The World Health Organization (WHO) classification of central nervous system (CNS) tumors was revised in 2016 with a basis on the integrated diagnosis of molecular genetics. We herein provide the guidelines for using molecular genetic tests in routine pathological practice for an accurate diagnosis and appropriate management. While astrocytomas and IDH-mutant (secondary) glioblastomas are characterized by the mutational status of IDH, TP53, and ATRX, oligodendrogliomas have a 1p/19q codeletion and mutations in IDH, CIC, FUBP1, and the promoter region of telomerase reverse transcriptase (TERTp). IDH-wildtype (primary) glioblastomas typically lack mutations in IDH, but are characterized by copy number variations of EGFR, PTEN, CDKN2A/B, PDGFRA, and NF1 as well as mutations of TERTp. High-grade pediatric gliomas differ from those of adult gliomas, consisting of mutations in H3F3A, ATRX, and DAXX, but not in IDH genes. In contrast, well-circumscribed low-grade neuroepithelial tumors in children, such as pilocytic astrocytoma, pleomorphic xanthoastrocytoma, and ganglioglioma, often have mutations or activating rearrangements in the BRAF, FGFR1, and MYB genes. Other CNS tumors, such as ependymomas, neuronal and glioneuronal tumors, embryonal tumors, meningothelial, and other mesenchymal tumors have important genetic alterations, many of which are diagnostic, prognostic, and predictive markers and therapeutic targets. Therefore, the neuropathological evaluation of brain tumors is increasingly dependent on molecular genetic tests for proper classification, prediction of biological behavior and patient management. Identifying these gene abnormalities requires cost-effective and high-throughput testing, such as next-generation sequencing. Overall, this paper reviews the global guidelines and diagnostic algorithms for molecular genetic testing of brain tumors.
Adult ; Astrocytoma ; Brain Neoplasms* ; Brain* ; Central Nervous System ; Child ; Classification ; Diagnosis ; Ependymoma ; Ganglioglioma ; Genes, myb ; Glioblastoma ; Glioma ; Humans ; Molecular Biology ; Neoplasms, Neuroepithelial ; Neurons ; Oligodendroglioma ; Promoter Regions, Genetic ; Telomerase ; World Health Organization

Astroblastoma is an uncommon glial tumor with predominant manifestation in the young age. Herein, we report a case of 18-year-old astroblastoma female patient who presented with history of two months headache. Magnetic resonance imaging (MRI) of the brain demonstrated well circumscribed, intra-axial abnormal signal intensity lesion (size=5×4 cm²) in the right parieto-occipital region of the brain. The patient underwent complete surgical resection of the gross tumor, as confirmed by an early post-surgical MRI (i.e., within 24 hours of surgery). Histopathological examination revealed neoplastic lesion exhibiting perivascular pseudo-rosettes with centrally hyalinized blood vessel and focal nuclear pleomorphism. Immunohistochemistry staining illustrated reactivity for glial fibrillary acidic protein and integrase interactor 1 (INI-1). These features rendered the diagnosis of astroblastoma. A comprehensive review of the current literature to summarize the clinicopathological and radiological characteristics, prognostic factors and current treatment strategies of astroblastomas is also presented. Our study would expand the pool of this uncommon tumor towards its better understanding and optimal treatment.
Adolescent ; Blood Vessels ; Brain ; Brain Neoplasms ; Craniotomy ; Diagnosis ; Female* ; Glial Fibrillary Acidic Protein ; Headache ; Humans ; Hyalin ; Immunohistochemistry ; Integrases ; Magnetic Resonance Imaging ; Neoplasms, Neuroepithelial*

Pilocytic astrocytomas (PAs) are World Heath Organization Grade I tumors and are most common in children. PA calcification is not a common finding and has been reported more frequently in the optic nerve, hypothalamic/thalamus and superficially located cerebral tumors. We present a cerebellar PA in a 3-year-old male patient with cystic components and massive calcification areas. The residual tumor grew rapidly after the first operation, and the patient was operated on again. A histopathological examination revealed polar spongioblastoma-like cells. Massive calcification is not a common feature in PAs and can lead to difficulties in radiological and pathological differential diagnoses.
Astrocytoma* ; Child ; Child, Preschool ; Diagnosis, Differential ; Humans ; Male ; Neoplasm, Residual ; Neoplasms, Neuroepithelial ; Optic Nerve ; Recurrence*

Adult ; Biopsy ; Cerebral Ventricle Neoplasms ; diagnosis ; Diagnosis, Differential ; Humans ; Magnetic Resonance Imaging ; methods ; Male ; Neoplasms, Neuroepithelial ; diagnosis ; Third Ventricle ; diagnostic imaging

Dysembryoplastic neuroepithelial tumor (DNT) is a benign glioneuronal neoplasm that most commonly occurs in children and young adults and may present with medically intractable, chronic seizures. Radiologically, this tumor is characterized by a cortical topography and lack of mass effect or perilesional edema. Partial complex seizures are the most common presentation. Three histologic subtypes of DNTs have been described. Histologically, the recognition of a unique, specific glioneuronal element in brain tumor samples from patients with medically intractable, chronic epilepsy serves as a diagnostic feature for complex or simple DNT types. However, nonspecific DNT has diagnostic difficulty because its histology is indistinguishable from conventional gliomas and because a specific glioneuronal element and/or multinodularity are absent. This review will focus on the clinical, radiographic, histopathological, and immunohistochemical features as well as the molecular genetics of all three variants of DNTs. The histological and cytological differential diagnoses for this lesion, especially the nonspecific variant, will be discussed.
Brain Neoplasms ; Child ; Diagnosis, Differential ; Edema ; Epilepsy ; Glioma ; Humans ; Microtubule-Associated Proteins ; Molecular Biology ; Neoplasms, Neuroepithelial* ; Seizures ; Young Adult

Adult ; Female ; Humans ; Neoplasms, Neuroepithelial ; diagnosis

This study was performed to assess the usefulness of magnetoencephalography (MEG) as a presurgical evaluation modality in Korean pediatric patients with lesional localization-related epilepsy. The medical records and MEG findings of 13 pediatric patients (6 boys and 7 girls) with localization-related epilepsy, who underwent epilepsy surgery at Seoul National University Children's Hospital, were retrospectively reviewed. The hemispheric concordance rate was 100% (13/13 patients). The lobar or regional concordance rate was 77% (10/13 patients). In most cases, the MEG spike sources were clustered in the proximity of the lesion, either at one side of the margin (nine patients) or around the lesion (one patient); clustered spike sources were distant from the lesion in one patient. Among the patients with clustered spike sources near the lesion, further extensions (three patients) and distal scatters (three patients) were also observed. MEG spike sources were well lateralized and localized even in two patients without focal epileptiform discharges in the interictal scalp electroencephalography. Ten patients (77%) achieved Engel class I postsurgical seizure outcome. It is suggested that MEG is a safe and useful presurgical evaluation modality in pediatric patients with lesion localization-related epilepsy.
Adolescent ; Brain/radionuclide imaging ; Brain Diseases/pathology ; Child ; Child, Preschool ; Epilepsies, Partial/pathology/*surgery ; Female ; Ganglioglioma/pathology ; Humans ; Infant ; Magnetic Resonance Imaging ; *Magnetoencephalography ; Male ; Malformations of Cortical Development/pathology ; Neoplasms, Neuroepithelial/pathology ; Positron-Emission Tomography ; Retrospective Studies ; Seizures/diagnosis

OBJECTIVETo study the clinicopathologic features, radiologic findings, treatment options and prognosis of dysembryoplastic neuroepithelial tumor (DNT).

METHODSThe clinicopathologic and radiologic features were retrospectively analyzed in 10 cases of DNT.

RESULTSIntractable partial seizure was the main presenting symptom in all patients. The tumor was located in temporal lobe (number = 5), frontal lobe (number = 3) or parietal lobe (number = 2). CT scan displayed a hypodense lesion. MRI scan revealed the tumor was non-enhancing T1WI hypointense and T2WI hyperintense, with internal septation and hyperintense ring around the tumor seen on FLAIR image. There was neither peritumoral edema nor mass effect. Histologically, the tumor showed the presence of glioneuronal element, with oligodendrocyte-like cells, floating neurons, astrocytes and associated microcystic changes. Immunohistochemical study demonstrated positivity for NeuN and synaptophysin in the neurons and some oligodendrocyte-like cells. Olig2 and S-100 protein were also expressed in the oligodendrocyte-like cells. Ki-67 index were lower than 1% in all cases. Nine cases were treated by complete surgical excision and the remaining case was subtotally excised. No post-operative chemotherapy or radiotherapy was given. One of the 10 cases recurred on follow up.

CONCLUSIONSCorrect diagnosis of DNT requires correlation with clinicopathologic, radiologic and immunohistochemical findings. Complete resection of the tumor and epileptogenic foci is the mainstay of treatment for DNT, with intraoperative EEG monitoring. Post-operative chemotherapy or radiotherapy is not required.

Adolescent ; Adult ; Antigens, Nuclear ; metabolism ; Basic Helix-Loop-Helix Transcription Factors ; metabolism ; Brain Neoplasms ; diagnosis ; metabolism ; pathology ; surgery ; Cerebral Cortex ; metabolism ; pathology ; Child ; Female ; Follow-Up Studies ; Humans ; Magnetic Resonance Imaging ; Male ; Neoplasms, Neuroepithelial ; diagnosis ; metabolism ; pathology ; surgery ; Nerve Tissue Proteins ; metabolism ; Neurosurgical Procedures ; Oligodendrocyte Transcription Factor 2 ; Retrospective Studies ; S100 Proteins ; metabolism ; Synaptophysin ; metabolism ; Tomography, X-Ray Computed ; Young Adult

Dysembryoplastic neuroepithelial tumors (DNETs) arise mostly in the supratentorial cerebral cortex. A very rare case of intraventricular DNET with diffuse ependymal involvement, which causes spinal drop metastasis, is presented.
Adult ; Diagnosis, Differential ; Ependymoma/*pathology/radiotherapy ; Female ; Humans ; Lumbosacral Region/*pathology ; *Magnetic Resonance Imaging ; Neuroepithelial Cells/pathology ; Spinal Neoplasms/radiotherapy/*secondary

Astrocytoma ; blood supply ; pathology ; Capillaries ; pathology ; Central Nervous System Neoplasms ; blood supply ; pathology ; Diagnosis, Differential ; Ependymoma ; blood supply ; pathology ; Glioblastoma ; blood supply ; pathology ; Hemangioblastoma ; blood supply ; pathology ; Humans ; Hyperplasia ; Microvessels ; pathology ; Neoplasms, Neuroepithelial ; blood supply ; pathology ; Oligodendroglioma ; blood supply ; pathology ; Paraganglioma ; blood supply ; pathology