drug Resistance; D004828:Epilepsies, Partial / Q000145:classification* / Q000209:etiology / Q000473:pathology / Q000601:surgery*; D004833:Epilepsy, Temporal Lobe / Q000145:classification* / Q000209:etiology / Q000473:pathology / Q000601:surgery*; D005260:Female; D006801:Humans; D008297:Male; D054220:Malformations of Cortical Development / Q000150:complications / Q000473:pathology / Q000601:surgery; D008875:Middle Aged; D011183:Postoperative Complications; D012042:Registries; D012598:Sclerosis / Q000150:complications / Q000473:pathology / Q000601:surgery; D016896:Treatment Outcome; D055815:Young Adult