Adult brainstem gliomas

Comprehensive Morphometric Analysis of the Rhomboid Fossa: Implications for Safe Entry Zones in Brainstem Surgery

BACKGROUND

The rhomboid fossa (RF) is a crucial anatomical region in brainstem surgery as it contains essential structures such as the reticular formation and cranial nerve nuclei. This study aimed to provide a detailed understanding of the complex microsurgical anatomy of the RF, which is vital for the safe execution of neurosurgical procedures.

METHODS

Morphometric analysis was conducted on 45 adult human brainstems preserved in 10% formalin. Under 20× magnification, 13 linear measurements were performed using a millimeter graph to identify key anatomical landmarks.

RESULTS

The RF measured 34.65 mm in length and 22.61 mm in width. The facial colliculus measured 4.26 mm in length on the left and 4.45 mm on the right, with corresponding widths of 3.77 mm and 3.50 mm. The distance between the sulcus limitans incisures was 9.52 mm, and the distance from the upper border of the medullary striae to obex was 11.53 mm. The proximity of the facial colliculus to the median sulcus was measured at 0.86 mm on the right and 0.96 mm on the left. Additionally, 2 safe entry zones-the suprafacial and infrafacial triangles-were identified, offering pathways to reach dorsal pons lesions through the RF.

CONCLUSIONS

This comprehensive morphometric analysis of the RF enhances the understanding of its intricate anatomy. By describing safe entry zones, the suprafacial and infrafacial triangles, and providing precise measurements of key anatomical features, this study serves as a valuable resource for neurosurgeons in planning and executing brainstem surgeries.

Clinical characteristics and prognostic factors of adult brainstem gliomas: A retrospective analysis of histologically-proven 40 cases

To illustrate the clinical characteristics and prognostic factors of adult patients pathologically confirmed with brainstem gliomas (BSGs). Clinical data of 40 adult patients pathologically diagnosed with BSGs admitted to Beijing Shijitan Hospital from 2009 to 2022 were recorded and retrospectively analyzed. The primary parameters included relevant symptoms, duration of symptoms, Karnofsky performance status (KPS), tumor location, type of surgical resection, diagnosis, treatment, and survival. Univariate and multivariate analyses were evaluated by Cox regression models. The gliomas were located in the midbrain of 9 patients, in the pons of 14 cases, in the medulla of 5 cases, in the midbrain and pons of 6 cases and invading the medulla and pons of 6 cases, respectively. The proportion of patients with low-grade BSGs was 42.5%. Relevant symptoms consisted of visual disturbance, facial paralysis, dizziness, extremity weakness, ataxia, paresthesia, headache, bucking, dysphagia, dysacousia, nausea, dysphasia, dysosmia, hypomnesia and nystagmus. 23 (57.5%) patients accepted stereotactic biopsy, 17 (42.5%) patients underwent surgical resection. 39 patients received radiotherapy and 34 cases were treated with temozolomide. The median overall survival (OS) of all patients was 26.2 months and 21.5 months for the median progression-free survival (PFS). Both duration of symptoms (P = .007) and tumor grading (P = .002) were the influencing factors for OS, and tumor grading was significantly associated with PFS (P = .001). Duration of symptoms for more than 2 months and low-grade are favorable prognostic factors for adult patients with BSGs.

NTMS based tractography and segmental diffusion analysis in patients with brainstem gliomas: Risk stratification and clinical potential

Introduction

Surgery on the brainstem level is associated with a high-risk of postoperative morbidity. Recently, we have introduced the combination of navigated transcranial magnetic stimulation (nTMS) and diffusion tensor imaging (DTI) tractography to define functionally relevant motor fibers tracts on the brainstem level to support operative planning and risk stratification in brainstem cavernomas.

Research question

Evaluate this method and assess it's clinical impact for the surgery of brainstem gliomas.

Material and methods

Patients with brainstem gliomas were examined preoperatively with motor nTMS and DTI tractography. A fractional anisotropy (FA) value of 75% of the individual FA threshold (FAT) was used to track descending corticospinal (CST) and -bulbar tracts (CBT). The distance between the tumor and the somatotopic tracts (hand, leg, face) was measured and diffusion parameters were correlated to the patients' outcome.

Results

12 patients were enrolled in this study, of which 6 underwent surgical resection, 5 received a stereotactic biopsy and 1 patient received conservative treatment. In all patients nTMS mapping and somatotopic tractography were performed successfully. Low FA values correlated with clinical symptoms revealing tract alteration by the tumor (p = 0.049). A tumor-tract distance (TTD) above 2 mm was the critical limit to achieve a safe complete tumor resection.

Discussion and conclusion

nTMS based DTI tractography combined with local diffusion analysis is a valuable tool for preoperative visualization and functional assessment of relevant motor fiber tracts, improving planning of safe entry corridors and perioperative risk stratification in brainstem gliomas tumors. This technique allows for customized treatment strategy to maximize patients' safety.

An uncommon presentation of early brainstem high-grade glioma in a 33-year-old male: A case study and review of literature

INTRODUCTION AND IMPORTANCE

Unlike children, high-grade brainstem glioma (HG-BSG) in adults is a rare and diverse group of tumors. They can be classified based on their location and physical characteristics, which distinguishes them from pediatric brainstem gliomas. They are rare in adults, constituting only 1 % to 2 % of intracranial gliomas. They are often aggressive and have a poor prognosis, with a median survival time of 24 months. The diagnosis of brainstem gliomas typically involves a combination of clinical evaluation and imaging studies, mainly magnetic resonance imaging (MRI), which provides detailed images and can help identify the characteristics of the tumor.

CASE PRESENTATION AND METHODS

We present a case study of an uncommon presentation of an early stage of HG-BSG in a 33-year-old male, who had a contrast-enhancing lesion in the ventrolateral medulla that extended to the lower aspect of the fourth ventricle and caused ventricular compression.

CLINICAL DISCUSSION

The findings were consistent with the literature on the current state of HG-BSG MRI findings, which typically show contrast-enhancing, hyperintense, and infiltrative lesions that involve the pons, midbrain, or medulla oblongata. The diagnosis of HG-BSG was based on clinical and radiological criteria, as the patient refused to undergo a surgical biopsy. We also performed a literature review on the current state of brainstem HG-BSG MRI findings, summarizing the main features and patterns of these tumors.

CONCLUSION

MRI can offer useful information regarding the tumor's location, size, and features, as well as its impact on surrounding tissues and cerebrospinal fluid circulation.

The Infratrigeminal Suprafloccular Approach to Intrapontine Lesions: An Anatomical Overview and Relevance for the Approach to Intrapontine Lesions

Background and objectives Brainstem lesions have long been considered complex pathologies that may lead to permanent deficits or life-threatening complications, posing significant challenges for surgical removal. Among these lesions, intrapontine lesions are particularly challenging in the field of neurosurgery. However, with advancements in microsurgical anatomy knowledge and technology, these lesions have become more amenable to surgical treatment. In this study, the authors examine an infratrigeminal suprafloccular approach, which has been shown to be a safe surgical route, resulting in fewer postoperative complications, while evaluating the anatomical nuances of the approach and route. Methods Twenty cadaveric brainstem specimens were analyzed to assess the anatomy, focusing on the lateral aspect of the pons as a potential safe entry zone for intrapontine lesions. The authors consistently analyzed twenty brainstem specimens, carefully examining the pontine microsurgical anatomy. A triangular area of entrance was measured, with three sides or walls (X, Y, and Z) aiming to identify the safe zone that would spare the distinct pontine nuclei, ascending sensory pathways, corticospinal, corticonuclear, and corticopontine tracts of the brainstem. An illustrative case was adapted to the described safe entry zone for corroboration purposes. Results The authors measured three distinct lines on the lateral surface of the pons, named X, Y, and Z, forming a triangle in shape. Line X extended from the midpoint anteroposteriorly of the flocculus of the cerebellum to the apparent trigeminal exit in the lateral aspect of the pons. Line Y ran from the trigeminal exit in the pons to the apparent exit of the facial-vestibulocochlear complex in the far lateral aspect of the pontomedullary sulcus in the cerebellopontine fissure. Line Z represented the measurement from the vestibulocochlear complex to the midpoint anteroposteriorly of the flocculus of the cerebellum. The mean measurements were as follows: X = 14.41mm (range: 10mm to 20mm), Y = 13.1mm (range: 10mm to 21mm), and Z = 3mm (range: 2mm to 5mm). The mean surface area of the analyzed specimens within the triangle (formed by X, Y, and Z) was 20.1mm² (range: 10mm² to 40mm²). This area was identified as a safe zone for the entry of microsurgical approaches to intrapontine lesions, involving less retraction of the anterior pons and potentially sparing critical structures, such as the corticospinal tracts, pontine perforating arteries, tegmentum pontis, cranial nerve nuclei, substantia reticulata dorsally, and transverse pontine fibers. Microsurgical anatomical findings, combined with intraoperative monitoring in an illustrative case, consistently demonstrated that this entry area predicted less functional instability of the analyzed tracts and resulted in fewer postoperative complications. Conclusion Deep-seated pontine lesions present a complex range of pathologies with a high potential for devastating outcomes, particularly those involving hemorrhage. This study identifies and describes a presumed safe entry zone that allows for the creation of a surgical corridor for biopsy or microsurgical resection of these lesions, reducing morbidity in a previously considered impenetrable region.

The Role of Advanced MRI Sequences in the Diagnosis and Follow-Up of Adult Brainstem Gliomas: A Neuroradiological Review

The 2021 WHO (World Health Organization) classification of brain tumors incorporated the rapid advances in the molecular, genetic, and pathogenesis understanding of brain tumor pathogenesis, behavior, and treatment response. It revolutionized brain tumor classification by placing great emphasis on molecular types and completely splitting adult-type and pediatric-type diffuse gliomas. Brainstem gliomas (BSGs) are the leading primary tumors of the brainstem, although they are quite uncommon in adults compared with the pediatric population, representing less than 2% of adult gliomas. Surgery is not always the treatment of choice since resection is rarely feasible and does not improve overall survival, and biopsies are not generally performed since the location is treacherous. Therefore, MRI (Magnetic Resonance Imaging) without and with gadolinium administration represents the optimal noninvasive radiological technique to suggest brainstem gliomas diagnosis, plan a multidisciplinary treatment and for follow-up evaluations. The MRI protocol encompasses morphological sequences as well as functional and advanced sequences, such as DWI/ADC (Diffusion-Weighted Imaging/Apparent Diffusion Coefficient), DTI (Diffusion Tensor Imaging), PWI (Perfusion-Weighted Imaging), and MRS (Magnetic Resonance Spectroscopy), which improve the accuracy of the diagnosis of BSGs by adding substantial information regarding the cellularity, the infiltrative behavior toward the v fiber tracts, the vascularity, and the molecular changes. Brainstem gliomas have been divided into four categories on the basis of their MRI radiological appearance, including diffuse intrinsic low-grade gliomas, enhancing malignant gliomas, localized tectal gliomas, and other forms. The aim of our review is to provide insight into the role of advanced MRI sequences in the diagnosis and follow-up of adult brainstem gliomas.

Radiotherapy combined or not with chemotherapy in adult or pediatric patients with brainstem glioma: a population-based study

Background

The purpose of this study was to assess the treatment outcomes and prognostic factors of brainstem glioma (BCG) patients treated by radiotherapy (RT) or chemoradiation (CHRT) in the last 20 years in a population cohort.

Materials and methods

Patients diagnosed with BSG from 2000-2020 treated by RT or CHRT were identified from The Fundação Oncocentro de São Paulo database. Data on age, gender, practice setting, period of treatment, and treatment modality were extracted. The overall survival (OS) was estimated, and the subgroups were compared with the log-rank test. Cox proportional test was used in multivariate analysis.

Results

A total of 253 patients with a median follow-up of 12 months were included. There were 197 pediatric and 56 adult patients. For the entire cohort, the 1 and 3-year OS was 46%, and 23%, with a median OS of 11 months. In the subgroup analysis, adults had a median survival of 33 months versus 10 months in pediatric patients (p = 0.002). No significant difference in OS between RT and CHRT was observed in pediatric or adult subgroups (p > 0.05). The use of CHRT has significantly increased over the years. In the multivariate analysis, adult patients were the only independent prognostic factor associated with a better OS (p < 0.001).

Conclusions

BSG had poor survival with no significant improvement in the treatment outcomes over the last 20 years, despite the addition of chemotherapy. Adult patients were independently associated with better survival.

Medullary brainstem gliomas in an adult: A rare case report and challenging tumor

Background

Medullary brainstem lesions are rare tumors that are challenging to treat due to their location in the brainstem, which controls vital functions such as breathing, heart rate, and blood pressure. While the most common subtype is the aggressive diffuse intrinsic pontine glioma, other subtypes exist, including focal brainstem gliomas and cervicomedullary gliomas. The prognosis for patients with brainstem gliomas is generally poor, and treatment options are limited. Early detection and treatment are crucial to improve outcomes for patients with these tumors.

Case Description

In this case report, the authors describe a 28-year-old male from Saudi Arabia who presented with headaches and vomiting. Imaging studies and clinical examination revealed a high-grade astrocytoma medullary brainstem lesion. The patient underwent radiation therapy and chemotherapy, effectively controlling tumor growth and improving his quality of life. However, a residual tumor remained, and the patient underwent neurosurgery to resect the remaining tumor was successful in removing the tumor, and the patient showed significant improvement in his symptoms and overall health.

Conclusion

This case highlights the importance of early detection and treatment of medullary brainstem lesions. While radiation therapy and chemotherapy are primary treatment options, neurosurgery may be necessary to resect residual tumors. In addition, cultural and social factors may need to be considered in managing these tumors in Saudi Arabia.

Neuropsychological monitoring of cognitive function and ICF–based mental components in patients with malignant brain tumours

Background

Cognitive deficits are one of the important clinical features of patients with brain tumours, which can affect up to 30–90% of patients before treatment. The consequence is a significant and rapid degradation of the patient’s intellectual functioning, seizures, paralysis and other symptoms that prevent independent functioning. This results in a reduced quality of life and a psychological crisis not only for the patient but also for their relatives. Maintaining the patient’s function at the highest level for as long as possible is particularly important, given that long-term remission or a cure is unlikely or accompanied by significant disability.

Purpose

This paper aims to provide a narrative review to the neuropsychological procedure for monitoring cognitive function in patients with brain tumours, which may be helpful in developing adequate clinical practice and appropriate management procedures.

Methods

A narrative review was applied to search broadly across disciplines, retrieving literature from several databases (PubMed, Web of Science, and EBSCOhost).

Results

(1) discussing the methodological aspects of neuropsychological tools for monitoring cognitive function in brain tumour patients, (2) identifying the most commonly used tools and (3) their practical applicability according to the cognitive function components of the International Classification of Functioning, Disability and Health (ICF).

Conclusion

This article points to the need to systematise research tools or develop new ones, adapted to diagnostic needs with high psychometric characteristics, with particular attention to memory processes and learning effect. Rehabilitation of patients is also an important issue, which requires the use of adequate tools to assess functional disability. The International Classification of Functioning, Disability and Health (ICF) seems to be useful in this respect. The ICF has the advantage of targeting actions to improve the condition of the individual and to keep them as long as possible in a state of well-being that allows them to function effectively in society or to return to work. This is particularly important in view of the ageing population and the increasing number of diagnoses related to brain tumours.

Brainstem lesions: MRI review of standard morphological sequences

MRI signal changes in the brainstem are observed in a multitude of disorders including vascular diseases, neoplastic lesions, degenerative diseases, inflammatory disorders, metabolic diseases, infections, and trauma. In some diseases, brainstem involvement is typical and sometimes isolated, while in other diseases, brainstem lesions are only observed occasionally in the presence of other typical extra-brainstem abnormalities. In this review, we will discuss the MRI characteristics of brainstem lesions observed in different disorders associated with frequent and less frequent brainstem involvement. Identification of the origin of the brainstem lesion depends on the exact localisation of the lesion(s) inside the brainstem, the presence and the characteristics of associated lesions seen outside the brainstem, the signal changes on different MRI sequences, the evolution over time of the radiological abnormalities, the history and clinical state of the patient, and other radiological and non-radiological examinations.

Combined Treatment With Radiotherapy and Immunotherapy for Isocitrate Dehydrogenase Mutant Brainstem Glioma in Adult: A Case Report

Brainstem gliomas are not common in adults, and the treatment strategies and their outcomes are limited. Immunotherapy is emerging as a promising new modality for the treatment of these gliomas. Here, we report the first case of brainstem glioma treated with a combination of radiotherapy and autologous formalin-fixed tumor vaccine (AFTV). A 32-year-old man presented with left facial numbness and right hemiparesis, and was referred to our department. MRI and open biopsy indicated brainstem glioma, and he was specifically diagnosed with isocitrate dehydrogenase 1-mutant diffuse astrocytoma of WHO grade II. He was treated with stereotactic radiotherapy followed by AFTV three months later. MRI conducted at 42 months after the combination therapy showed a 91% decrease in tumor volume, and the regression was maintained for 5 years. Thus, combination treatment with radiotherapy and immunotherapy may prove to be a promising alternative for the treatment of brainstem glioma.

Endoscopic Endonasal Excision of a Ventral Exophytic Brainstem Glioma: A Technical Case Report

BACKGROUND AND IMPORTANCE

Ventral midbrain glioma is an extremely rare lesion in adults. The endoscopic endonasal approach is potentially a better alternative to transcranial approach for this challenging lesion and has not been described in the literature.

CLINICAL PRESENTATION

A 22-yr-old woman previously operated through an interhemispheric approach for ventral midbrain glioma with extension in the suprasellar cistern presented with severe headache and diplopia. Imaging revealed an increase in size of the residual lesion. The tumor was resected by using an extended endonasal approach. The patient had improvement in her diplopia with no endocrine complication.

CONCLUSION

This case demonstrates the surgical technique of endoscopic endonasal resection of a ventral midbrain glioma.

Fifteen-year trends and differences in mortality rates across sex, age, and race/ethnicity in patients with brainstem tumors

Background

Localization of tumors to the brainstem carries a poor prognosis, however, risk factors are poorly understood. We examined secular trends in mortality from brainstem tumors in the United States by age, sex, and race/ethnicity.

Methods

We extracted age-adjusted incidence-based mortality rates of brainstem tumors from the Surveillance, Epidemiology, and End Results (SEER) database between 2004 and 2018. Trends in age-adjusted mortality rate (AAMR) were compared by sex and race/ethnicity among the younger age group (0-14 years) and the older age group (>15 years), respectively. Average AAMRs in each 5-year age group were compared by sex.

Results

This study included 2039 brainstem tumor-related deaths between 2004 and 2018. Trends in AAMRs were constant during the study period in both age groups, with 3 times higher AAMR in the younger age group compared to the older age group. Males had a significantly higher AAMR in the older age group, while no racial differences were observed. Intriguingly, AAMRs peaked in patients 5-9 years of age (0.57 per 100 000) and in patients 80-84 years of age (0.31 per 100 000), with lower rates among middle-aged individuals. Among 5-9 years of age, the average AAMR for females was significantly higher than that of males (P = .017), whereas the reverse trend was seen among those 50-79 years of age.

Conclusions

Overall trends in AAMRs for brainstem tumors were constant during the study period with significant differences by age and sex. Identifying the biological mechanisms of demographic differences in AAMR may help understand this fatal pathology.

Prognostic factors in adult brainstem glioma: a tertiary care center analysis and review of the literature

Introduction

Adult brainstem gliomas (BSGs) are rare central nervous system tumours characterized by a highly heterogeneous clinical course. Median survival times range from 11 to 84 months. Beyond surgery, no treatment standard has been established. We investigated clinical and radiological data to assess prognostic features providing support for treatment decisions.

Methods

34 BSG patients treated between 2000 and 2019 and aged ≥ 18 years at the time of diagnosis were retrospectively identified from the databases of the two largest Austrian Neuro-Oncology centres. Clinical data including baseline characteristics, clinical disease course, applied therapies, the outcome as well as neuroradiological and neuropathological findings were gathered and analysed. The tumour apparent diffusion coefficient (ADC), volumetry of contrast-enhancing and non-contrast-enhancing lesions were determined on magnetic resonance imaging scans performed at diagnosis.

Results

The median age at diagnosis was 38.5 years (range 18–71 years). Tumour progression occurred in 26/34 (76.5%) patients after a median follow up time of 19 months (range 0.9–236.2). Median overall survival (OS) and progression-free survival (PFS) was 24.1 months (range 0.9–236.2; 95% CI 18.1–30.1) and 14.5 months (range 0.7–178.5; 95% CI 5.1–23.9), respectively. Low-performance status, high body mass index (BMI) at diagnosis and WHO grading were associated with shorter PFS and OS at univariate analysis (p < 0.05, log rank test, respectively). ADC values below the median were significantly associated with shorter OS (14.9 vs 44.2 months, p = 0.018).

Conclusion

ECOG, BMI, WHO grade and ADC values were associated with the survival prognosis of BSG patients and should be included in the prognostic assessment.

Adult brainstem glioma presenting with isolated persistent hemifacial spasm or facial nerve palsy

OBJECT

Adult brainstem gliomas are a rare group of heterogeneous brain tumors. Classical clinical presentation includes progressive impairment of cranial nerves associated with long tract signs. The prognosis and response to treatment are poor; nevertheless, some patients do have a long survival. The objective of this study was to describe a series of patients with an isolated persistent hemifacial spasm and/or facial nerve palsy as the presenting symptom of a brainstem glioma.

METHODS

Fourteen patients from 3 French hospitals (Paris, Caen, Lille) were included. Clinical and radiological features and overall survival were retrospectively analyzed. A review of the literature of similar cases was performed.

RESULTS

Mean age at diagnosis was 35 years (range 19-57 years). Mean duration of facial nerve involvement before diagnosis was 17 months (range 1-48 months). Tumors were characterized on MRI by a lateralized location in the pons, a T1-weighted hyposignal, a T2-weighted hypersignal and no contrast enhancement after Gadolinium injection except for 2 cases. Biopsies were performed in 10 cases and showed 8 low-grade and 2 high-grade gliomas. All the patients were initially treated with radiotherapy and 6 patients with chemotherapy after progression. Eleven patients died from tumor progression. Median survival time was 90 months.

CONCLUSIONS

Adult brainstem gliomas revealed by a progressive isolated involvement of the facial nerve seem to have particular clinico-radiological features of slow progressive tumors and may be associated with long patient survival.

Stereotactic posterior midline approach under direct microscopic view for biopsy of medulla oblongata tumors: technical considerations

Background

Open and stereotactic transfrontal or transcerebellar approaches have been used to biopsy brainstem lesions.

Method

In this report, a stereotactic posterior and midline approach to the distal medulla oblongata under microscopic view is described. The potential advantages and limitations are discussed, especially bilateral damage of the X nerve nuclei.

Conclusion

This approach should be considered for biopsy of distal and posterior lesions. We strongly recommend the use of direct microscopic view to identify the medullary vessels, confirm the midline entry point, and avoid potential shift of the medulla. Further experience is needed to confirm safety and success rate of this approach.

Electronic supplementary material

The online version of this article (10.1007/s00701-020-04600-6) contains supplementary material, which is available to authorized users.

Stereotactic biopsies of brainstem lesions: which approach?

BACKGROUND

Stereotactic biopsies for brainstem lesions are frequently performed to yield an accurate diagnosis and help guide subsequent management. In this study, we summarize our experience with different stereotactic approaches to brainstem lesions of different locations and discuss possible implications for safety and diagnostic yield.

METHODS

We retrospectively analyzed 23 adult patients who underwent a stereotactic biopsy for brainstem lesions between October 2011 and December 2019. Depending on the location supra- or infratentorial, trajectories were planned. We assessed the postoperative complications during the hospital stay as well as the diagnostic yield.

RESULTS

A supratentorial transfrontal approach was used in 16 (70%) cases, predominantly for lesions in the midbrain, upper pons, and medulla oblongata. An infratentorial, transcerebellar-transpeduncular approach was used in 7 (30%) cases mainly for lesions within the lower pons. All biopsies were confirmed to represent pathological tissue and a definitive diagnosis was achieved in 21 cases (91%). Three patients (13%) had transient weakness in the contralateral part of the body in the immediate postoperative period, which improved spontaneously. There was no permanent morbidity or mortality in this series of patients.

CONCLUSION

Lesions of various locations within the brainstem can be successfully targeted via either a supratentorial transfrontal or an infratentorial transcerebellar transpeduncular approach. Our high diagnostic yield of over 90% and the low rate of complications underlines the diagnostic importance of this procedure in order to guide the medical management of these patients.

Surgical considerations for maximal safe resection of exophytic brainstem glioma in the pediatric age group

Background:

Brainstem glioma is the leading cause of morbidity and mortality among all central nervous system tumors, especially in childhood as it represents about 20% of all pediatric brain tumors. Therefore, this study aimed to present our experience in a tertiary center in a developing country with limited resources for the surgical management of exophytic brainstem gliomas.

Methods:

This retrospective study included pediatric patients with brainstem (midbrain, pontine, or medullary) focal or diffuse gliomas whether low or high grade that had dorsal, ventral, or lateral exophytic component who were presented to our hospitals from January 2019 to January 2021. The patients’ data were collected, such as age, sex, preoperative and postoperative clinical condition, radiological data, surgical approach, extent of tumor removal, histopathology, follow-up period, and adjuvant therapy.

Results:

A total of 23 patients were included in this study. The telovelar approach was used in 17 patients, the supracerebellar infratentorial approach in three patients, and the retrosigmoid, transcerebellar, and occipital transtentorial approach once for each patient. Twenty patients underwent near-total excision, and three underwent subtotal excision. Two-thirds of our cases (17 patients) were low-grade gliomas, with the remaining one-third comprising entirely of either anaplastic astrocytoma (five patients) or glioblastoma multiforme (one patient). The follow-up period of the patients extended from 3 months to 24 months.

Conclusion:

Exophytic brainstem glioma surgery can result in good outcomes with minimal complications when near-total excision is attempted through a properly chosen approach and adherence to some surgical techniques and considerations.

Epidemiology of brainstem high-grade gliomas in children and adolescents in the United States, 2000-2017

BACKGROUND

Limited population-based data exist for the brainstem gliomas for children ages ≤19 years, which includes high-grade aggressively growing tumors such as diffuse intrinsic pontine glioma (DIPG). We examined the overall incidence and survival patterns in children with brainstem high-grade glioma (HGG) by age, sex, and race and ethnicity.

METHODS

We used data from Central Brain Tumor Registry of the United States (CBTRUS), obtained through data use agreements with the Centers for Disease Control (CDC) and the National Cancer Institute (NCI) from 2000 to 2017, and survival data from the CDCs National Program of Cancer Registries (NPCR), from 2001 to 2016 for malignant brainstem HGG for ages ≤19 years (per WHO ICD-O-3 codes). HGG was determined by established histologic and/or imaging criteria. Age-adjusted incidence rates and survival data were used to assess differences overall and by age, sex race, and ethnicity.

RESULTS

The incidence of brainstem HGG was higher among the female and Non-Hispanic population. Majority (69.8%) of these tumors were diagnosed radiographically. Incidence was higher in children aged 1-9 years compared to older children. Whites had a higher incidence compared to Blacks. However, the risk of death was higher among Blacks and Other race compared to Whites. There was no difference in survival by sex.

CONCLUSIONS

We report the most comprehensive incidence and survival data on these lethal brainstem HGGs. Incidence and survival among patients with brainstem HGGs differed significantly by race, ethnicity, age-groups, and grade.

Adult isocitrate dehydrogenase-mutant brainstem glioma: illustrative case

BACKGROUND

Adult brainstem gliomas are rare entities that demonstrate heterogeneous biology and appear to be distinct from both their pediatric counterparts and adult supratentorial gliomas. Although the role of histone 3 mutations is being increasingly understood in this disease, the effect of isocitrate dehydrogenase (IDH) mutations remains unclear, largely because of limited data.

OBSERVATIONS

The authors present the case of a 29-year-old male with an IDH1-mutant, World Health Organization grade III anaplastic astrocytoma in the dorsal medulla, and they provide a review of the available literature on adult IDH-mutant brainstem glioma. The authors have amassed a cohort of 15 such patients, 7 of whom have survival data available. Median survival is 56 months in this small cohort, which is similar to that for IDH wild-type adult brainstem gliomas.

LESSONS

The authors' work reenforces previous literature suggesting that the role of IDH mutation in glioma differs between brainstem and supratentorial lesions. Therefore, the authors advocate that adult brainstem gliomas be studied in terms of major molecular subgroups (including IDH mutant) because these gliomas may exhibit fundamental differences from each other, from pediatric brainstem gliomas, and from adult supratentorial gliomas.

Pilocytic Astrocytoma: A Review of General, Clinical, and Molecular Characteristics

Pilocytic astrocytomas are the primary tumors most frequently found in children and adolescents, accounting for approximately 15.6% of all brain tumors and 5.4% of all gliomas. They are mostly found in infratentorial structures such as the cerebellum and in midline cerebral structures such as the optic nerve, hypothalamus, and brain stem. The present study aimed to list the main characteristics about this tumor, to better understand the diagnosis and treatment of these patients, and was conducted on search of the published studies available in NCBI, PubMed, MEDLINE, Scielo, and Google Scholar. It was possible to define the main histologic findings observed in these cases, such as mitoses, necrosis, and Rosenthal fibers. We described the locations usually most affected by tumor development, and this was associated with the most frequent clinical features. The comparison between the molecular diagnostic methods showed great use of fluorescent in situ hybridization, polymerase chain reaction (PCR), and reverse transcriptase-PCR, important techniques for the detection of BRAF V600E mutation and BRAF-KIAA1549 fusion, characteristic molecular alterations in pilocytic astrocytomas.

Surgical treatment and prognosis of focal brainstem gliomas in children: A 7 year single center experience

This study aims to describe the role of open surgical treatment for focal brainstem gliomas (FBSGs) with the assistance of multimodal neuronavigation and intraoperative neurophysiological monitoring (IOM) in children to investigate the efficacy of microsurgical treatment in pediatric FBSGs. Also the prognostic factors related to the overall survival (OS) of FBSGs to describe the patient and tumor characteristics relevant to prognosis/outcome were focused on. Clinical data of 63 pediatric patients below 16 years of age with FBSGs admitted to the Neurosurgical Unit of Beijing Tiantan Hospital from January 2012 to December 2018 were retrospectively analyzed. All patients underwent initial surgical treatment, followed by magnetic resonance diffusion tensor imaging (DTI), neuronavigation and IOM. Gross or near total resection (GTR or NTR) was achieved in 57/63 (90.5%) cases, and subtotal resection (STR) was achieved in 6/63 (9.5%) cases. Postoperative adjuvant therapy was received by 27/63 (42.9%) cases. Postoperative pathological examination revealed that 36/63 (57.1%) cases had grade I gliomas, 22/63 (34.9%) had grade II, and 5/63 (8.0%) had grade III-IV gliomas according to the WHO classification. The mean Karnofsky score preoperatively was 60, and at the time of follow-up was 90. Consecutively, 6 cases demonstrated disease progression, and 5 of these were deceased. The OS in all patients was 81.2% at 5 years. Histological grade (P < .001) and age at diagnosis (P = .023) showed significant association with prolonged OS. Multimodal neuronavigation and IOM allow very precise intracranial surgery, contributing to a maximally safe resection that might decrease the postoperative disability and mortality rate. This study also showed that pediatric FBSGs were mostly low-grade tumors with excellent surgical outcomes. Consequently, it is suggested that microsurgery can be used to treat FBSGs in children in order to provide better prognosis and survival outcomes.

Cavernous Sinus Dural Arteriovenous Fistula with an Enhanced Lesion in the Brainstem Mimicking a Malignant Tumor

BACKGROUND

Cavernous sinus (CS) dural arteriovenous fistula (dAVF) with an enhanced lesion in the brainstem is rare, and an enhanced lesion in the brainstem might be indicative of irreversibility.

CASE DESCRIPTION

A 77-year-old woman presented with double vision and ataxia. Magnetic resonance imaging showed a unilateral enhancement lesion in the pons, so a malignant brain tumor was suspected. A cerebral angiogram revealed CS-dAVF with retrograde leptomeningeal venous drainage (RLVD) to the brainstem. Transvenous embolization with selective coil embolization of RLVD was performed, and the symptoms and imaging improved dramatically.

CONCLUSIONS

DAVFs with RLVD should be mentioned as a differential diagnosis of enhanced lesions in the brainstem. Transvenous embolization with selective coil embolization of RLVD was effective for the treatment of CS-dAVF, and a unilateral enhanced brainstem lesion may be reversible.

Investigating dynamic susceptibility contrast-enhanced perfusion-weighted magnetic resonance imaging in posterior fossa tumors: differences and similarities with supratentorial tumors

PURPOSE

To assess the accuracy of dynamic susceptibility contrast-enhanced perfusion-weighted magnetic resonance imaging in glioma grading and brain tumor characterization of infratentorial tumors, and to investigate differences from supratentorial tumors.

METHODS

This retrospective study, approved by the institutional review board, included 246 patients with brain tumors (184 supratentorial, 62 infratentorial), grouped by tumor type: high-grade gliomas (HGG), low-grade gliomas (LGG), metastases (Met), and primary central nervous system lymphoma (PCNSL). Relative cerebral blood volume (rCBV) and mean percentage of signal recovery (PSR) were calculated. For statistical analyses, lesions were grouped by location and histology. Differences were tested with Mann-Whitney U tests. From ROC curves, we calculated accuracy, sensitivity, specificity, PPV, and NPV, for rCBV and PSR.

RESULTS

For infratentorial tumors, rCBV was highly accurate in differentiating HGG from LGG (AUC = 0.938). Mean PSR showed high accuracy in differentiating PCNSL and HGG from Met (AUC = 0.978 and AUC = 0.881, respectively). Infratentorial and supratentorial tumors had similarly high rCBV in HGG, high mean PSR in PCNSL, and low mean PSR in Met. The main differences were the optimum threshold rCBV values (3.04 for supratentorial, 1.77 for infratentorial tumors) and the mean PSR, which was significantly higher in LGG than in HGG in supratentorial (p = 0.035), but not infratentorial gliomas. Using infratentorial rCBV threshold values for supratentorial tumors decreased the sensitivity and specificity.

CONCLUSION

rCBV and mean PSR were useful in grading and differentiating infratentorial tumors. Proper cutoff values were important in the accuracy of perfusion-weighted imaging in posterior fossa tumors.

The role of radiation and chemotherapy in adult patients with high-grade brainstem gliomas: results from the National Cancer Database

INTRODUCTION

Surgical resection of high-grade brainstem gliomas is challenging and treatment mostly involves radiation and chemotherapy. In this study, we utilized registry data to determine prognostic features and impact of chemotherapy and radiation on overall survival.

METHODS

The National Cancer Database was queried from 2006 to 2015 for adult cases with histologically confirmed high-grade brainstem glioma. Covariates including patient demographics, comorbidities, tumor characteristics and treatment parameters were captured. Multivariable Cox proportional hazards regression was performed to identify predictors of survival.

RESULTS

A total of 422 patients were analyzed. Most patients (66.6%) underwent postoperative radiation with chemotherapy, 9.2% underwent radiation alone, while the remaining had no postoperative treatment (24.2%). Overall median survival was 9.8 months (95% CI 8.8-12). Survival was longer (p < 0.001) in the radiation + chemotherapy group (median: 14.2 months, 95% CI 11.7-17.1) compared to radiation alone (median: 5.7 months, 95% CI 3.7-12) and no postoperative treatment (median: 1.8 months, 95% CI 1.4-4) groups. In multivariable analysis, increasing age was associated with worse survival (HR: 1.87, 95% CI 1.47-2.37, p < 0.001), whereas radiation + chemotherapy was associated with lower mortality compared to radiation alone (HR: 0.67, 95% CI 0.46-0.98, p = 0.038). In subgroup analysis, postoperative chemotherapy with radiation was associated with significant survival benefit compared to radiation alone for grade IV (HR: 0.46, 95% CI 0.28-0.76, p = 0.003), but not for grade III tumors (HR: 0.87, 95% CI 0.48-1.58, p = 0.65).

CONCLUSION

Analysis from a national registry illustrated the effectiveness of radiation with chemotherapy for adult patients with high-grade brainstem gliomas, particularly grade IV. Further research should identify specific patient profiles and molecular subgroups that are more likely to benefit from multimodality therapy.

Association between extent of resection on survival in adult brainstem high-grade glioma patients

BACKGROUND

Brainstem high-grade gliomas (HGG) are rare lesions with aggressive behavior that pose significant treatment challenges. The operative use of brainstem safe entry zones has made such lesions surgically accessible, though the benefits of aggressive resection have been unclear. This study aimed to clarify the survival in adult patients.

METHODS

We utilized the SEER database (1973-2015) to analyze the association between survival and demographic data, tumor characteristics, and treatment factors in adult patients with brainstem HGGs. Patients without surgical intervention were excluded. Overall survival (OS) was analyzed using univariable and multivariable Cox regression.

RESULTS

Our dataset included a total of 502 brainstem HGG patients of which only those who had undergone surgical intervention were included in the analysis, totaling 103. Mean age was 42.4 ± 14.1 years with 57.2% (n = 59) male. Median OS of the entire cohort was 11.0 months. Median OS for patients receiving biopsy, subtotal resection, and gross total resection were 8, 11, and 16 months, respectively. Age, extent of resection, and radiation therapy were selected into the multivariable model. A significant decrease in survival was seen in older patients, 50-60 years (HR = 2.77, p = 0.002) and ≥ 60 years (HR = 5.30, p < 0.001), compared to younger patients (18-30 years). Partial resection (HR = 0.32, p = 0.006) and GTR (HR = 0.24, p < 0.001) sustained survival benefits compared to patients with biopsy only. Patients receiving postoperative radiation demonstrated no survival benefit (HR = 1.57, p = 0.161) in multivariable regression.

CONCLUSIONS

While survival of brainstem HGG patients remains poor, for surgically accessible HGGs, STR and GTR were associated with a three and fourfold increase in overall survival when compared to biopsy only.

Partnership for defining the impact of 12 selected rare CNS tumors: a report from the CBTRUS and the NCI-CONNECT

PURPOSE

Population-based cancer statistics, including histology-specific incidence, prevalence, and survival are essential to evaluating the total burden due to disease in a population. The National Cancer Institute's (NCI) Comprehensive Oncology Network Evaluating Rare CNS Tumors (NCI-CONNECT) was developed to better understand tumor biology and patient outcomes for 12 selected brain and other central nervous system (CNS) tumor histologies that are rare in adults to improve approaches to care and treatment. The aim of this study was to determine the incidence, prevalence, and survival of these selected rare histologies.

METHODS

Data from the Central Brain Tumor Registry of the United States (CBTRUS) from 2000 to 2014 were used to calculate average annual age-adjusted incidence rates (AAIR) per 100,000 population overall and by sex, race, ethnicity, and age. NCI's Surveillance, Epidemiology and End Results (SEER) data were used to calculate relative survival (RS) estimates. Point prevalence for 2014 was estimated using annual age-specific incidence and survival from CBTRUS and SEER, respectively.

RESULTS

Overall AAIR was 1.47 per 100,000 for all 12 rare histologies combined, with the highest histology-specific incidence in oligodendrogliomas (AAIR = 0.40/100,000). Overall, most histologies were more common in males, adults (age 40 + ), Whites, and non-Hispanics. Ependymomas were the most prevalent histology at 4.11 per 100,000; followed by oligodendrogliomas at 3.68 per 100,000. Relative survival at 1-, 5-, and 10-years was 82.3%, 64.0%, and 55.4%, respectively for all 12 selected brain and other CNS tumor types combined. Ependymomas had the highest RS (1-year = 94.2%, 5-year = 83.9%, 10-year = 78.6%) and gliosarcomas had the lowest relative survival rate (1-year = 42.5%, 5-year = 5.6%, 10-year = 2.9%) at all three time points.

CONCLUSIONS

Incidence and prevalence of these rare brain and other CNS tumor histologies have not been previously reported. Along with survival, these data provide a statistical foundation to understand the impact of these cancers and provide important disease-specific data for the design of prospective clinical trials.

Rescue bevacizumab following symptomatic pseudoprogression of a tectal glioma post-radiotherapy: a case report and review of the literature

PURPOSE

Radiation-induced pseudoprogression is a subacute clinical entity that is distinct from radiation necrosis and mimics tumor progression. Bevacizumab is a well-described treatment option for radiation necrosis, but its role in pseudoprogression is not clearly defined.

METHODS

We report a case of radiation-induced pseudoprogression rescued with bevacizumab in a 20-year-old man with a biopsy-proven low-grade astrocytoma of the tectum. A review of the literature was also conducted specific to bevacizumab as a treatment for symptomatic pseudoprogression after radiotherapy for CNS tumors.

RESULTS

This patient was treated with definitive intensity modulated stereotactic radiotherapy at a total dose of 54 Gy delivered in 30 daily fractions. Six weeks after radiotherapy the patient developed progressive headache, weakness and a documented deterioration in vision, which was accompanied by worsening of radiographic findings. A diagnosis of pseudoprogression was made and after limited benefit from a trial of dexamethasone, four cycles of bevacizumab were administered which resulted in rapid clinical and radiographic improvement.

CONCLUSIONS

Our findings support the potential use of bevacizumab as a rescue agent for symptomatic pseudoprogression.

Clinical Efficacy of CyberKnife Radiosurgery for Adult Brainstem Glioma: 10 Years Experience at Tianjin CyberKnife Center and Review of the Literature

Background: Brainstem glioma is a rare brain tumor with poor prognosis and difficulty for surgical resection. We sought to retrospectively analyze and evaluate the clinical efficacy of CyberKnife for brainstem gliomas.

Methods: From 2006 to 2015, a total of 21 brainstem gliomas patients who received CyberKnife radiosurgery treatment enrolled in this study and 18 patients with follow up. CyberKnife image-guided radiosurgical system were applied consecutively with the median prescribed total dose of 26 Gy (14–33 Gy) at two to six fractions on days utilizing CyberKnife system, and the median biological equivalent doses of 59.8 Gy (33.6–76.56 Gy). The clinic pathlogical features, survival were analyzed to explore the efficacy of CyberKnife radiosurgery in treatment of brainstem glioma.

Results: With median follow-up of 54.5 months, patients with brainstem gliomas had median overall survival of 19 months, five patients still alive. The primary endpoints of the 1- and 2-year overall survival rates were 87.5 and 52.4%, respectively. During the treatment course, six patients were observed to have pseudoprogression with mass effect on MRI. Four patients developed radiation complications. Grade 2 radiation-related toxicity were observed in three patients and one patient with grade 3.

Conclusion: The efficacy of brainstem gliomas—treated with CyberKnife is efficacious with mild toxicity.

Evidence-Based Practice: Temozolomide Beyond Glioblastoma

PURPOSE OF REVIEW

Temozolomide is a first-line treatment for newly diagnosed glioblastoma. In this review, we will examine the use of temozolomide in other contexts for treating gliomas, including recurrent glioblastoma, glioblastoma in the elderly, diffuse low- and high-grade gliomas, non-diffuse gliomas, diffuse intrinsic pontine glioma (DIPG), ependymoma, pilocytic astrocytoma, and pleomorphic xanthoastrocytoma.

RECENT FINDINGS

Temozolomide improved survival in older patients with glioblastoma, anaplastic gliomas regardless of 1p/19q deletion status, and progressive ependymomas. Temozolomide afforded less toxicity and comparable efficacy to radiation in high-risk low-grade gliomas and to platinum-based chemotherapy in pediatric high-grade gliomas. The success of temozolomide in promoting survival has expanded beyond glioblastoma to benefit patients with non-glioblastoma tumors. Identifying practical biomarkers for predicting temozolomide susceptibility, and establishing complementary agents for chemosensitizing tumors to temozolomide, will be key next steps for future success.

Treatment of adult brainstem glioma with combined antiangiogenic therapy: a case report and literature review

Adult brainstem gliomas belong to a rare and heterogeneous group of brain tumors. The overall prognosis is poor; therapeutic options are limited, given the resistance to radiotherapy and the unclear role of chemotherapy/antiangiogenic therapy. Apatinib, a tyrosine kinase inhibitor that selectively inhibits the vascular endothelial growth factor receptor and mildly inhibits c-Kit, PDGFR-β, RET, and c-SRC, has been reported to show efficacy among some patients with malignant supratentorial gliomas. However, its effect on brainstem glioma has not been reported so far. Herein, a 66-year-old man with brainstem anaplastic astrocytoma isocitrate dehydrogenase (IDH) wild type was treated initially with combined radiotherapy, temozolomide, and apatinib. The patient achieved a complete response by MRI and continues to have an ongoing progression-free survival of over 8 months. To our knowledge, this is the first case report using apatinib to treat brainstem IDH wild-type anaplastic astrocytoma, displaying an excellent outcome. We also summarize cases of adult brainstem glioma treated with antiangiogenic therapy. Experiences using various regimens may improve understanding of this rare disease, and thus help physicians to seek more effective treatments for these patients.

Brainstem gliomas in pregnancy: a systematic review†

Introduction: Although brainstem gliomas are a rare group of neoplasias, when they affect pregnant women, there can be challenges with diagnosis and management. This study describes a case of brainstem glioma diagnosed in pregnancy and systematically reviews the literature on brainstem gliomas in pregnancy to provide guidance for management.Material and methods: We searched five databases from inception until October 2016 using subject headings and keywords related to pregnancy and brainstem glioma, and included original research articles that described pregnancy outcomes in women with brainstem glioma. Data extraction and quality assessment using the Joanna Briggs Institute Critical Appraisal Checklist for case reports were performed in duplicate. Outcomes were reported as proportions. The study protocol was registered with the Prospero International Prospective Register of Systematic Reviews (CRD42017060196).Results: We screened 2737 titles and abstracts, and 89 full-texts. Twelve articles describing 17 pregnancies in 16 women were included in the analysis. The median gestational age at presentation was 23 weeks. All but one case presented with neurologic deficit. Magnetic resonance (MRI) imaging conclusively diagnosed all cases. Surgical tumor resection (n = 4) and radiation therapy (n = 3) were successfully undertaken during pregnancy. There were no reported sequelae of maternal oncological management on neonatal wellbeing. Maternal mortality was high (8/16, 50%) both during (n = 5) and within 4 weeks (n = 3) of pregnancy. Pregnancy losses included one pregnancy termination and four miscarriages (associated with maternal mortality). Of the 12 live-born babies, five were premature. Two of these were the result of spontaneous preterm labor and three were delivered prematurely to facilitate glioma management. There was one case of fetal growth restriction.Conclusions: Although the symptoms of brainstem gliomas often mimic those commonly encountered in pregnancy, neurologic deficits warrant urgent investigation. MRI is the diagnostic modality of choice in pregnancy. Brainstem gliomas are associated with high maternal mortality and appropriate management, including surgical tumor resection and radiation therapy, should not be delayed on account of pregnancy. Pregnancy outcomes are favorable although there is a risk of preterm birth.Key messageBrainstem gliomas are associated with high maternal mortality and timely diagnosis using magnetic resonance imaging and treatment including surgical resection and radiation therapy should not be delayed during pregnancy. Pregnancy outcomes are generally favorable except for risk of preterm birth.

Optimal extent of resection for glioblastoma according to site, extension, and size: a population-based study in the temozolomide era

The effect of the extent of resection (EOR) on prognosis in glioblastoma may differ depending on various conditions. We evaluated the prognostic impact of the EOR for glioblastoma according to the tumor site, extension, and size. Data from glioblastoma patients who underwent gross total resection (GTR), subtotal resection (STR), or open biopsy between 2005 and 2014 were retrieved from the Surveillance, Epidemiology, and End Results database. Univariate and multivariate analyses for overall survival (OS) were performed. Between 2005-2009 and 2010-2014, the proportion of GTR and STR performed increased from 41.4 to 42.3% and 33.0 to 37.1%, respectively. EOR only affected OS in the 3 years after diagnosis. Median survival in the GTR (n = 4155), STR (n = 3498), and open biopsy (n = 2258) groups was 17, 13, and 13 months, respectively (p < .001). STR showed no significant difference in OS from open biopsy (p = .33). GTR increased OS for midline-crossing tumors. Although STR was more frequently performed than GTR for tumors ≥ 6 cm in size, GTR significantly increased the OS rate relative to STR for tumors 6-8 cm in size (p = .001). For tumors ≥ 8 cm, STR was comparable to GTR (p = .61) and superior to open biopsy (p = .05). GTR needs to be performed more frequently for glioblastoma measuring ≥ 6 cm or that have crossed the midline to increase OS. STR was marginally superior to open biopsy when the tumor was ≥ 8 cm.

Brainstem astrocytoma as a neuro-Behçet's disease mimic

A 58-year-old man with a history of recurrent aphthous ulcers since childhood was admitted to the hospital with acute neurological decline characterised by loss of motor dexterity, dysarthria, dysphagia and unsteady gait. MRI brain was significant for symmetrical hyperintense T2 fluid attenuated inversion recovery (FLAIR) in the corticospinal tracts, including parts of the pons and the mesodiencephalic junction. Though initial concern was for neuro-Behçet's disease, brain biopsy ultimately revealed a diagnosis of astrocytoma. This report demonstrates a mimic of neuro-Behçet's disease and the importance of confirming the correct diagnosis prior to initiating therapy.

Surgical treatment and prognosis of adult patients with brainstem gliomas

The paper presents 47 adult patients who were surgically treated due to brainstem gliomas. Thirteen patients presented with contrast-enhancing Grades III and IV gliomas, according to the WHO classification, 13 patients with contrast-enhancing tumours originating from the glial cells (Grade I; WHO classification), 9 patients with diffuse gliomas, 5 patients with tectal brainstem gliomas and 7 patients with exophytic brainstem gliomas. During the surgical procedure, neuronavigation and the diffusion tensor tractography (DTI) of the corticospinal tract were used with the examination of motor evoked potentials (MEPs) and somatosensory evoked potentials (SSEPs) with direct stimulation of the fundus of the fourth brain ventricle in order to define the localization of the nuclei of nerves VII, IX, X and XII. Cerebellar dysfunction, damage to cranial nerves and dysphagia were the most frequent postoperative sequelae which were also the most difficult to resolve. The Karnofsky score established preoperatively and the extent of tumour resection were the factors affecting the prognosis. The mean time of progression-free survival (14 months) and the mean survival time after surgery (20 months) were the shortest for malignant brainstem gliomas. In the group with tectal brainstem gliomas, no cases of progression were found and none of the patients died during the follow-up. Some patients were professionally active. Partial resection of diffuse brainstem gliomas did not prolong the mean survival above 5 years. However, some patients survived over 5 years in good condition.

FGFR1 actionable mutations, molecular specificities, and outcome of adult midline gliomas

OBJECTIVE

To characterize the prevalence and prognostic significance of major driver molecular alterations in adult midline diffuse gliomas (MLG).

METHODS

Adults with histologically proven MLG diagnosed between 1996 and 2017 were identified from our tumor bank, systematically reviewed, and reclassified according to WHO 2016. Targeted sequencing was performed, including determination of H3F3A, HIST1H3B, TERTp, IDH1/2, FGFR1, p16/CDKN2A, and EGFR status.

RESULTS

A total of 116 adult patients (M/F 71/45, median age 46.5 years) with MLG (17 cerebellar, 8 spinal, 30 brainstem, 57 thalamic, and 4 diencephalic nonthalamic) were identified. Most patients had high-grade disease at presentation (grade II: 11%, grade III: 15%, grade IV: 75%). Median overall survival was 17.3 months (14.5-23.8 months). Main molecular alterations observed were TERT promoter, H3F3A, and hotspot FGFR1 (N546 and K656) mutations, in 37%, 34%, and 18% of patients, respectively. IDH1 mutations only affected brainstem gliomas (6/24 vs 0/78; p = 7.5 × 10^-5), were mostly non-R132H (contrasting with hemispheric gliomas, p = 0.0001), and were associated with longer survival (54 vs 12 months). TERT promoter mutation (9.1 vs 24.2 months), CDKN2A deletion (9.9 vs 23.8 months), and EGFR amplification (4.3 vs 23.8 months) were associated with shorter survival. Of interest, in contrast with pediatric MLG, H3K27M mutations were not associated with worse prognosis (23 vs 15 months).

CONCLUSIONS

Patients with adult MLG present with unique clinical and molecular characteristics, differing from their pediatric counterparts. The identification of potentially actionable FGFR1 mutations in a subset of adult MLG highlights the importance of comprehensive genomic analysis in this rare affection.

Closed Stereotactic Needle Biopsy of Brainstem Small Cell Glioblastoma: A Case Report and Literature Review

Glioblastoma is the deadliest and most common of the malignant primary brain tumors that can occur in adults. In contrast, brainstem gliomas are extremely uncommon in adults; however, their precise incidence is not known, due to the difficult nature of obtaining tissue from the brainstem provoking low biopsy and resection rates. In this case report, we have examined a 34-year-old female who was diagnosed with pontomedullary small cell glioblastoma following a successful biopsy of the brainstem lesion. A closed stereotactic needle biopsy with a contralateral approach was utilized using stealth computed tomography (CT) neuronavigation for tissue diagnosis without causing additional neurological deficits. Our goal is to share this novel approach of obtaining tissue from the brainstem in order to aid others in definitively diagnosing brainstem gliomas and subsequently providing appropriate treatment early in the disease process.

Endoscopic Endonasal Transclival Approach for Resection of a Pontine Glioma: Surgical Planning, Surgical Anatomy, and Technique

BACKGROUND

The endoscopic endonasal approach (EEA) has been proposed as a potential alternative for ventral brainstem lesions. The surgical anatomy, feasibility, and limitations of the EEA for intrinsic brainstem lesions are still poorly understood.

OBJECTIVE

To describe the surgical planning, anatomy, and technique of an intrinsic pontine glioma operated via EEA.

METHODS

Six-human brainstems were prepared for white matter microdissection. Ten healthy subjects were studied with high-definition fiber tractography (HDFT). A 56-yr-old female with right-hemiparesis underwent EEA for an exophytic pontine glioma. Pre- and postoperative HDFTs were implemented.

RESULTS

The corticospinal tracts (CSTs) are the most eloquent fibers in the ventral brainstem. At the pons, CSTs run between the pontine nuclei and the middle cerebellar peduncle (MCP). At the lower medulla, the pyramidal decussation leaves no room for safe ventral access. In our illustrative case, preoperative HDFT showed left-CST displaced posteromedially and partially disrupted, right-CST posteriorly displaced, and MCP severely disrupted. A transclival exposure was performed achieving a complete resection of the exophytic component with residual intra-axial tumor. Immediately postop, patient developed new left-side abducens nerve palsy and worse right-hemiparesis. Ten days postop, her strength returned to baseline. HDFT showed preservation and trajectory restoration of the CSTs.

CONCLUSION

The EEA provides direct access to the ventral brainstem, overcoming the limitations of lateral approaches. For intrinsic pathology, HDFT helps choosing the most appropriate surgical route/boundaries for safer resection. Further experience is needed to determine the indications and limitations of this approach that should be performed by neurosurgeons with high-level expertise in EEA.

Brainstem glioma: Prediction of histopathologic grade based on conventional MR imaging

Objective The objective of this article is to investigate the association between specific MR imaging findings and histopathologic grading (low-grade vs. high-grade) of brainstem gliomas (BSGs). Methods Sixty-two males and 34 females (mean (standard deviation, SD) age of 24.61 (17.20) years, range = 3 to 70 years) with histologically diagnosed BSG underwent conventional 1.5 T MR imaging, which included T1-weighted (T1W), T2W, and post-contrast T1W sequences. There were 39 children (mean age of 9.38 years) and 57 adults (mean age of 35 years). A binary logistic regression analysis was used to explore associations between MRI features and histopathological grade of the BSG. Results Binary logistic regression revealed that necrosis (adjusted odds ratio (OR) = 16.07; 95% confidence interval (CI) = 3.20 to 80.52; p = 0.001) and inhomogeneous contrast enhancement (adjusted OR = 8.04; 95% CI = 1.73 to 37.41; p = 0.008) as significant predictors of high-grade BSG. The equation (Nagelkerke R²= 0.575) is Logit ( p high-grade BSG) = (2.77 × necrosis) + (2.08 × heterogeneous contrast enhancement) - 3.13. Sensitivity and specificity values were respectively 66.7% and 96.0% for necrosis and 85.7% and 65.9% for inhomogeneous contrast-enhancing lesions. In the pediatric age group, only inhomogeneous contrast enhancement (adjusted OR = 40; 95% CI = 3.95 to 445.73; p = 0.002) was a significant predictor for high-grade BSG. Conclusion Conventional MR imaging features such as necrosis and inhomogeneous contrast enhancement in adults and heterogeneous contrast enhancement in children suggest high-grade BSG.

Rotating Gamma System Irradiation: A Promising Treatment for Low-grade Brainstem Gliomas

AIM

To evaluate the role of rotating gamma system (RGS) radiosurgery for low-grade brainstem gliomas.

PATIENTS AND METHODS

Thirty-seven patients undergoing RGS radiosurgery at the Bach Mai Hospital Hanoi for low-grade brainstem glioma were included in this prospective interventional study. The median RGS dose was 12 Gy (range=8-16 Gy). Endpoints included response to RGS radiosurgery given as change in glioma size (maximum diameter), survival and adverse events. Follow-up was performed for 36 months. Three dose-groups (<13, 13-14 and >14 Gy) were compared for survival.

RESULTS

Mean glioma size decreased from 1.87 cm before RGS irradiation to 1.15 cm at 36 months. Mean survival was 39.5 months. Mean survival after <13, 13-14 and >14 Gy were 22.7, 66.7 and 49 months, respectively (p<0.05). Adverse events, mainly reduced appetite, sleep disturbances, headache and edema, were not associated with RGS dose and were easily managed.

CONCLUSION

RGS radiosurgery led to promising results with acceptable toxicity in patients with low-grade brainstem gliomas.

Genetic and immune features of resectable malignant brainstem gliomas

We surveyed common genetic mutations (IDH1, H3F3A, PPM1D, and TP53) and immune features (PD-L1 expression and CD8⁺ T cell tumor infiltration) in a series of 62 malignant brainstem gliomas that were resected via microsurgery. IDH1 mutations were mutually exclusive with H3F3A mutations. IDH1 mutations appeared only in adults and occurred more frequently in tumors larger than 10cm³ (8/29 vs 1/32, Fisher’s exact test, p=0.010). H3F3A mutations occurred more frequently in children and adolescent patients (19/24 vs 18/38, chi-square test, p=0.013), low preoperative Karnofsky Performance Scale (KPS) patients (10/11 vs 20/43, chi-square test, p=0.021), and higher grade brainstem gliomas (8/21 in grade II vs 16/24 in grade III vs 13/17 in grade IV; chi-square test, p=0.038). PPM1D mutations clustered in H3F3A-mutated tumors (12/37), whereas were rare in H3F3A wildtype tumors (1/25). MGMT promoter methylations clustered in IDH1-mutated tumors (4/9), but were rare in H3F3A-mutated tumors (1/37). PD-L1 staining was detected in 59.7% of brainstem glioma specimens (37/62). High intra-tumoral CD8⁺ T cell density was less frequent in the H3F3A-mutated than H3F3A-wild-type tumors (4/37 vs. 11/25, p=0.005). Patients with H3F3A-mutated tumors (13.8 months overall survival) had much worse prognoses than those with IDH1-mutated (54.9 months, p=0.001) or H3F3A-IDH1 co-wildtype tumors (38.4 months, p=0.001). H3F3A mutations independently increased the relative risk of death as much as 4.19-fold according to a multivariate Cox regression model. Taken together, resectable malignant brainstem gliomas can be classified into three subtypes: H3F3A-mutated, IDH1 mutated and H3F3A-IDH1 co-wildtype tumors, which have distinct clinical characteristics, prognoses, genetic and immune features.

Prognostic indicators of adult medullary gliomas after microsurgical treatment - A retrospective analysis of 54 patients

Due to the low incidence of medullary gliomas, the special location, and the function of the gliomas in the medulla oblongata, microsurgical treatment is still challenging for neurosurgeons. The aim of this study was to observe the effect of microsurgical treatment of adult medullary gliomas and to explore the prognostic factors after treatment. The clinical data from 54 patients with adult medullary gliomas who received microsurgical treatment at Beijing Tiantan Hospital (China) from April 2008 to April 2014 was retrospectively analyzed. The factors affecting their prognosis were analyzed with log-rank univariate analysis. The factors that affected prognosis included age, gender, duration of preoperative symptoms, Karnofsky Performance Scale (KPS) score, World Health Organization (WHO) grade, extent of tumor resection, and postoperative complications. Those with statistical significance in the univariate analysis were entered into a multivariate Cox regression analysis. WHO grading showed 7 cases of grade I, 30 cases of grade II, 14 cases of grade III, and 3 cases of grade IV tumors. Univariable analysis showed that postoperative nasogastric feeding (P=0.031), WHO pathological grade (P=0.018), extent of resection (P=0.016), and preoperative involvement of ≥3 cranial nerves (CNs) (P=0.014) affected overall survival. The WHO pathological grade of the tumor was an independent risk factor for prognosis. In conclusion, the WHO pathological grade of the tumor was an important prognostic indicator.

Basic Characteristics of Oligodendrogliomas at the Shohada-e Tajrish Hospital (2008 to 2014)

BACKGROUND AND OBJECTIVES

Gliomas are the most prevalent subgroup of primary brain tumors with a relatively high mortality. However, oligodendrogliomas have a better prognosis compared to other subtypes due to their sensitivity to chemotherapy. Considering the low incidence and the resulting lack of information about oligodendrogliomas, particularly in Iran, this study aimed at assessing their basic characteristics.

METHODS

In this descriptive retrospective study, patients with definite diagnosis of oligodendroglioma were identified by reviewing the archives of pathology reports at the department of pathology of Shohada-e Tajrish Hospital during years 2008 to 2014. Age, gender, location, and the grade of the tumor were extracted and entered to the SPSS statistical software for analysis.

RESULTS

A total of 182 patients, including 115 males (63.2%) and 67 females (36.8%), were included with a mean age of 38.5±13.36 years. Frontal lobe was involved in 53 patients (29.1%), parietal lobe in 31 (17.0%), temporal lobe in 22 (12.1%), frontoparietal area in 15 (8.2%), parieto-occipital area in 11 (6.0%), temporoparietal and frontotemporal areas each in 9 subjects (4.9%), occipital lobe in 5 (2.7%), and the brainstem in 4 (2.2%). Furthermore, 108 cases (59.3%) had grade-2 and the remaining74 patients (40.7%) had grade-3 anaplastic oligodendrogliomas. The mean age of subjects with brainstem oligodendrogliomas was significantly lower than the other patients (p=0.025).

CONCLUSION

Oligodendrogliomas commonly effects the frontal lobe, followed by the parietal and temporal lobes. The mean age of subjects with brainstem lesions was significantly lower than other patients. Age, gender or location of the tumor did not independently predict a higher grade lesion.

[Brain stem glioma: a rare cause of central vertigo in adults]

Unlike children, brainstem gliomas in adults are rare and represent a heterogeneous group of tumors: often low grade tumors having a better prognosis. These tumors are a rare cause of central vertigo in adults. The treatment of diffuse gliomas is based on radiation therapy. We here report the case of a 35-year old female patient with low grade brainstem glioma revealed by balance disorders, in order to highlight the different clinical, paraclinical and radiological aspects of this disease as well as the therapeutic tools and the progressive methods.