title: Atypical extraventricular neurocytoma in a 3-year-old girl: case report with radiological-pathological correlation.
abstract: BACKGROUND
  Extraventricular neurocytoma (EVN) is a rare neuronal tumor histologically similar to central neurocytoma but arising in the brain parenchyma outside the ventricles. The minority of EVNs show atypical features including increased proliferative index, microvascular proliferation, or necrosis, and are called atypical EVN. Most of atypical EVNs occur in adults, and the tumors in children are extremely rare. A radiological-pathological correlation and radiological clue to atypical EVNs have not been clarified.
  
  
  METHODS
  We report a case of atypical EVN in a 3-year-old girl. Magnetic resonance imaging (MRI) revealed an extraventricular intraparenchymal tumor in the left frontal lobe, which was composed of homogeneous well-demarcated cystic component and peripheral ill-delineated solid component with enhancement. Angiography demonstrated vascular proliferation and arteriovenous shunting in the tumor. Histologically, the resected tumor was diagnosed as atypical EVN. Types of the tumor borders (well-circumscribed or infiltrative) and MRI findings correlated closely. Morphology of the tumor vasculature was remarkable for microvascular proliferation and dilated, thickened veins, which corresponded to the angiographic features.
  
  
  CONCLUSIONS
  Although rare, atypical EVN should be included in the differential diagnosis of a cystic mass in the cerebral hemispheres in children. Radiological evaluation of tumor borders and angiographic characteristics might be useful for predicting atypicality of the tumor.
authors.affiliation: Department of Basic Laboratory Sciences, Yamaguchi University Graduate School of Medicine, Ube, Japan.
authors.forename: Hiroo
authors.initials: H
authors.lastname: Kawano
authors.forename: Tokuhiro
authors.initials: T
authors.lastname: Kimura
authors.forename: Koji
authors.initials: K
authors.lastname: Iwata
authors.forename: Matakazu
authors.initials: M
authors.lastname: Furukawa
authors.forename: Sadahiro
authors.initials: S
authors.lastname: Nomura
authors.forename: Aya
authors.initials: A
authors.lastname: Ishii
authors.forename: Shinsuke
authors.initials: S
authors.lastname: Tanaka
authors.forename: Yoshinobu
authors.initials: Y
authors.lastname: Hoshii
authors.forename: Michiyasu
authors.initials: M
authors.lastname: Suzuki
authors.forename: Eiji
authors.initials: E
authors.lastname: Ikeda
mesh_terms: D001932:Brain Neoplasms / Q000473:pathology*; D002675:Child, Preschool; D005260:Female; D006801:Humans; D018810:Magnetic Resonance Angiography; D008279:Magnetic Resonance Imaging; D018306:Neurocytoma / Q000473:pathology*; D016708:Synaptophysin / Q000378:metabolism
chemical_list: D016708:Synaptophysin