title: Adult-onset angiocentric glioma of epithelioid cell-predominant type of the mesial temporal lobe suggestive of a rare but distinct clinicopathological subset within a spectrum of angiocentric cortical ependymal tumors.
abstract: Angiocentric glioma (AG) is defined as an epilepsy-associated stable or slowly growing cerebral tumor primarily affecting children and young adults, histologically consisting mainly of monomorphic, bipolar spindle-shaped cells and occasional round to monopolar columnar epithelioid cells, showing angiocentric growth pattern and features of ependymal differentiation. We describe two clinicopathologically unusual cases of AG. Case 1 is a 54-year-old woman with a 10-year history of complex partial seizures. MRI revealed non-enhancing T1-low, T2/fluid-attenuated inversion recovery (FLAIR)-high intensity signal change in the left hippocampus and amygdala. After selective amygdalohippocampectomy, she had rare non-disabling seizures on medication for over 50 months (Engel's class I). Case 2 is a 37-year-old man with a 3-year history of complex partial seizures. MRI revealed non-enhancing T1-low, T2/FLAIR-high intensity signal change in the left uncus and amygdala. After combined amygdalohippocampectomy and anterior temporal lobectomy, he has been seizure-free for over 11 months. Histologically the tumors in both cases consisted mainly of infiltrating epithelioid cells (GFAP- ∼±, S-100-) with perinuclear epithelial membrane antigen (EMA)-positive dots and rings, showing conspicuous single- and multi-layered angiocentric arrangements. Occasional tumor cells showed spindle-shaped morphology (GFAP+, S-100+) with rare EMA-positive dots aligned radially and longitudinally along parenchymal blood vessels. Focal solid areas showed a Schwannoma-like fascicular arrangement with rare EMA-positive dots and/or sheets of epithelioid cells with abundant EMA dots. Electron microscopic investigation demonstrated features of ependymal differentiation. These cases, together with a few similar cases previously reported, appear to represent a rare but distinct clinicopathological subset of AG characterized by adult-onset, mesial temporal lobe localization and epithelioid cell-predominant histology.
authors.affiliation: Department of Neuropathology, Research Institute for Brain and Blood Vessels-Akita, Akita, Japan. hmiyata-nsu@umin.ac.jp
authors.forename: Hajime
authors.initials: H
authors.lastname: Miyata
authors.forename: Masae
authors.initials: M
authors.lastname: Ryufuku
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Kubota
authors.forename: Taku
authors.initials: T
authors.lastname: Ochiai
authors.forename: Kaku
authors.initials: K
authors.lastname: Niimura
authors.forename: Tomokatsu
authors.initials: T
authors.lastname: Hori
mesh_terms: D000328:Adult; D017668:Age of Onset; D000679:Amygdala / Q000473:pathology; D038481:Anterior Temporal Lobectomy; D001932:Brain Neoplasms / Q000150:complications / Q000473:pathology* / Q000601:surgery; D004806:Ependymoma / Q000473:pathology*; D017029:Epilepsy, Complex Partial / Q000209:etiology; D015622:Epithelioid Cells / Q000473:pathology*; D005260:Female; D005910:Glioma / Q000150:complications / Q000473:pathology* / Q000601:surgery; D006624:Hippocampus / Q000473:pathology; D006801:Humans; D007150:Immunohistochemistry; D008279:Magnetic Resonance Imaging; D008297:Male; D046529:Microscopy, Electron, Transmission; D008875:Middle Aged; D009419:Nerve Tissue Proteins / Q000378:metabolism; D019635:Neurosurgical Procedures; D013702:Temporal Lobe / Q000473:pathology* / Q000601:surgery; D016707:Tissue Fixation
chemical_list: D009419:Nerve Tissue Proteins