title: Challenging diagnosis: oligodendroglioma versus extraventricular neurocytoma.
abstract: Diagnosis of oligodendroglioma from other clear cell neoplasms of central nervous system (CNS) is still challenging despite advances in neuroradiology and molecular diagnostic tools. Herein, we present a 44-year-old male patient who had a diagnosis of right parietal oligodendroglioma grade II in 1994 which recurred in 2002. He presented with intratumoral hemorrhage and he underwent radical resection of tumor in 2003. Histopathological examination of the recurrent tumor showed anaplastic progression with confusing immunohistochemical (IHC) results; the tumor was positive for NeuN and synaptophysin staining. The question arisen was whether the recurrent tumor was an oligodendroglioma with neuronal differentiation or an extraventricular neurocytoma initially misdiagnosed as oligodendroglioma. Repeated IHC staining showed negative results for NeuN and synaptophysin. Chromosomal analysis revealed 1p/19q deletion, which led to the diagnosis ofanaplastic oligodendroglioma grade III. Accurate diagnosis of oligodendroglioma is crucial due to recent advances and promises in its treatment. Current diagnostic methods of oligodendroglial tumors are discussed in context of differentiating oligodendrogliomas from other clear cell neoplasms of CNS, especially from extraventricular neurocytomas.
authors.affiliation: Department of Neurosurgery, Hacettepe University Institute of Neurological and Psychiatric Sciences, Hacettepe University, Sihhiye Ankara, Turkey. melikem@hacettepe.edu.tr
authors.forename: M
authors.initials: M
authors.lastname: Mut
authors.forename: G
authors.initials: G
authors.lastname: Güler-Tezel
authors.forename: M B S
authors.initials: MB
authors.lastname: Lopes
authors.forename: B
authors.initials: B
authors.lastname: Bilginer
authors.forename: I
authors.initials: I
authors.lastname: Ziyal
authors.forename: O E
authors.initials: OE
authors.lastname: Ozcan
mesh_terms: D000328:Adult; D001932:Brain Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D002872:Chromosome Deletion; D002878:Chromosomes, Human, Pair 1 / Q000235:genetics; D002888:Chromosomes, Human, Pair 19 / Q000235:genetics; D003937:Diagnosis, Differential; D006801:Humans; D007150:Immunohistochemistry; D017404:In Situ Hybridization, Fluorescence; D008279:Magnetic Resonance Imaging; D008297:Male; D009364:Neoplasm Recurrence, Local / Q000378:metabolism / Q000473:pathology*; D009419:Nerve Tissue Proteins / Q000096:biosynthesis; D018306:Neurocytoma / Q000473:pathology*; D009837:Oligodendroglioma / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D016708:Synaptophysin / Q000096:biosynthesis
chemical_list: D009419:Nerve Tissue Proteins; D016708:Synaptophysin