title: Three cases of right frontal megalencephaly: Clinical characteristics and long-term outcome.
abstract: OBJECTIVE
  To delineate the clinical and neuroimaging characteristics of localized megalencephaly involving the right frontal lobe.
  
  
  METHODS
  Data from three patients aged 14-16 years at the last follow-up were retrospectively reviewed.
  
  
  RESULTS
  All the patients were normal on neurological examination with no signs of hemiparesis. Enlargement of the right frontal lobe with increased volume of subcortical and deep white matter, as well as thickening of the ipsilateral genu of the corpus callosum was common. The onset of epilepsy was 4-7 years of age, with seizure types of massive myoclonus in two and generalized tonic-clonic in two, which could be eventually controlled by antiepileptics. Interictal electroencephalography showed frontal alpha-like activity in one, and abundant spike-wave complexes resulting in diffuse continuous spike-wave activity during sleep in two patients even after suppression of clinical seizures. Psychomotor development appeared unaffected or slightly delayed before the onset of epilepsy, but became mildly disturbed during follow-up period of 7-11 years.
  
  
  CONCLUSIONS
  Certain patients with right frontal megalencephaly can present with a milder epileptic and intellectual phenotype among those with localized megalencephaly and holohemispheric hemimegalencephaly, whose characteristic as epileptic encephalopathy was assumed from this study.
authors.affiliation: Division of Child Neurology, Institute of Neurological Sciences, Faculty of Medicine, Tottori University, Yonago, Japan.
authors.forename: Yoichi
authors.initials: Y
authors.lastname: Ono
authors.affiliation: Division of Child Neurology, Institute of Neurological Sciences, Faculty of Medicine, Tottori University, Yonago, Japan. Electronic address: saitoyo@med.tottori-u.ac.jp.
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Saito
authors.affiliation: Division of Child Neurology, Institute of Neurological Sciences, Faculty of Medicine, Tottori University, Yonago, Japan.
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Maegaki
authors.affiliation: Department of Pediatrics, Epilepsy Center, Nishi-Niigata Chuo National Hospital, Niigata, Japan.
authors.forename: Jun
authors.initials: J
authors.lastname: Tohyama
authors.affiliation: Division of Child Neurology, Institute of Neurological Sciences, Faculty of Medicine, Tottori University, Yonago, Japan.
authors.forename: Hesham
authors.initials: H
authors.lastname: Montassir
authors.affiliation: Division of Radiology, Faculty of Medicine, Tottori University, Yonago, Japan.
authors.forename: Shinya
authors.initials: S
authors.lastname: Fujii
authors.affiliation: Department of Child Neurology, National Center of Neurology and Psychiatry, Kodaira, Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Sugai
authors.affiliation: Division of Child Neurology, Institute of Neurological Sciences, Faculty of Medicine, Tottori University, Yonago, Japan.
authors.forename: Kousaku
authors.initials: K
authors.lastname: Ohno
mesh_terms: D000293:Adolescent; D000927:Anticonvulsants / Q000627:therapeutic use; D004569:Electroencephalography; D004827:Epilepsy / Q000188:drug therapy / Q000473:pathology; D005260:Female; D005625:Frontal Lobe / Q000000981:diagnostic imaging / Q000473:pathology*; D065705:Hemimegalencephaly / Q000175:diagnosis / Q000000981:diagnostic imaging / Q000188:drug therapy; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D058627:Megalencephaly / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000188:drug therapy; D012189:Retrospective Studies; D012640:Seizures / Q000188:drug therapy / Q000473:pathology; D016896:Treatment Outcome
chemical_list: D000927:Anticonvulsants
keywords: Frontal lobe; Hemimegalencephaly; Localized megalencephaly