BACKGROUND AND OBJECTIVE

Awake craniotomy is often used in the surgery of glioma, the most common primary brain tumor. It has been proven to maximize the extent of tumor resection while minimizing post-operative neurologic deficits. Extensive research has been conducted on this topic, and we would like to perform a bibliometric analysis to identify the top 100 most cited articles in awake glioma surgery. Knowing the relevant and most impactful studies in the field would help clinicians streamline the evidence and determine its application in their practice.

In October 2023, we performed a title-specific search on the Scopus and PubMed databases using (“glioma*” OR “astrocytoma*” OR “glioblastoma” OR “low grade glioma” OR “high grade glioma”) and (“awake craniotomy” OR “awake surgery” OR “awake brain surgery” OR “awake neurosurgery”) as our query term without any restriction criteria. The top 100 most cited articles were identified, reviewed, and analyzed.

Our search yielded a total of 5557 articles published. The top article had a citation count of 834 and reported on functional outcome after language mapping in glioma resection. Journal of Neurosurgery had the most number of publications. Neurosurgeons (n=81) were the primary author in most publications, followed by anesthesiologists (n=22) and neurologists (n=6). Three countries (USA, France, Italy) contributed to 74% of the articles. Most of the articles were reviews and case reports/series.

This study identified the top 100 most cited articles on awake glioma surgery. The content dealt with several aspects of awake craniotomy such as brain mapping, intraoperative techniques and adjuncts, and practice recommendations. This analysis can help identify knowledge gaps and potential areas of research in glioma surgery.

Objective: To investigate the clinicopathological characteristics, pathological diagnosis and prognosis of diffuse midline glioma (DMG) with H3K27 alteration in adults. Methods: Twenty cases of H3K27-altered adult DMG diagnosed in the First Affiliated Hospital of Nanjing Medical University were enrolled from 2017 to 2022. All cases were evaluated by clinical and imaging presentations, HE, immunohistochemical staining and molecular genetics; and the relevant literature was reviewed. Results: The ratio of male to female was 1∶1, and the median age was 53 years (range from 25 to 74 years); the tumors were located in the brainstem (3/20, 15%) and non-brainstem (17/20, 85%; three in thoracolumbar spinal cord and one in pineal region). The clinical manifestations were non-specific, mostly dizziness, headache, blurred vision, memory loss, low back pain, limb sensation and/or movement disorders, etc. Microscopically, the tumors showed infiltrative growth, with WHO grade 2 (3 cases), grade 3 (12 cases), and grade 4 (5 cases). The tumors showed astrocytoma-like and oligdendroglioma-like, pilocytic astrocytoma-like and epithelioid-like patterns. Immunohistochemically, the tumor cells were positive for GFAP, Olig2 and H3K27M, and H3K27me3 expression was variably lost. ATRX expression was lost in four cases, p53 was strongly positive in 11 cases. Ki-67 index was about 5%-70%. Molecular genetics showed p. k27m mutation in exon 1 of H3F3A gene in 20 cases; BRAF mutation in two cases: V600E and L597Q mutation in one case each. Follow up intervals ranged from 1 to 58 months, and the survival time for brainstem (6.0 months) and non-brainstem (30.4 months) tumors was significantly different (P<0.05). Conclusions: DMG with H3K27 alteration is uncommonly found in adults, mostly occurs in non-brainstem, and can present in adults of all ages. Owing to the wide histomorphologic features, mainly astrocytic differentiation, routine detection of H3K27me3 in midline glioma is recommended. Molecular testing should be performed on any suspected cases to avoid missed diagnosis. Concomitant BRAF L597Q mutation and PPM1D mutation are novel findings. The overall prognosis of this tumor is poor, with tumors located in the brainstem showing worse outcome.
Humans ; Adult ; Male ; Female ; Middle Aged ; Aged ; Histones/genetics* ; Brain Neoplasms/pathology* ; Proto-Oncogene Proteins B-raf/metabolism* ; Glioma/pathology* ; Astrocytoma/pathology* ; Mutation

Subependymal giant cell astrocytoma is a rare tumor that occurs in the walls of the lateral ventricles, foramen of Monro, and less frequently, in the third ventricle. It is one of the intracranial lesions found in tuberous sclerosis complex (TSC) ─ a rare multisystem genetic disease. We present a rare case of an adult Filipino with cutaneous signs of TSC, who initially presented with signs of increased intracranial pressure. The patient underwent right frontal craniotomy, endoport-assisted excision of the tumor with insertion of a ventriculoperitoneal (VP) shunt. Histopathology was consistent with a subependymal giant-cell astrocytoma WHO grade 1. The general status of the patient improved thereafter – there was the relief of headache and improvement in vision and gross hearing. Subependymal giant cell astrocytoma is a rare tumor of the central nervous system especially in adults, whose diagnosis is based on clinical, radiological, and histological, and immunohistochemical stains. It should be included in the differential diagnosis of a mass near the foramen of Monro. Given the hereditary nature of the disease, genetic counseling is essential when encountering patients with this condition.
Astrocytoma ; Tuberous Sclerosis ; Adult ; Case report

Brain tumors are the second most common type of structural brain lesion that causes chronic epilepsy. Patients with low-grade brain tumors often experience chronic drug-resistant epilepsy starting in childhood, which led to the concept of long-term epilepsy-associated tumors (LEATs). Dysembryoplastic neuroepithelial tumor and ganglioglioma are representative LEATs and are characterized by young age of onset, frequent temporal lobe location, benign tumor biology, and chronic epilepsy. Although highly relevant in clinical epileptology, the concept of LEATs has been criticized in the neuro-oncology field. Recent genomic and molecular studies have challenged traditional views on LEATs and low-grade gliomas. Molecular studies have revealed that low-grade gliomas can largely be divided into three groups : LEATs, pediatric-type diffuse low-grade glioma (DLGG; astrocytoma and oligodendroglioma), and adult-type DLGG. There is substantial overlap between conventional LEATs and pediatric-type DLGG in regard to clinical features, histology, and molecular characteristics. LEATs and pediatric-type DLGG are characterized by mutations in BRAF, FGFR1, and MYB/MYBL1, which converge on the RAS-RAF-MAPK pathway. Gene (mutation)-centered classification of epilepsy-associated tumors could provide new insight into these heterogeneous and diverse neoplasms and may lead to novel molecular targeted therapies for epilepsy in the near future.
Age of Onset ; Astrocytoma ; Biology ; Brain ; Brain Neoplasms ; Classification ; Epilepsy ; Ganglioglioma ; Glioma ; Humans ; Molecular Targeted Therapy ; Neoplasms, Neuroepithelial ; Seizures ; Temporal Lobe

BACKGROUND: Numerous studies reported a usefulness of 5-aminolevulinic acid (5-ALA) fluorescence-guided surgery (FGS) in high grade gliomas. However, fluorescence patterns and intensities are variable among gliomas. In this study, we report our extensive experience with FGS in various gliomas, focusing on epidemiological data of fluorescence patterns. METHODS: A total of 827 histologically proven glioma patients out of 900 brain tumor patients who had undergone FGS using 5-ALA during the period of 8.5 years between July 2010 and January 2019 were analyzed. Indications of FGS in glioma surgery are evidence for possible high-grade foci in putative gliomas in preoperative MRI. RESULTS: Among the 827 gliomas, the number of cases corresponding to 2016 World Health Organization (WHO) grade IV, III, II, and I are 528 (58.7%), 193 (21.4%), 87 (9.7%) and 19 (2.1%), respectively. In terms of fluorescence rate, grade IV gliomas showed positive fluorescence in 95.4% of cases including strong intensity in 85.6%. Grade III gliomas showed fluorescence in about half of cases (55.0%), but 45.0% of the cases showed no fluorescence at all. Anaplastic oligodendroglioma had a higher positive rate (63.9%) than anaplastic astrocytoma (46.2%). Both grade II and I gliomas still showed positive fluorescence in about one-fourth of cases (24.1% and 26.3% respectively). Among them ependymoma and pilocytic astrocytoma were fluorescence-prone tumors. CONCLUSION: This epidemiological data of 5-ALA fluorescence in various grades of glioma provides a basic reference to the clinical application of FGS with 5-ALA in glioma surgery.
Astrocytoma ; Brain Neoplasms ; Ependymoma ; Fluorescence ; Glioblastoma ; Glioma ; Humans ; Magnetic Resonance Imaging ; Oligodendroglioma ; World Health Organization

BACKGROUND: Pilocytic astrocytoma (PA) is a brain tumor that is relatively more common in children and young adults. METHODS: We retrospectively reviewed the medical records of patients with PA treated at a single center between 1988 and 2018. RESULTS: We included 31 subjects with PA. The median age at diagnosis was 13.4 years, and the median follow-up duration was 9.9 years. The total PA group had a 10-year disease-specific survival (DSS) rate of 92.6% [95% confidence interval (CI), 82.6–100] and 10-year progression-free survival (PFS) rate of 52.8% (95% CI, 32.0–73.6). In patients aged <20 years, tumors were more likely to be located in sites in which gross total tumor resection (GTR) was impossible. No statistically significant difference in 10-year DSS was found between the GTR (100%) and non-GTR (89.7%; 95% CI, 76.2–100; p=0.374) groups. However, a statistically significant difference in 10-year PFS was found between the GTR (100%) and non-GTR groups (30.7%; 95% CI, 8.6–52.8; p=0.012). In the non-GTR group, no statistically significant difference in 10-year DSS was found between the patients who received immediate additional chemotherapy and/or radiotherapy (Add-Tx group, 92.9%; 95% CI, 79.4–100) and the non-Add-Tx group (83.3%; 95% CI, 53.5–100; p=0.577). No statistically significant difference in 10-year PFS was found between the Add-Tx group (28.9%; 95% CI, 1.7–56.1) and non-Add-Tx group (33.3%; 95% CI, 0–70.9; p=0.706). CONCLUSION: The PFS of the patients with PA in our study depended only on the degree of surgical excision associated with tumor location. This study is limited by its small number of patients and retrospective nature. A multicenter and prospective study is necessary to confirm these findings.
Adolescent ; Astrocytoma ; Brain Neoplasms ; Child ; Diagnosis ; Disease-Free Survival ; Drug Therapy ; Follow-Up Studies ; Glioma ; Humans ; Medical Records ; Prognosis ; Prospective Studies ; Radiotherapy ; Retrospective Studies ; Survivors ; Young Adult

BACKGROUND: There was no practical guideline for the management of patients with central nervous system tumor in Korea for many years. Thus, the Korean Society for Neuro-Oncology (KSNO), a multidisciplinary academic society, has developed the guideline for glioblastoma. Subsequently, the KSNO guideline for World Health Organization (WHO) grade II cerebral glioma in adults is established. METHODS: The Working Group was composed of 35 multidisciplinary medical experts in Korea. References were identified by searching PubMed, MEDLINE, EMBASE, and Cochrane CENTRAL databases using specific and sensitive keywords as well as combinations of keywords regarding diffuse astrocytoma and oligodendroglioma of brain in adults. RESULTS: Whenever radiological feature suggests lower grade glioma, the maximal safe resection if feasible is recommended globally. After molecular and histological examinations, patients with diffuse astrocytoma, isocitrate dehydrogenase (IDH)-wildtype without molecular feature of glioblastoma should be primarily treated by standard brain radiotherapy and adjuvant temozolomide chemotherapy (Level III) while those with molecular feature of glioblastoma should be treated following the protocol for glioblastomas. In terms of patients with diffuse astrocytoma, IDH-mutant and oligodendroglioma (IDH-mutant and 1p19q codeletion), standard brain radiotherapy and adjuvant PCV (procarbazine+lomustine+vincristine) combination chemotherapy should be considered primarily for the high-risk group while observation with regular follow up should be considered for the low-risk group. CONCLUSION: The KSNO's guideline recommends that WHO grade II gliomas should be treated by maximal safe resection, if feasible, followed by radiotherapy and/or chemotherapy according to molecular and histological features of tumors and clinical characteristics of patients.
Adult ; Astrocytoma ; Brain ; Central Nervous System ; Drug Therapy ; Drug Therapy, Combination ; Follow-Up Studies ; Glioblastoma ; Glioma ; Humans ; Isocitrate Dehydrogenase ; Korea ; Oligodendroglioma ; Radiotherapy ; World Health Organization

BACKGROUND: There was no practical guideline for the management of patients with central nervous system tumor in Korea in the past. Thus, the Korean Society for Neuro-Oncology (KSNO), a multidisciplinary academic society, developed the guideline for glioblastoma successfully and published it in Brain Tumor Research and Treatment, the official journal of KSNO, in April 2019. Recently, the KSNO guideline for World Health Organization (WHO) grade III cerebral glioma in adults has been established. METHODS: The Working Group was composed of 35 multidisciplinary medical experts in Korea. References were identified by searches in PubMed, MEDLINE, EMBASE, and Cochrane CENTRAL databases using specific and sensitive keywords as well as combinations of keywords. Scope of the disease was confined to cerebral anaplastic astrocytoma and oligodendroglioma in adults. RESULTS: Whenever radiological feature suggests high grade glioma, maximal safe resection if feasible is globally recommended. After molecular and histological examinations, patients with anaplastic astrocytoma, isocitrate dehydrogenase (IDH)-mutant should be primary treated by standard brain radiotherapy and adjuvant temozolomide chemotherapy whereas those with anaplastic astrocytoma, NOS, and anaplastic astrocytoma, IDH-wildtype should be treated following the protocol for glioblastomas. In terms of anaplastic oligodendroglioma, IDH-mutant and 1p19q-codeletion, and anaplastic oligodendroglioma, NOS should be primary treated by standard brain radiotherapy and neoadjuvant or adjuvant PCV (procarbazine, lomustine, and vincristine) combination chemotherapy. CONCLUSION: The KSNO's guideline recommends that WHO grade III cerebral glioma of adults should be treated by maximal safe resection if feasible, followed by radiotherapy and/or chemotherapy according to molecular and histological features of tumors.
Adult ; Astrocytoma ; Brain ; Brain Neoplasms ; Central Nervous System ; Drug Therapy ; Drug Therapy, Combination ; Glioblastoma ; Glioma ; Humans ; Isocitrate Dehydrogenase ; Korea ; Lomustine ; Oligodendroglioma ; Radiotherapy ; World Health Organization

BACKGROUND: The 2016 World Health Organization (WHO) classification of central nervous system (CNS) tumors has been modified to incorporate the IDH mutation and 1p/19q co-deletion in the diagnosis of diffuse gliomas. In this study, we aimed to evaluate the feasibility and prognostic significance of the revised 2016 WHO classification of CNS tumors in Mongolian patients with diffuse gliomas. METHODS: A total of 124 cases of diffuse gliomas were collected, and tissue microarray blocks were made. IDH1 mutation was tested using immunohistochemistry, and 1p/19q co-deletion status was examined using fluorescence in situ hybridization analysis. RESULTS: According to the 2016 WHO classification, 124 cases of diffuse brain glioma were reclassified as follows: 10 oligodendroglioma, IDHmut and 1p/19q co-deleted; three anaplastic oligodendroglioma, IDHmut and 1p/19q co-deleted; 35 diffuse astrocytoma, IDHmut, 11 diffuse astrocytoma, IDHwt, not otherwise specified (NOS); 22 anaplastic astrocytoma, IDHmut, eight anaplastic astrocytoma, IDHwt, NOS; and 35 glioblastoma, IDHwt, NOS, respectively. The 2016 WHO classification presented better prognostic value for overall survival in patients with grade II tumors than traditional histological classification. Among patients with grade II tumors, those with oligodendroglioma IDHmut and 1p/19q co-deleted and diffuse astrocytoma IDHmut showed significantly higher survival than those with diffuse astrocytoma IDHwt, NOS (p<.01). CONCLUSIONS: Mongolian diffuse gliomas could be reclassified according to the new 2016 WHO classification. Reclassification revealed substantial changes in diagnosis of both oligodendroglial and astrocytic entities. We have confirmed that the revised 2016 WHO CNS tumor classification has prognostic significance in Mongolian patients with diffuse gliomas, especially those with grade II tumors.
Astrocytoma ; Brain ; Central Nervous System ; Chromosome Deletion ; Classification ; Diagnosis ; Fluorescence ; Glioblastoma ; Glioma ; Global Health ; Humans ; Immunohistochemistry ; In Situ Hybridization ; Isocitrate Dehydrogenase ; Nervous System Neoplasms ; Nervous System ; Oligodendroglioma ; World Health Organization

Supratentorial extraventricular anaplastic ependymoma (SEAE) in adults is a relatively rare intracranial tumor. Because of the very low prevalence, only a few cases have been reported. According to a recent study, SEAE is associated with a poor prognosis and there is no definite consensus on optimal treatment. We report a case of an adult SEAE patient who had no recurrence until seven years after a gross total resection (GTR) followed by conventional radiotherapy. A 42-year-old male had a persistent mild headache, left facial palsy, dysarthria, and left hemiparesis. Preoperative neuroimaging revealed an anaplastic astrocytoma or supratentorial ependymoma in the right frontal lobe. A GTR was performed, followed by adjuvant radiotherapy. Histologic and immunohistochemical results revealed anaplastic ependymoma. After seven years of initial therapy, a regular follow-up MRI showed a 3-cm-sized partially cystic mass in the same area as the initial tumor. The patient underwent a craniotomy, and a GTR was performed. Histopathologic examination revealed recurrence of the SEAE. External radiotherapy was performed. The patient has been stable without any disease progression or complications for 12 months since the surgery for recurrent SEAE.
Adult ; Astrocytoma ; Consensus ; Craniotomy ; Disease Progression ; Dysarthria ; Ependymoma ; Facial Paralysis ; Follow-Up Studies ; Frontal Lobe ; Headache ; Humans ; Magnetic Resonance Imaging ; Male ; Neuroimaging ; Paresis ; Prevalence ; Prognosis ; Radiotherapy ; Radiotherapy, Adjuvant ; Recurrence ; Supratentorial Neoplasms