title: Lack of IDH1 mutation in astroblastomas suggests putative origin from ependymoglial cells?
abstract: Astroblastomas are extremely rare neuroepithelial tumors of uncertain histogenesis, affecting children and young adults, and constitute a new addition to the WHO 2000 classification of CNS tumors. We report the largest series of nine cases diagnosed in a single institute over the last 13 years and review published literature. Mean age at presentation was 12.8 years (range: 22 months to 27years). Seven out of nine cases were supratentorial (frontal/frontoparietal - three, parieto-occipital - three, parafalcine - one), one was intraventricular and another was optochaismatic/suprasellar. Five cases were high grade (anaplastic) astroblastomas with Ki-67 labeling index of 8-10%. Immunohistochemical and ultrastructural evidence suggesting origin from cells intermediate between ependymocytes and astrocytes is presented. The histogenetic origin of these tumors remains speculative. But the lack of Isocitrate dehydrogenase 1 (IDH1) mutation as detected by immunohistochemistry in this study, which is similar to ependymomas supports putative origin from ependymoglial cells. Out of the nine cases, recurrence was noted in one case, 12 months after gross total resection with progression to high grade in the recurrent tumor. There is no recommended treatment protocol due to the rarity of this entity and prognostic factors are yet to be established.
authors: Department of Neuropathology, National Institute of Mental Health and Neurosciences, Bangalore, India.
authors: Unchagi
authors: U
authors: Asha
authors: Department of Neuropathology, National Institute of Mental Health and Neurosciences, Bangalore, India.
authors: Anita
authors: A
authors: Mahadevan
authors: Department of Neuropathology, National Institute of Mental Health and Neurosciences, Bangalore, India.
authors: Dhinakaran
authors: D
authors: Sathiyabama
authors: Department of Neuropathology, National Institute of Mental Health and Neurosciences, Bangalore, India.
authors: Thakkar
authors: T
authors: Ravindra
authors: Department of Neuropathology, National Institute of Mental Health and Neurosciences, Bangalore, India.
authors: B K Chandrashekar
authors: BK
authors: Sagar
authors: Department of Neurosurgery, National Institute of Mental Health and Neurosciences, Bangalore, India.
authors: Dhananjaya Ishwar
authors: DI
authors: Bhat
authors: Neuroimaging & Interventional Radiology, National Institute of Mental Health and Neurosciences, Bangalore, India.
authors: Hanumantapura Ramalingaiah
authors: HR
authors: Aravinda
authors: Department of Neurosurgery, National Institute of Mental Health and Neurosciences, Bangalore, India.
authors: Paritosh
authors: P
authors: Pandey
authors: Department of Neurosurgery, Sree Chitra Tirunal Institute for Medical Sciences & Technology, Trivandrum, India.
authors: George C
authors: GC
authors: Vilanilam
mesh_terms: D000293:Adolescent; D000328:Adult; D001932:Brain Neoplasms / Q000235:genetics* / Q000648:ultrastructure*; D002648:Child; D002675:Child, Preschool; D063928:Ependymoglial Cells / Q000648:ultrastructure*; D005260:Female; D006801:Humans; D007223:Infant; D007521:Isocitrate Dehydrogenase / Q000235:genetics*; D008297:Male; D009154:Mutation; D018302:Neoplasms, Neuroepithelial / Q000209:etiology / Q000235:genetics* / Q000648:ultrastructure*; D055815:Young Adult
chemical_list: D007521:Isocitrate Dehydrogenase; C543588:IDH1 protein, human
keywords: IDH1 mutation; astroblastoma; ependymoglial cells; neuroepithelial tumor; ultrastructure