title: Dysembryoplastic neuroepithelial tumors: an MRI-based scheme for epilepsy surgery.
abstract: OBJECTIVE
  To determine optimal resections in the 3 dysembryoplastic neuroepithelial tumor (DNT) histologic subtypes (simple, complex, and nonspecific) based on MRI features.
  
  
  METHODS
  In 78 consecutive epilepsy patients operated for DNT, MRI features were classified as follows: type 1 (cystic/polycystic-like, well-delineated, strongly hypointense T1), type 2 (nodular-like, heterogeneous), or type 3 (dysplastic-like, iso/hyposignal T1, poor delineation, gray-white matter blurring). Correlations between histology, neurophysiologic findings, and surgical outcome were established for each MRI subtype.
  
  
  RESULTS
  Type 1 MRI (25 cases, in temporal and extratemporal areas) always corresponded to simple or complex DNTs. Type 2 MRI (25 cases, predominantly in neocortical areas) and type 3 MRI (28 cases, mainly in the mesial temporal lobe) corresponded to nonspecific forms. The epileptogenic zone (EZ) differed significantly according to the MRI subtype (p = 0.0029). It colocalized with the tumor in type 1 MRI, included perilesional cortex in type 2 MRI, and involved extensive areas in type 3 MRI. Cortical dysplasia was predominantly found in type 3 MRI (p < 0.0001). The main prognostic factors for seizure-free outcome (83%) were complete tumor (p < 0.0001) and EZ (p = 0.0115) removal. Other factors favorably influencing the outcome were a short epilepsy duration (p = 0.013) and absence of cortical-subcortical damage at the resection site (p = 0.053). Age at surgery was not related to outcome; however, cortical-subcortical damage was correlated with old age (p = 0.021). Treatment discontinuation was correlated with young age at surgery (p = 0.004) and short epilepsy duration (p = 0.001).
  
  
  CONCLUSIONS
  We propose that resection might be restricted to the tumor in type 1 MRI and be more extensive in other MRI subtypes, especially in type 3 MRI. Early surgery and clean surgical margins are crucial for curing epilepsy.
authors.affiliation: Departments of Neurosurgery, Centre Hospitalier Sainte-Anne, France. f.chassoux@ch-sainte-anne.fr
authors.forename: Francine
authors.initials: F
authors.lastname: Chassoux
authors.forename: Sebastian
authors.initials: S
authors.lastname: Rodrigo
authors.forename: Charles
authors.initials: C
authors.lastname: Mellerio
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Landré
authors.forename: Catherine
authors.initials: C
authors.lastname: Miquel
authors.forename: Baris
authors.initials: B
authors.lastname: Turak
authors.forename: Jacques
authors.initials: J
authors.lastname: Laschet
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Meder
authors.forename: François-Xavier
authors.initials: FX
authors.lastname: Roux
authors.forename: Catherine
authors.initials: C
authors.lastname: Daumas-Duport
authors.forename: Bertrand
authors.initials: B
authors.lastname: Devaux
mesh_terms: D000293:Adolescent; D000328:Adult; D017668:Age of Onset; D001921:Brain / Q000473:pathology; D001932:Brain Neoplasms / Q000150:complications / Q000473:pathology / Q000601:surgery*; D002277:Carcinoma / Q000150:complications / Q000473:pathology / Q000601:surgery*; D002648:Child; D004351:Drug Resistance; D004569:Electroencephalography; D004827:Epilepsy / Q000209:etiology / Q000473:pathology / Q000601:surgery*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D019635:Neurosurgical Procedures / Q000379:methods*; D012640:Seizures / Q000601:surgery; D025321:Surgery, Computer-Assisted / Q000379:methods*; D016896:Treatment Outcome; D055815:Young Adult