title: Olig2 is useful in the differential diagnosis of oligodendrogliomas and extraventricular neurocytomas.
abstract: A 42-year-old woman had suffered from headaches since April 2009. Computed tomography revealed a tumor with marked calcification in the left frontal lobe adjacent to the left anterior horn of the lateral ventricle. T1-weighted gadolinium-enhanced magnetic resonance imaging showed a well-enhanced tumor at the lesion. Dynamic methionine positron emission tomography showed no delayed methionine attenuation. Initial preoperative diagnosis was extraventricular neurocytoma (EVN). However, oligodendroglioma was determined upon a second diagnosis. The patient underwent total tumor removal. Hematoxylin and eosin staining showed the characteristic fried egg-like cells, round nuclei, and immunohistochemically, the tumor cells were positive for glial fibrillary acidic protein, synaptophysin, neuronal nuclear antigen, microtubule-associated protein 2 and Olig2. The MIB-1 labeling index was 20%, which suggested malignancy. Although these findings demonstrated that the tumor had glioneuronal character, it was difficult to differentiate between EVN and oligodendroglioma. There have been reports that Olig2 immunohistochemistry is generally positive in cases of oligodendroglioma, but not in cases of neurocytoma. We completed the diagnosis as oligodendroglioma. Subsequent electron microscopy results presented oligodendroglial but not neuronal characteristics. We concluded that Olig2 is useful in the differential diagnosis of oligodendrogliomas and EVNs.
authors.affiliation: Department of Neurosurgery, Gifu University Graduate School of Medicine, Gifu, Japan. emac800jp@yahoo.co.jp
authors.forename: Makoto
authors.initials: M
authors.lastname: Okada
authors.forename: Hirohito
authors.initials: H
authors.lastname: Yano
authors.forename: Yoshinobu
authors.initials: Y
authors.lastname: Hirose
authors.forename: Noriyuki
authors.initials: N
authors.lastname: Nakayama
authors.forename: Naoyuki
authors.initials: N
authors.lastname: Ohe
authors.forename: Jun
authors.initials: J
authors.lastname: Shinoda
authors.forename: Toru
authors.initials: T
authors.lastname: Iwama
mesh_terms: D000328:Adult; D051792:Basic Helix-Loop-Helix Proteins / Q000032:analysis*; D014408:Biomarkers, Tumor / Q000032:analysis; D001932:Brain Neoplasms / Q000175:diagnosis* / Q000473:pathology / Q000601:surgery; D003937:Diagnosis, Differential; D005260:Female; D005904:Glial Fibrillary Acidic Protein / Q000032:analysis; D006801:Humans; D007150:Immunohistochemistry; D008279:Magnetic Resonance Imaging; D008854:Microscopy, Electron; D008869:Microtubule-Associated Proteins / Q000032:analysis; D009419:Nerve Tissue Proteins / Q000032:analysis*; D018306:Neurocytoma / Q000175:diagnosis* / Q000473:pathology / Q000601:surgery; D000076104:Oligodendrocyte Transcription Factor 2; D009836:Oligodendroglia / Q000378:metabolism / Q000473:pathology / Q000648:ultrastructure*; D009837:Oligodendroglioma / Q000175:diagnosis* / Q000473:pathology / Q000601:surgery; D016708:Synaptophysin / Q000032:analysis
chemical_list: D051792:Basic Helix-Loop-Helix Proteins; D014408:Biomarkers, Tumor; D005904:Glial Fibrillary Acidic Protein; D008869:Microtubule-Associated Proteins; D009419:Nerve Tissue Proteins; D000076104:Oligodendrocyte Transcription Factor 2; D016708:Synaptophysin; C489788:MAP2 protein, human; C405708:OLIG2 protein, human