Spinal cord high-grade infiltrating gliomas in adults: clinico-pathological and molecular evaluation

H3K27M-mutant glioma in thoracic spinal cord and conus medullaris with pilocytic astrocytoma morphology: case report and review of the literature

BACKGROUND

The H3K27M-mutant spinal cord gliomas are very aggressive with a dismal prognosis, very few cases have been reported in the thoracic spinal cord and conus medullaris, and it is extremely rare with morphological features of pilocytic astrocytoma.

CASE PRESENTATION

A 20-year-old man presented with thoracolumbar pain, progressive paraparesis, and urinary incontinence. Magnetic resonance imaging revealed an intramedullary solid-cystic lesion from D9 to conus medullaris. Subtotal resection was performed, restricted by the indistinct margins and the decline of the motor evoked potential during the surgery. Pathologic findings revealed a pilocytic astrocytoma with anaplastic features. However, a further assessment determined a diffuse midline glioma H3K27M-mutant, and adjuvant chemoradiotherapy was administered. After seven months of progression-free survival, the paraparesis worsened; at twelve months of follow-up, the patient developed paraplegia, and at 24 months the patient remains alive without any neurologic functions distal to the tumor and he is still under adjuvant treatment.

CONCLUSIONS

The H3K27M-mutant spinal cord glioma is a very infrequent tumor with a wide variety of histological presentations even as indolent as pilocytic astrocytoma, which should be considered in spinal cord tumors, especially if there are clinical, histological, or radiological data that suggest aggressiveness. On the other hand, the fast progression led to the loss of complete neurological function distal to the tumor, in spinal tumors could explain a not so poor prognosis as it is in functionally and vital structures.

Neuroradiological, genetic and clinical characteristics of histone H3 K27-mutant diffuse midline gliomas in the Kansai Molecular Diagnosis Network for CNS Tumors (Kansai Network): multicenter retrospective cohort

This study aims to elucidate the clinical and molecular characteristics, treatment outcomes and prognostic factors of patients with histone H3 K27-mutant diffuse midline glioma. We retrospectively analyzed 93 patients with diffuse midline glioma (47 thalamus, 24 brainstem, 12 spinal cord and 10 other midline locations) treated at 24 affiliated hospitals in the Kansai Molecular Diagnosis Network for CNS Tumors. Considering the term "midline" areas, which had been confused in previous reports, we classified four midline locations based on previous reports and anatomical findings. Clinical and molecular characteristics of the study cohort included: age 4-78 years, female sex (41%), lower-grade histology (56%), preoperative Karnofsky performance status (KPS) scores ≥ 80 (49%), resection (36%), adjuvant radiation plus chemotherapy (83%), temozolomide therapy (76%), bevacizumab therapy (42%), HIST1H3B p.K27M mutation (2%), TERT promoter mutation (3%), MGMT promoter methylation (9%), BRAF p.V600E mutation (1%), FGFR1 mutation (14%) and EGFR mutation (3%). Median progression-free and overall survival time was 9.9 ± 1.0 (7.9-11.9, 95% CI) and 16.6 ± 1.4 (13.9-19.3, 95% CI) months, respectively. Female sex, preoperative KPS score ≥ 80, adjuvant radiation + temozolomide and radiation ≥ 50 Gy were associated with favorable prognosis. Female sex and preoperative KPS score ≥ 80 were identified as independent good prognostic factors. This study demonstrated the current state of clinical practice for patients with diffuse midline glioma and molecular analyses of diffuse midline glioma in real-world settings. Further investigation in a larger population would contribute to better understanding of the pathology of diffuse midline glioma.

Primary Intramedullary Spinal High-Grade Glioma: A Case Series with Review of Literature

AashitaBackground  Primary intramedullary high-grade glioma (HGG) and glioblastoma of spinal cord are uncommon tumors of central nervous system. Treatment recommendations are based on current guidelines of intracranial HGG and glioblastoma multiforme (GBM). Methods  We retrospectively analyzed records of 9,686 patients who reported to our center over past 7 years. Only three cases of primary intramedullary HGG of spinal cord were found. Results  In this article, we have reported three cases of primary intramedullary HGG of spinal cord. A comparison of intracranial and intramedullary spinal HGG and review of literature is presented. Conclusion  Despite aggressive treatment using surgery, radiation, and chemotherapy, the survival rates are dismal. Emerging evidence has shown difference in biological behavior of intracranial and spinal HGG. Genetic studies to understand the biology and prospective studies are needed.

Sequencing of cerebrospinal fluid cell-free DNA facilitated early differential diagnosis of intramedullary spinal cord tumors

Pre-surgery differential diagnosis is valuable for personalized treatment planning in intramedullary spinal cord tumors. This study assessed the performance of sequencing cell-free DNA (cfDNA) in cerebrospinal fluid (CSF) for differential diagnosis of these tumors. Prospectively enrolling 45 patients with intramedullary spinal cord lesions, including diffuse midline glioma (DMG), H3K27-altered (14/45), glioblastoma (1/45), H3-wildtype-astrocytoma (10/45), ependymoma (11/45), and other lesions (9/45), CSF samples were collected via lumbar puncture (41/45), intraoperative extraction (3/45), and Ommaya reservoir (1/45). Then, these samples underwent targeted sequencing along with paired tissue DNA. DMG, H3K27-altered patients exhibited a higher ctDNA positivity (85.7%, 12/14) compared to patients with H3-wildtype-astrocytoma (0/8, P = 0.0003), ependymoma (2/10, P = 0.003), and glioneuronal tumor (0/3, P = 0.009). The histological-grade-IV (P = 0.0027), Ki-67 index ≥10% (P = 0.014), and tumor reaching spinal cord surface (P = 0.012) are also associated with higher ctDNA positivity. Interestingly, for patients with TERT promoter mutant tumors, TERT mutation was detectable in the CSF cfDNA of one DMG case, but not other five cases with histological-grade-II tumors. Shared copy number variants were exclusively observed in DMG, H3K27-altered, and showed a strong correlation (Correlation = 0.95) between CSF and tissue. Finally, H3K27M mutations in CSF exhibited high diagnostic efficiency for DMG, H3K27-altered (Sensitivity = 85.7%, Specificity = 100.0%, AUC = 0.929). Notably, H3K27M was detectable in CSF from patients with recurrent tumors, making it easily applicable for postoperative monitoring. In conclusion, the molecular profile from ctDNA released into CSF of malignant tumors was more frequently detected compared to relatively benign ones. Sequencing of ctDNA in CSF exhibited high efficiency for the differential diagnosis of DMG, H3K27-altered.

Intramedullary Spinal Cord Tumors: Whole-Genome Sequencing to Assist Management and Prognosis

Intramedullary spinal cord tumors (IMSCTs) harbor unique genetic mutations which may play a role in prognostication and management. To this end, we present the largest cohort of IMSCTs with genetic characterization in the literature from our multi-site institutional registry. A total of 93 IMSCT patient records were reviewed from the years 1999 to 2020. Out of these, 61 complied with all inclusion criteria, 14 of these patients had undergone genetic studies with 8 undergoing whole-genomic sequencing. Univariate analyses were used to assess any factors associated with progression-free survival (PFS) using the Cox proportional hazards model. Firth's penalized likelihood approach was used to account for the low event rates. Fisher's exact test was performed to compare whole-genome analyses and specific gene mutations with progression. PFS (months) was given as a hazard ratio. Only the absence of copy neutral loss of heterozygosity (LOH) was shown to be significant (0.05, p = 0.008). Additionally, higher risk of recurrence/progression was associated with LOH (p = 0.0179). Our results suggest LOH as a genetic predictor of shorter progression-free survival, particularly within ependymoma and glioblastoma tumor types. Further genomic research with larger multi-institutional datasets should focus on these mutations as possible prognostic factors.

Does H3K27M Mutation Impact Survival Outcome of High-Grade Spinal Cord Astrocytoma?

OBJECTIVE

To evaluate the impact of H3K27M mutation in the prognosis of histological high-grade intramedullary astrocytoma.

METHODS

A total of 78 patients who were diagnosed with high-grade spinal cord astrocytoma were included. Clinical data consisting demographic, radiological, molecular features and treatment data were recorded. Univariate and multivariate Cox analysis were performed to investigate variables associated with survival outcome of histological high-grade spinal cord astrocytoma.

RESULTS

Median survival time was 21 months. Overall survival (OS) at 1 and 3 years was 65.7% and 40.7%, respectively. Sex, location, and tumor span did not present significant association with OS. Patients with H3K27M mutation showed significant shorter duration of symptom than patients with H3K27 wild-type. As respect to adjuvant treatment, adjuvant radiotherapy and chemotherapy were associated with favorable OS (both p = 0.01). Younger patients (age ≤ 18 years) had shorter OS (p = 0.008) than adult patients (age > 18 years). Of note, H3K27M mutation did not show significant impact on the survival outcome, regardless of histology grade 3 or grade 4 (p = 0.3).

CONCLUSION

Histological high-grade spinal cord astrocytoma has dismal prognosis. Our study demonstrated that H3K27M mutation did not show significant impact on survival outcome of histological high-grade spinal cord astrocytoma.

Visual genetic typing of glioma using proximity-anchored in situ spectral coding amplification

Gliomas are histologically and genetically heterogeneous tumors. However, classical histopathological typing often ignores the high heterogeneity of tumors and thus cannot meet the requirements of precise pathological diagnosis. Here, proximity-anchored in situ spectral coding amplification (ProxISCA) is proposed for multiplexed imaging of RNA mutations, enabling visual typing of brain gliomas with different pathological grades at the single-cell and tissue levels. The ligation-based padlock probe can discriminate one-nucleotide variations, and the design of proximity primers enables the anchoring of amplicons on target RNA, thus improving localization accuracy. The DNA module-based spectral coding strategy can dramatically improve the multiplexing capacity for imaging RNA mutations through one-time labelling, with low cost and simple operation. One-target-one-amplicon amplification confers ProxISCA the ability to quantify RNA mutation copy number with single-molecule resolution. Based on this approach, it is found that gliomas with higher malignant grades express more genes with high correlation at the cellular and tissue levels and show greater cellular heterogeneity. ProxISCA provides a tool for glioma research and precise diagnosis, which can reveal the relationship between cellular heterogeneity and glioma occurrence or development and assist in pathological prognosis.

Deep learning based on preoperative magnetic resonance (MR) images improves the predictive power of survival models in primary spinal cord astrocytomas

BACKGROUND

Prognostic models for spinal cord astrocytoma patients are lacking due to the low incidence of the disease. Here, we aim to develop a fully automated deep learning (DL) pipeline for stratified overall survival (OS) prediction based on preoperative MR images.

METHODS

A total of 587 patients diagnosed with intramedullary tumors were retrospectively enrolled in our hospital to develop an automated pipeline for tumor segmentation and OS prediction. The automated pipeline included a T2WI-based tumor segmentation model and 3 cascaded binary OS prediction models (1-year, 3-year, and 5-year models). For the tumor segmentation model, 439 cases of intramedullary tumors were used to model training and testing using a transfer learning strategy. A total of 138 patients diagnosed with astrocytomas were included to train and test the OS prediction models via 10 × 10-fold cross-validation using CNNs.

RESULTS

The dice of the tumor segmentation model with the test set was 0.852. The results indicated that the best input of OS prediction models was a combination of T2W and T1C images and the tumor mask. The 1-year, 3-year, and 5-year automated OS prediction models achieved accuracies of 86.0%, 84.0%, and 88.0% and AUCs of 0.881 (95% CI 0.839-0.918), 0.862 (95% CI 0.827-0.901), and 0.905 (95% CI 0.867-0.942), respectively. The automated DL pipeline achieved 4-class OS prediction (<1 year, 1-3 years, 3-5 years, and >5 years) with 75.3% accuracy.

CONCLUSIONS

We proposed an automated DL pipeline for segmenting spinal cord astrocytomas and stratifying OS based on preoperative MR images.

Detection of Glioma-Related Hotspot Mutations Through Sequencing of Cerebrospinal Fluid (CSF)-Derived Circulating Tumor DNA: A Pilot Study on CSF-Based Liquid Biopsy for Primary Spinal Cord Astrocytoma

OBJECTIVE

Although cerebrospinal fluid (CSF)-based liquid biopsy was proved to be practical in molecular analysis of intracranial gliomas, liquid biopsy of primary intramedullary astrocytoma was rarely reported. Given the distinct genomic profiles between primary intramedullary glioma and intracranial astrocytoma, whether the feasibility of CSF-based molecular analysis of intracranial gliomas can be replicated in primary spinal cord astrocytoma needs to be investigated. The aim of this pilot study is to evaluate the feasibility of molecular analysis of primary intramedullary astrocytoma through sequencing CSF-derived circulating tumor DNA (ctDNA).

METHODS

Two grade IV diffuse midline gliomas, 1 grade II, and 1 grade I astrocytoma were included. Intraoperative collection of peripheral blood and CSF samples was conducted, along with postoperative collection of matched tumor tissues. A panel covering the 1,021 most common driver genes of solid tumors was used for targeted DNA sequencing.

RESULTS

CSF-derived ctDNA was detected in 3 CSF samples (2 grade IV diffuse midline gliomas and 1 grade I astrocytoma), 5 mutations were found in both tumor tissues and CSF samples, while 11 mutations and 20 mutations were detected exclusively in tumor tissues and CSF samples, respectively. Importantly, hotspot genetic alterations, including H3F3A K28M, TP53, and ATRX, were identified in CSF and the average mutant allele frequency was often higher in CSF than in tumor tissues.

CONCLUSION

CSF-based liquid biopsy showed potential feasibility for molecular analysis of primary intramedullary astrocytoma through sequencing of ctDNA. This approach may assist in diagnosis and prognostic evaluation of this rare spinal cord tumor.

Contrast-Enhanced Ultrasound in Resection of Spinal Cord Gliomas

BACKGROUND

Intraoperative contrast-enhanced ultrasound (iCEUS) is a relatively new technique for visualizing brain gliomas and can help achieve maximum resection, but its potential in evaluation of spinal cord gliomas has not been well defined. The aim of this study was to describe the iCEUS characterization of and evaluate its role in visualizing intramedullary gliomas.

METHODS

A retrospective review of patients who underwent intramedullary glioma resection with iCEUS guidance from 2019 to 2021 was conducted. An offline analysis was performed to compare and characterize the perfusion features of each glioma.

RESULTS

This study included 36 patients who underwent iCEUS for spinal cord gliomas. iCEUS was performed successfully, and all gliomas were clearly identified. The distribution of contrast agent showed different dynamic phases (arterial, peak, and washout) from those observed in brain gliomas, generally appearing slower and less intense in spinal cord gliomas. iCEUS helped highlight intramedullary gliomas, each of which demonstrated specific iCEUS features depending on the grade. Gross total resection was achieved in 20 patients (55.6%), subtotal resection was achieved in 11 patients (30.6%), and partial resection was achieved in 5 patients (13.8%).

CONCLUSIONS

ICEUS adds valuable information in highlighting spinal cord gliomas in real time. It allows the neurosurgeon to assess the anatomical location of the glioma and delineate the tumor margins. iCEUS could play a potentially important role in guiding spinal cord glioma resection. Further study with more cases is needed to better understand the microbubble distribution dynamics in intramedullary gliomas.

Immunotherapy for Pediatric Brain and Spine Tumors: Current State and Future Directions

BACKGROUND

Brain tumors are the most common solid tumors and the leading cause of cancer-related deaths in children. Incidence in the USA has been on the rise for the last 2 decades. While therapeutic advances in diagnosis and treatment have improved survival and quality of life in many children, prognosis remains poor and current treatments have significant long-term sequelae.

SUMMARY

There is a substantial need for the development of new therapeutic approaches, and since the introduction of immunotherapy by immune checkpoint inhibitors, there has been an exponential increase in clinical trials to adopt these and other immunotherapy approaches in children with brain tumors. In this review, we summarize the current immunotherapy landscape for various pediatric brain tumor types including choroid plexus tumors, embryonal tumors (medulloblastoma, AT/RT, PNETs), ependymoma, germ cell tumors, gliomas, glioneuronal and neuronal tumors, and mesenchymal tumors. We discuss the latest clinical trials and noteworthy preclinical studies to treat these pediatric brain tumors using checkpoint inhibitors, cellular therapies (CAR-T, NK, T cell), oncolytic virotherapy, radioimmunotherapy, tumor vaccines, immunomodulators, and other targeted therapies.

KEY MESSAGES

The current landscape for immunotherapy in pediatric brain tumors is still emerging, but results in certain tumors have been promising. In the age of targeted therapy, genetic tumor profiling, and many ongoing clinical trials, immunotherapy will likely become an increasingly effective tool in the neuro-oncologist armamentarium.

Primary Spinal Cord Astrocytomas: Two-Center Clinical Experience of Low- and High-Grade Lesions

OBJECTIVE

Primary spinal cord astrocytomas are rare, fatal, and poorly studied.

METHODS

This study included a 2-center, retrospective analysis of primary spinal cord astrocytoma patients from 1997 to 2020. Patients with drop metastases or without at least one follow-up were excluded.

RESULTS

Seven World Health Organization grade I, 6 grade II, 7 grade III, and 4 grade IV astrocytoma patients were included. Older patients had higher grades (median 20 years in grade I vs. 36.5 in grade IV). The median follow-up was 15 months. Thirteen patients were discharged to rehabilitation. Eight patients demonstrated radiographic progression. Adjuvant therapy was utilized more in higher grades (5 of 13 grades III vs. all 11 grades IIIIV). Six patients died (1 death in grades III vs. 5 in grades IIIIV). Ten patients had worsened symptoms at the last follow-up. The median progression-free survival in grade I, II, III, and IV tumors was 116, 36, 8, and 8.5 months, respectively. The median overall survival in grade I, II, III, and IV tumors was 142, 69, 19, and 12 months, respectively. Thrombotic complications occurred in 2 patients, one with isocitrate dehydrogenasewild type glioblastoma.

CONCLUSIONS

Outcomes worsen with higher grades and lead to difficult postoperative periods. Clinicians should be vigilant for thromboembolic complications. Further research is needed to understand these rare tumors.

Surgical approaches to intramedullary spinal cord astrocytomas in the age of genomics

Intramedullary astrocytomas represent approximately 30%–40% of all intramedullary tumors and are the most common intramedullary tumor in children. Surgical resection is considered the mainstay of treatment in symptomatic patients with neurological deficits. Gross total resection (GTR) can be difficult to achieve as astrocytomas frequently present as diffuse lesions that infiltrate the cord. Therefore, GTR carries a substantial risk of new post-operative deficits. Consequently, subtotal resection and biopsy are often the only surgical options attempted. A midline or paramedian sulcal myelotomy is frequently used for surgical resection, although a dorsal root entry zone myelotomy can be used for lateral tumors. Intra-operative neuromonitoring using D-wave integrity, somatosensory, and motor evoked potentials is critical to facilitating a safe resection. Adjuvant radiation and chemotherapy, such as temozolomide, are often administered for high-grade recurrent or progressive lesions; however, consensus is lacking on their efficacy. Biopsied tumors can be analyzed for molecular markers that inform clinicians about the tumor’s prognosis and response to conventional as well as targeted therapeutic treatments. Stratification of intramedullary tumors is increasingly based on molecular features and mutational status. The landscape of genetic and epigenetic mutations in intramedullary astrocytomas is not equivalent to their intracranial counterparts, with important difference in frequency and type of mutations. Therefore, dedicated attention is needed to cohorts of patients with intramedullary tumors. Targeted therapeutic agents can be designed and administered to patients based on their mutational status, which may be used in coordination with traditional surgical resection to improve overall survival and functional status.

PPM1D in Solid and Hematologic Malignancies: Friend and Foe?

In the face of constant genomic insults, the DNA damage response (DDR) is initiated to preserve genome integrity; its disruption is a classic hallmark of cancer. Protein phosphatase Mg2+/Mn2+-dependent 1D (PPM1D) is a central negative regulator of the DDR that is mutated or amplified in many solid cancers. PPM1D overexpression is associated with increased proliferative and metastatic behavior in multiple solid tumor types and patients with PPM1D-mutated malignancies have poorer prognoses. Recent findings have sparked an interest in the role of PPM1D in hematologic malignancies. Acquired somatic mutations may provide hematopoietic stem cells with a competitive advantage, leading to a substantial proportion of mutant progeny in the peripheral blood, an age-associated phenomenon termed "clonal hematopoiesis" (CH). Recent large-scale genomic studies have identified PPM1D to be among the most frequently mutated genes found in individuals with CH. While PPM1D mutations are particularly enriched in patients with therapy-related myeloid neoplasms, their role in driving leukemic transformation remains uncertain. Here, we examine the mechanisms through which PPM1D overexpression or mutation may drive malignancy by suppression of DNA repair, cell-cycle arrest, and apoptosis. We also discuss the divergent roles of PPM1D in the oncogenesis of solid versus hematologic cancers with a view to clinical implications and new therapeutic avenues.

Risk stratification of H3 K27M-mutant diffuse midline gliomas based on anatomical locations: an integrated systematic review of individual participant data

OBJECTIVE

The prognostic significance and genetic characteristics of H3 K27M-mutant diffuse midline gliomas (DMGs) in different anatomical locations requires further clarification. In this study, the authors integrated published data to investigate the differences between brainstem, thalamic, and spinal cord tumors.

METHODS

PubMed and Web of Science databases were used to search for eligible articles. Studies were included if they provided individual patient data of H3 K27M-mutant DMGs with available tumor locations. Hazard ratios (HRs) and 95% confidence intervals (CIs) were computed to investigate the survival of each subgroup.

RESULTS

Eight hundred four tumors were identified, including 467, 228, and 109 in the brainstem, thalamus, and spine, respectively. Brainstem tumors were primarily observed in young children, while patients with thalamic and spinal cord tumors afflicted older patients. The Ki-67 labeling index was highest in brainstem tumors. Compared to patients with brainstem tumors, those with thalamic (HR 0.573, 95% CI 0.463-0.709; p < 0.001) and spinal cord lesions (HR 0.460, 95% CI 0.341-0.621; p < 0.001) had a significantly better survival. When patients were stratified by age groups, superior overall survival (OS) of thalamic tumors was observed in comparison to brainstem tumors in young children and adolescents, whereas adult tumors had uniform OS regardless of anatomical sites. Genetically, mutations in HIST1H3B/C (H3.1) and ACVR1 genes were mostly detected in brainstem tumors, whereas spinal cord tumors were characterized by a higher incidence of mutations in the TERT promoter.

CONCLUSIONS

This study demonstrated that H3 K27M-mutant DMGs have distinct clinical characteristics, prognoses, and molecular profiles in different anatomical locations.

Diffuse midline glioma with H3-K27M mutation: A rare case with GFAP-positive anucleate whorled patterns

INTRODUCTION

Diffuse midline glioma with H3-K27M mutation is an infiltrative high-grade glioma, with predominantly astrocytic differentiation.

PATIENT CONCERNS

A 54-year-old Chinese woman presented with memory loss for a month and walking instability for 15 days.

DIAGNOSIS

Magnetic resonance imaging showed a mass shadow of isometric T1 and slightly longer T2 with mild mixed signals in the third ventricle of the suprasellar region. Histologically, the tumor was primarily sheet-like, with many "anucleate areas" composed of long and thin fibrillary processes of the bipolar cells, which formed "whorls." The neoplastic nuclei were ovoid and moderate in size. The tumor showed brisk mitotic activity and vascular proliferation, with no necrosis. In addition to histone H3K27M mutation, immunohistochemical staining showed that the tumor cells were positive for glial fibrillary acidic protein, oligodendrocyte transcription factor 2, alpha-thalassemia/mental retardation syndrome X, S-100 and Vimentin. The "anucleate areas" were positive for glial fibrillary acidic protein and negative for synaptophysin. The Ki-67 proliferation index was about 10%. Molecular genetic analyses detected H3F3A K27M mutation, but no mutations in IDH1 or IDH2, TERT promoter mutations, MGMT promoter methylation, KIAA1549-BRAF fusion or deletion of 1p/19q were found. Based on these findings, the patient was diagnosed as diffuse midline glioma with H3-K27M mutation in the third ventricle, corresponding to WHO grade 4.

INTERVENTIONS

A craniotomy with total excision of the tumor was performed.

OUTCOMES

After surgery, she was routinely treated with temozolomide for chemotherapy and synchronous radiotherapy. It has been 11 months now, and the patient is living well.

CONCLUSION

This case report provides information on the microscopic morphological features of diffuse midline glioma with H3K27M mutation, which can help pathologists to make a definitive diagnosis of this tumor.

Diffuse Midline Gliomas With Histone H3 K27M Mutation in Adults and Children: A Retrospective Series of 164 Cases

Diffuse midline glioma, H3 K27M-mutant (H3 K27M-mt DMG), is a rare and highly aggressive tumor that is more common in children than in adults. Few studies have compared the differences between pediatric and adult patients with this rare tumor. We here report our retrospective study of 94 adult and 70 pediatric cases of diffuse midline glioma. Surgical tumor samples were analyzed by routine histopathology and immunohistochemistry for H3 K27M, IDH1 R132H, ATRX, p53, OLIG2, glial fibrillary acidic protein, and Ki-67; Sanger sequencing for hot mutation spots in genes including H3F3A, HIST1H3B, IDH1, IDH2, TERT, and BRAF; and methylation-specific polymerase chain reaction for O6-methylguanine DNA methyltransferase promoter methylation. The most frequent anatomic locations in adult and pediatric patients were the thalamus and brainstem, respectively. Molecular profiling revealed higher frequencies of ATRX loss and H3.3 mutation in adult than in pediatric H3 K27M-mt DMGs. TERT promoter mutations and O6-methylguanine DNA methyltransferase promoter methylation were not detected in pediatric patients but were present in a few adult patients. During the follow-up period, 93/122 patients (70.1%) died from the disease, with a median survival time of 10.5 months (range: 1 to 104 mo). Kaplan-Meier analyses demonstrated that the prognosis was better for adult patients than the pediatric cohort (P=0.0003). Multivariate analyses indicated that patient age, primary tumor size, status of ATRX expression, and Ki-67 index were independent prognosticators. The present study showed that there were differences between adult and pediatric H3 K27M-mt DMGs in terms of the anatomic location of tumor, molecular changes, and prognosis.

Recent Molecular and Genetic Findings in Intramedullary Spinal Cord Tumors

The study of genetic alterations and molecular biology in central nervous system (CNS) tumors has improved the accuracy of estimations of patient prognosis and tumor categorization. Therefore, the updated 2021 World Health Organization (WHO) classification includes various diagnostic genes, molecules, and pathways for diagnosis, as well as histological findings. These findings are expected both to have diagnostic applications and to facilitate new targeted therapies that target tumor-specific genetic changes and molecular biology. Intramedullary spinal cord tumors (IMSCTs) are rare CNS tumors that are difficult to treat because they occur in eloquent areas. Although the genetic underpinnings of IMSCTs remain unclear compared to their intracranial counterparts, the genetic characteristics of these tumors are gradually being revealed. Here, we describe the major changes in the new 2021 WHO classification and review the major types of IMSCTs, with an emphasis on their clinical features and genetic alterations.

Prognostic Implication of Patient Age in H3K27M-Mutant Midline Gliomas

Introduction

Pediatric and adult H3K27M-mutant midline gliomas have variable clinical presentations, prognoses, and molecular backgrounds. In this study, we integrated data from published studies to investigate the differences between these two groups.

Methods

PubMed and Web of Science were searched for potential data. Studies were included if they had available individual participant data on patients age of H3K27M-mutant midline gliomas. For time-to-event analyses, Kaplan-Meier analysis and Cox regression models were carried out; corresponding hazard ratios (HR) and 95% confidence intervals (CI) were computed to analyze the impact of age and clinical covariates on progression-free survival (PFS) and overall survival (OS).

Results

We included 43 studies comprising 272 adults and 657 pediatric midline gliomas with H3K27M mutation for analyses. In adults, there was a male predilection whereas females were slightly more common than males in the pediatric group. Spinal cord tumors were more frequent in adults. The prevalence of H3.1 K27M mutation was significantly higher in the pediatric cohort. Compared to adult patients, pediatric H3K27M-mutant midline gliomas exhibited more aggressive features including higher rates of pathologic features of high-grade tumors and Ki67 proliferation index, and had a shorter PFS and OS. Genetically, ACVR1 mutations were more common whereas MGMT methylation, FGFR1, and NF1 mutations were less prevalent in the pediatric cohort.

Conclusion

Pediatric H3K27M-mutant midline gliomas were demographically, clinically, and molecularly distinct from adult patients, highlighting an opportunity to refine the risk stratification for these neoplasms.

Therapeutic Approaches in Adult Primary Spinal Cord Astrocytoma: A Systematic Review

Simple Summary

Adult primary spinal cord astrocytoma (SCA) is a very rare disease, with no standardized consensus about its therapy. We focus on treatment efficacy based on systematic review: only 18 papers were eligible for the analysis, including 285 patients. No clinical trials results were available. Not enough data were extracted to determine a univocal treatment plan for SCA. Given the rarity of these diseases, a collaboration among institutions is mandatory to establish a standard for study conduction (homogenous inclusion criteria and method of analysis), to perform homogenous studies and define future evidence-based recommendation. Contextually, multicentric clinical trials with molecular investigations are strongly advised to better manage SCA and unveil their biology.

Abstract

The issue: Gliomas are primary tumors arising from supporting cells of the central nervous system (CNS), usually in the brain. The 2021 World Health Organization (WHO) classifies gliomas as adult-type diffuse gliomas or circumscribed astrocytic gliomas depending on their histology and molecular features. Spinal astrocytic gliomas are very rare, and nowadays no standard of therapy is available. Treatment options are limited: surgery is often not radical, and adjuvant therapies include mostly radiotherapy (RT) or systemic chemotherapy (CHT). There is lack of knowledge about the efficacy and safety of therapies and their multidisciplinary approaches. The aim of the review: A systematic review of the literature from January 2000 to June 2021 was performed, including both clinical trials and observational studies on histological adult primary spinal cord astrocytomas (SCA), with a minimum follow-up of 6 months and reporting the overall survival, progression-free survival or clinical neurological outcome after any therapeutic approach (surgery, RT or CHT). What are the main findings? A total of 1197 citations were identified by the Medline search and additional records; based on our inclusion criteria, 18 studies were included with a total of 285 adult patients. We documented the lack of any clinical trial. What are the conclusions? The available literature data are limited to series/retrospective studies, including heterogeneous patients, i.e., astrocytoma as well as ependymoma or pediatric/adult age, with scanty data on the outcomes of interest. No clinical trials have been run. Due to the rarity of this disease, multicentric clinical trials with molecular investigations are mandatory to better manage such a rare disease.

Glioma Immunotherapy: Advances and Challenges for Spinal Cord Gliomas

Spinal cord gliomas are rare entities that often have limited surgical options. Immunotherapy has shown promise in intracranial gliomas with some research suggesting benefit for spinal cord gliomas. A focused review of immunotherapies that have been investigated in spinal cord gliomas was performed. The primary methods of immunotherapy investigated in spinal cord gliomas include immune checkpoint inhibitors, adoptive T-cell therapies, and vaccine strategies. There are innumerable challenges that must be overcome to effectively apply immunotherapeutic strategies to the spinal cord gliomas including low incidence, few antigenic targets, the blood spinal cord barrier, the immunosuppressive tumor microenvironment and neurotoxic treatment effects. Nonetheless, research has suggested ways to overcome these challenges and treatments have been effective in case reports for metastatic non-small cell lung cancer, melanoma, midline glioma and glioblastoma. Current therapies for spinal cord gliomas are markedly limited. Further research is needed to determine if the success of immunotherapy for intracranial gliomas can be effectively applied to these unique tumors.

Clinicoradiological characteristics of primary spinal cord H3 K27M-mutant diffuse midline glioma

OBJECTIVE

Primary spinal cord H3 K27M-mutant diffuse midline glioma (DMG) is a rare and devastating pathological entity. However, little attention has been paid to this disease. As a result, its clinicoradiological characteristics have yet to be described. The aim of this study was to describe the clinicoradiological characteristics of primary intramedullary H3 K27M-mutant DMG and to compare this tumor with the H3 K27 wild-type to explore potential features that could differentiate the two.

METHODS

A total of 59 patients with pathologically confirmed intramedullary astrocytoma were included in this study. The cohort was divided into an H3 K27M-mutant group and H3 K27 wild-type group based on the status of H3 K27M according to an immunohistochemistry method. Demographic data, MRI features, and molecular information were collected. Multivariate logistic regression was conducted to investigate variables that might have a role in differentiating an H3 K27M DMG from an H3 K27 wild-type tumor.

RESULTS

Only symptom duration showed an independent association with the H3 K27M mutation (OR 0.82, 95% CI 0.68-0.94, p = 0.016). Patients with spinal cord H3 K27M-mutant DMG had a shorter symptom duration than patients with H3 K27 wild-type glioma. No significant difference was found in terms of MRI features between the H3 K27M-mutant and H3 K27 wild-type groups. Additionally, H3 K27M-mutant DMG frequently demonstrated overexpression of p53. Survival outcome did not show a statistical difference between the H3 K27-mutant subgroup and H3 K27 wild-type subgroup in histologically high-grade astrocytoma.

CONCLUSIONS

Symptom duration was associated with an H3 K27M mutation in intramedullary astrocytoma. MRI features were heterogeneous, and no imaging feature was able to predict the H3 K27M mutation. The H3 K27M mutation did not impact survival outcome in spinal histologically high-grade astrocytoma.

Spinal Cord Diffuse Midline Glioma, H3K27M- mutant Effectively Treated with Bevacizumab: A Report of Two Cases

“Diffuse midline glioma (DMG), H3K27M-mutant” was newly classified in the revised World Health Organization (WHO) 2016 classification of central nervous system tumors. Spinal cord DMG, H3K27M-mutant is relatively rare, with poor prognosis, and there are no effective treatment protocols. In this study, we report two cases of spinal cord DMG, H3K27M-mutant treated with bevacizumab. The two patients were women in their 40s who initially presented with sensory impairment. MRI showed spinal intramedullary tumors, and each patient underwent laminectomy/laminoplasty and biopsy of the tumors. Histological examination initially suggested low-grade astrocytoma in case 1 and glioblastoma in case 2. Upon further immunohistochemical examination in case 1 and molecular examination in case 2, however, both cases were diagnosed as DMG, H3K27M-mutant. Case 1 was treated with radiation therapy and temozolomide (TMZ) chemotherapy, which induced a transient improvement of symptoms; 3 months after surgery, however, the patient’s symptoms rapidly deteriorated. MRI showed tumor enlargement with edema to the medulla. Triweekly administration of bevacizumab improved her symptoms for the following 12 months. Case 2 was treated with bevacizumab from the beginning because of acute deterioration of breathing. After bevacizumab administration, both cases showed tumor regression on MRI and drastic improvement of symptoms within a few days. Although spinal cord DMG, H3K27M-mutant has an aggressive clinical course and poor prognosis, bevacizumab administration may offer the significant clinical benefit of alleviating edema, which improves patient’s capacity for activities of daily life.

Prognostic Factors Independently Associated With Improved Progression-Free Survival After Surgical Resection in Patients With Spinal Cord Astrocytomas: An Institutional Case Series

BACKGROUND

Spinal astrocytomas are rare tumors in which the extent of resection and adjuvant therapy remain controversial. A number of new molecular markers are used, but their utility in spinal cord tumors remains unclear.

OBJECTIVE

To determine prognostic indicators of progression-free survival (PFS) in patients with spinal astrocytomas.

METHODS

A retrospective chart review identified all patients managed at a single institution for spinal cord astrocytomas between 1999 and 2019. Data collected included baseline demographics, presenting signs and symptoms, tumor size, operative outcomes, and adjuvant treatment. Pathological data including histopathological grade, proliferative index, and molecular profile were collected. Duration of follow-up, presence of tumor progression, and status at last follow-up were documented. Univariate and multivariate analyses were performed to determine predictors of PFS.

RESULTS

Seventy-five patients were included in our study with an average age of 42 ± 17 yr. The thoracic spine was the most commonly involved spinal segment (50 patients), and most patients had grade I or grade II tumors (50 patients). On univariate analysis, gross total resection (GTR), lower tumor grade, and low Ki-67 index were associated with lower tumor progression (P-values .01, .04, and .00013, respectively). On multivariate Cox regression analysis, GTR, adjuvant chemotherapy and radiation, and low Ki-67 index were independent predictors of PFS (P-values .009, .011, and .031, respectively).

CONCLUSION

In spinal astrocytomas, GTR, adjuvant therapy, and low Ki-67 are independently associated with improved PFS. These data may help guide management of these tumors and provide important prognosticating information.

Patterns of failure after radiation therapy in primary spinal high-grade gliomas: A single institutional analysis

Background

Primary spinal high-grade gliomas (S-HGG) are rare aggressive tumors; radiation therapy (RT) often plays a dominant role in management. We conducted a single-institution retrospective review to study the clinicopathological features and management of S-HGGs.

Methods

Patients with biopsy-proven S-HGG who received RT from 2001 to 2020 were analyzed for patient, tumor, and treatment characteristics. Kaplan–Meier estimates were used for survival analyses.

Results

Twenty-nine patients were identified with a median age of 25.9 years (range 1–74 y). Four patients had GTR while 25 underwent subtotal resection or biopsy. All patients were IDH wildtype and MGMT-promoter unmethylated, where available. H3K27M mutation was present in 5 out of 10 patients tested, while one patient harbored p53 mutation. Median RT dose was 50.4 Gy (range 39.6–54 Gy) and 65% received concurrent chemotherapy, most commonly temozolomide. Twenty-three (79%) of patients had documented recurrence. Overall, 16 patients relapsed locally, 10 relapsed in the brain and 8 developed leptomeningeal disease; only 8 had isolated local relapse. Median OS from diagnosis was 21.3 months and median PFS was 9.7 months. On univariate analysis, age, gender, GTR, grade, RT modality, RT dose and concurrent chemotherapy did not predict for survival. Patients with H3K27M mutation had a poorer PFS compared to those without mutation (10.1 m vs 45.1 m) but the difference did not reach statistical significance (P = .26).

Conclusions

The prognosis of patients with spinal HGGs remains poor with two-thirds of the patients developing distant recurrence despite chemoradiation. Survival outcomes were similar in patients ≤ 29 years compared to adults > 29 years. A better understanding of the molecular drivers of spinal HGGs is needed to develop more effective treatment options.

A multicenter analysis of the prognostic value of histone H3 K27M mutation in adult high-grade spinal glioma

OBJECTIVE

High-grade spinal glioma (HGSG) is a rare but aggressive tumor that occurs in both adults and children. Histone H3 K27M mutation correlates with poor prognosis in children with diffuse midline glioma. However, the role of H3 K27M mutation in the prognosis of adults with HGSG remains unclear owing to the rarity of this mutation, conflicting reports, and the absence of multicenter studies on this topic.

METHODS

The authors studied a cohort of 30 adult patients with diffuse HGSG who underwent histological confirmation of diagnosis, surgical intervention, and treatment between January 2000 and July 2020 at six tertiary academic centers. The primary outcome was the effect of H3 K27M mutation status on progression-free survival (PFS) and overall survival (OS).

RESULTS

Thirty patients (18 males and 12 females) with a median (range) age of 50.5 (19-76) years were included in the analysis. Eighteen patients had H3 K27M mutation-positive tumors, and 12 had H3 K27M mutation-negative tumors. The median (interquartile range) PFS was 3 (10) months, and the median (interquartile range) OS was 9 (23) months. The factors associated with increased survival were treatment with concurrent chemotherapy/radiation (p = 0.006 for PFS, and p ≤ 0.001 for OS) and American Spinal Injury Association grade C or better at presentation (p = 0.043 for PFS, and p < 0.001 for OS). There were no significant differences in outcomes based on tumor location, extent of resection, sex, or H3 K27M mutation status. Analysis restricted to HGSG containing necrosis and/or microvascular proliferation (WHO grade IV histological features) revealed increased OS for patients with H3 K27M mutation-positive tumors (p = 0.017).

CONCLUSIONS

Although H3 K27M mutant-positive HGSG was associated with poor outcomes in adult patients, the outcomes of patients with H3 K27M mutant-positive HGSG were somewhat more favorable compared with those of their H3 K27M mutant-negative HGSG counterparts. Further preclinical animal studies and larger clinical studies are needed to further understand the age-dependent effects of H3 K27M mutation.

H3K27M-mutant diffuse midline gliomas should be further molecularly stratified: an integrated analysis of 669 patients

INTRODUCTION

H3K27M-mutated diffuse midline gliomas (H3-DMGs) are aggressive tumors with a fatal outcome. This study integrating individual patient data (IPD) from published studies aimed to investigate the prognostic impact of different genetic alterations on survival of these patients.

METHODS

We accessed PubMed and Web of Science to search for relevant articles. Studies were included if they have available data of follow-up and additional molecular investigation of H3-DMGs. For survival analysis, Kaplan-Meier analysis and Cox regression models were utilized, and corresponding hazard ratios (HR) and 95% confidence intervals (CI) were computed to analyze the impact of genetic events on overall survival (OS).

RESULT

We included 30 studies with 669 H3-DMGs. TP53 mutations were the most common second alteration among these neoplasms. In univariate Cox regression model, TP53 mutation was an indicator of shortened survival (HR 1.446; 95% CI 1.143-1.829) whereas ACVR1 (HR 0.712; 95% CI 0.518-0.976) and FGFR1 mutations (HR 0.408; 95% CI 0.208-0.799) conferred prolonged survival. In addition, ATRX loss was also associated with a better OS (HR 0.620; 95% CI 0.386-0.996). Adjusted for age, gender, and tumor location, the presence of TP53 mutations, the absence of ACVR1 or FGFR1 mutations remained significantly poor prognostic factors.

CONCLUSIONS

We outlined the prognostic importance of additional genetic alterations in H3-DMGs and recommended that these neoplasms should be further molecularly segregated. This may aid neuro-oncologists in appropriate risk stratification.

Analyses of DNA Methylation Profiling in the Diagnosis of Intramedullary Astrocytomas

Intramedullary astrocytomas (IMAs) consist of a heterogeneous group of rare central nervous system (CNS) tumors associated with variable outcomes. A DNA methylation-based classification approach has recently emerged as a powerful tool to further classify CNS tumors. However, no DNA methylation-related studies specifically addressing to IMAs have been performed yet. In the present study, we analyzed 16 IMA samples subjected to morphological and molecular analyses, including DNA methylation profiling. Among the 16 samples, only 3 cases were classified in a reference methylation class (MC) with the recommended calibrated score (≥0.9). The remaining cases were either considered “no-match” cases (calibrated score <0.3, n = 7) or were classified with low calibrated scores (ranging from 0.32 to 0.53, n = 6), including inconsistent classification. To obtain a more comprehensive tool for pathologists, we used different unsupervised analyses of DNA methylation profiles, including our data and those from the Heidelberg reference cohort. Even though our cohort included only 16 cases, hypotheses regarding IMA-specific classification were underlined; a potential specific MC of PA_SPINE was identified and high-grade IMAs, probably consisting of H3K27M wild-type IMAs, were mainly associated with ANA_PA MC. These hypotheses strongly suggest that a specific classification for IMAs has to be investigated.

Diffuse Gliomas of the Brainstem and Cerebellum in Adults Show Molecular Heterogeneity

Posterior fossa (PF) diffuse gliomas in pediatric patients frequently harbor the H3 K27M mutation. Among adults, PF diffuse gliomas are rare, with limited data regarding molecular features and clinical outcomes. We identified 28 adult PF diffuse glioma patients (17 males; median: 50 y, range: 19 to 78 y), with surgery performed at our institution (13 brainstem; 15 cerebellum). Histologic subtypes included anaplastic astrocytoma (n=21), glioblastoma (n=6), and diffuse astrocytoma (n=1). Immunohistochemistry was performed for H3 K27M (n=26), IDH1-R132H (n=28), and ATRX (n=28). A 150-gene neuro-oncology-targeted next-generation sequencing panel was attempted in 24/28, with sufficient informative material in 15 (51.7%). Tumors comprised 4 distinct groups: driver mutations in H3F3A (brainstem=4; cerebellum=2), IDH1 (brainstem=4; cerebellum=4), TERT promotor mutation (brainstem=0; cerebellum=3), and none of these (n=5), with the latter harboring mutations of TP53, PDGFRA, ATRX, NF1, and RB1. All TERT promoter-mutant cases were IDH-wild-type and arose within the cerebellum. To date, 20 patients have died of disease, with a median survival of 16.3 months, 1-year survival of 67.5%. Median survival within the subgroups included: H3F3A=16.4 months, IDH mutant=113.4 months, and TERT promoter mutant=12.9 months. These findings suggest that PF diffuse gliomas affecting adults show molecular heterogeneity, which may be associated with patient outcomes and possible response to therapy, and supports the utility of molecular testing in these tumors.

Molecular diagnostics helps to identify distinct subgroups of spinal astrocytomas

Primary spinal cord astrocytomas are rare, hence few data exist about the prognostic significance of molecular markers. Here we analyze a panel of molecular alterations in association with the clinical course. Histology and genome sequencing was performed in 26 spinal astrocytomas operated upon between 2000 and 2020. Next-generation DNA/RNA sequencing (NGS) and methylome analysis were performed to determine molecular alterations. Histology and NGS allowed the distinction of 5 tumor subgroups: glioblastoma IDH wildtype (GBM); diffuse midline glioma H3 K27M mutated (DMG-H3); high-grade astrocytoma with piloid features (HAP); diffuse astrocytoma IDH mutated (DA), diffuse leptomeningeal glioneural tumors (DGLN) and pilocytic astrocytoma (PA). Within all tumor entities GBM (median OS: 5.5 months), DMG-H3 (median OS: 13 months) and HAP (median OS: 8 months) showed a fatal prognosis. DMG-H3 tend to emerge in adolescence whereas GBM and HAP develop in the elderly. HAP are characterized by CDKN2A/B deletion and ATRX mutation. 50% of PA tumors carried a mutation in the PIK3CA gene which is seemingly associated with better outcome (median OS: PIK3CA mutated 107.5 vs 45.5 months in wildtype PA). This exploratory molecular profiling of spinal cord astrocytomas allows to identify distinct subgroups by combining molecular markers and histomorphology. DMG-H3 tend to develop in adolescence with a similar dismal prognosis like GBM and HAP in the elderly. We here describe spinal HAP with a distinct molecular profile for the first time.

Suppression of miR-106a-5p expression inhibits tumorigenesis via increasing CELF-2 expression in spinal cord glioma

Spinal cord glioma is a tumor characterized by high recurrence and mortality rates, and its treatment remains a major challenge. It has been reported that abnormal expression of microRNAs (miRNAs/miRs) is associated with tumor progression. Therefore, the current study aimed to identify novel miRNAs associated with spinal cord glioma. Herein, the expression levels of several miRNAs were determined in human spinal cord glioma and adjacent non-cancerous tissues by reverse transcription-quantitative (RT-qPCR). The results revealed that miR-106a-5p expression was markedly upregulated in spinal cord glioma tissues compared with in non-cancerous tissues. Furthermore, the biological effects of miR-106a-5p on spinal cord glioma cells were evaluated by MTT, Transwell and flow cytometric assays. In 0231SCG cells transfected with miR-106a-5p inhibitor, cell proliferation, migration and invasion were attenuated, whereas apoptosis was enhanced. A search of the TargetScan database revealed that miR-106a-5p directly targeted CUGBP Elav-like family member 2 (CELF-2). Western blot and RT-qPCR experiments further confirmed the association between miR-106a-5p and CELF-2 expression in spinal cord glioma tissues. The current results demonstrated that CELF-2 was a direct target of miR-106a-5p, and that the expression levels of CELF-2 were negatively associated with those of miR-106a-5p. In addition, overexpression of CELF-2 in spinal cord glioma cells reversed the tumor-promoting effects of miR-106a-5p both in vitro and in vivo. Overall, the aforementioned findings indicated that miR-106a-5p, which was highly expressed in spinal cord glioma tissues, may affect the proliferation, migration, invasion and apoptosis of spinal cord glioma cells via targeting CELF-2, thus indicating a potential approach to the future clinical management of spinal cord glioma.

Spinal Cord Diffuse Midline Gliomas With H3 K27m-Mutant: Clinicopathological Features and Prognosis

BACKGROUND

"Diffuse midline glioma, H3 K27M-mutant" (DMG) mainly arises within the pontine, thalamic, and spinal cord regions. Because of the rarity of spinal cord gliomas, the general knowledge surrounding DMGs is mainly based on pontine and thalamic gliomas, whereas tumor location tends to influence the clinicopathological features and prognosis.

OBJECTIVE

To determine the clinicopathological characteristics and molecular profiles of DMGs located in the spinal cord.

METHODS

The clinical and molecular pathologic features and prognosis were comprehensively analyzed in a series of 44 patients with spinal cord DMGs.

RESULTS

The median age was 36 yr, and 88.7% of patients (39/44) were adults (≥18 yr). Histopathologically, malignant grades included grade II (16 cases), grade III (20 cases), and grade IV (8 cases). Compared with patients with histological grade IV, patients with lower histological grade (grade II/III) were older (37 vs 24 yr, P = .020) and were associated with longer overall survival (24.1 vs 8.6 mo, P = .007). All 30 tested tumors were isocitrate dehydrogenase (IDH) wild type, and 96% of cases (22/23) presented with unmethylated O6-methylguanine-DNA methyltransferase. Univariate and multivariate analyses showed that histological grade and presurgery McCormick Scale scores were independent prognostic factors for overall survival, whereas extensive surgical resection and chemoradiotherapy were not significantly associated with improved survival. The most frequent anatomic locations were the cervical enlargement (C4-T1, n = 16) and conus medullaris (T12-L1, n = 13), which exhibited distinctive clinical characteristics and molecular features.

CONCLUSION

The findings provide guidelines for the evidence-based practice of the specialized management of spinal cord DMGs.

Diffuse midline glioma with H3 K27M mutation of the spinal cord: A series of 33 cases

We investigated the risk factors for diffuse midline gliomas of the spinal cord (DMGSCs). Seventy patients with spinal cord gliomas in two hospitals were analyzed retrospectively. Sixty-nine patients that underwent surgery achieved partial or gross total removal. The patients were subdivided into some groups, based on age, WHO grade, tumor location within the cord, tumor size, and molecular profile: immunohistochemical expression of p53 and ATRX, and mutational status of Histone 3 (H3), and BRAF. Thirty-three patients had an H3 K27M mutation (47%). Some clinical characteristics were significantly different between H3 K27M mutant and H3 wild-type tumors. The main risk factors for DMGSCs were male sex, glioblastomas, and ≤ 2 spinal cord segments. The median survival period of patients with H3 K27M mutant tumors was significantly shorter than those with H3 wild-type tumors (17.0 ± 3.7 months vs censored, P < 0.0001). In the DMGSC subgroup, patients with thoracic cord tumors had a significantly better prognosis than those with cervical cord tumors (31.0 ± 6.0 vs 10.0 ± 4.8 months). Patients > 45 years of age survived significantly longer than patients < 19 years (P = 0.001). In conclusion, H3 K27M mutation significantly predicts a worse outcome of spinal cord gliomas. Anatomical location and age are the main risk factors for DMGSCs.

Immunotherapy: A Potential Approach for High-Grade Spinal Cord Astrocytomas

Spinal cord astrocytomas (SCAs) account for 6–8% of all primary spinal cord tumors. For high-grade SCAs, the prognosis is often poor with conventional therapy, thus the urgent need for novel treatments to improve patient survival. Immunotherapy is a promising therapeutic strategy and has been used to treat cancer in recent years. Several clinical trials have evaluated immunotherapy for intracranial gliomas, providing evidence for immunotherapy-mediated ability to inhibit tumor growth. Given the unique microenvironment and molecular biology of the spinal cord, this review will offer new perspectives on moving toward the application of successful immunotherapy for SCAs based on the latest studies and literature. Furthermore, we will discuss the challenges associated with immunotherapy in SCAs, propose prospects for future research, and provide a periodic summary of the current state of immunotherapy for SCAs immunotherapy.

Neoplastic Myelopathies

PURPOSE OF REVIEW

This article reviews the current classification system of primary spinal cord tumors and explores evolving diagnostic and therapeutic strategies for both primary tumors and metastatic tumors to various compartments of the spinal cord.

RECENT FINDINGS

The 2016 World Health Organization classification system allows for more precise prognostication of and therapy for spinal cord tumors and has identified new entities, such as the diffuse midline glioma, H3 K27M mutant. Whole-exome sequencing reveals that the genetic background of primary glial spinal cord neoplasms differs from that of their intracranial histologic counterparts in ways that can potentially influence therapy. Targeted and immune checkpoint therapies have improved survival for patients with melanoma and lung cancer and have simultaneously produced novel complications by enhancing radiation toxicity in some cases and by facilitating the emergence of novel autoimmune and paraneoplastic syndromes involving the spinal cord, such as neuromyelitis optica spectrum disorder and syndromes associated with anti-Hu and collapsin response mediator protein-5 (CRMP-5) antibodies. These conditions must be distinguished from tumor or infection. Epidural spinal cord compression treatment paradigms have changed with the advent of robotic surgery and advances in radiation therapy.

SUMMARY

Neoplastic myelopathies subsume a wide spectrum of pathologies. Neoplastic cord involvement may be primary or secondary and may be approached diagnostically by the particular spinal cord compartment localization. Primary spinal cord tumors account for only 2% to 4% of primary central nervous system tumors, ranging from low-grade glial neoplasms to malignant tumors. Metastatic malignancy to the epidural or leptomeningeal spaces is more common than primary cord tumors. Differential diagnoses arising in the course of evaluation for cord tumors include myelopathies related to radiation or chemotherapy and paraneoplastic syndromes, all of which are sources of significant morbidity. Knowledge of genetic syndromes and the biologic behavior of diverse histologies together with selective application of surgery, radiation, and targeted therapies can facilitate diagnosis, minimize surgical morbidity, and prolong quality of life.

A comprehensive model including preoperative peripheral blood inflammatory markers for prediction of the prognosis of diffuse spinal cord astrocytoma following surgery

PURPOSE

Due to the rarity of diffuse spinal cord astrocytoma, an effective model is still lacking to stratify their prognosis. Here, we aimed to establish a prognostic model through comprehensively evaluating clinicopathological features and preoperative peripheral blood inflammatory markers in 89 cases.

METHODS

We performed univariate and multivariate Cox regression to identify prognosis factors. The Kaplan-Meier curves and ROC curves were employed to compare the prognostic value of selected factors.

RESULTS

In addition to clinicopathological factors, we revealed the preoperative peripheral blood leukocyte count, neutrophils-to-lymphocytes ratio (NLR), and platelet-to-lymphocyte ratio (PLR) were also significantly correlated with overall survival of spinal cord astrocytoma in univariate Cox regression, and NLR was still significant in multivariate Cox analysis. Further, we demonstrated that NLR ≤ 3.65 and preoperative McCormick score (MMS) ≤ 3 were independently correlated with better survival of WHO grade IV tumors. Meanwhile, Ki-67 < 10% and resection extent ≥ 90% were independent prognostic factors in WHO grade II/III tumors. Finally, we developed a prognostic model that had better predictive efficiencies than WHO grade and histological grade for 1-year (AUC = 76.6), 2- year (AUC = 80.9), and 3-year (AUC = 80.3) survival. This model could classify tumors into 4 classifications with increasingly poor prognosis: 1, WHO grade II/III, with Ki-67 < 10% and resection extent ≥ 90%; 2, WHO grade II/III, Ki-67 ≥ 10% or resection < 90%; 3, WHO grade IV, NLR ≤ 3.65 and MMS ≤ 3; 4, WHO grade IV, with NRL > 3.65 or MMS = 4.

CONCLUSION

We successfully constructed a comprehensive prognostic model including preoperative peripheral blood inflammatory markers, which can stratify diffuse spinal cord astrocytoma into 4 subgroups.

Pediatric primary high-grade spinal glioma: a National Cancer Database analysis of current patterns in treatment and outcomes

PURPOSE

Pediatric primary high-grade spinal glioma (p-HGSG) is an extremely rare disease process, with little data within the current literature. Akin to primary high-grade gliomas, this cancer has been exemplified by dismal prognosis and poor response to modern treatment paradigms. This study seeks to investigate the current trends affecting overall survival using the National Cancer Database (NCDB).

METHODS

The NCDB was queried for p-HGSG between 2004 and 2016, by utilizing the designated diagnosis codes. Kaplan-Meier curves were generated, and log-rank testing was performed to analyze factors affecting overall survival. In addition, a Cox proportional-hazards model was used to perform multivariate regression analysis of survival outcomes.

RESULTS

A cohort of 97 patients was identified with a histologically confirmed p-HGSG. The overall incidence of p-HGSG in all pediatric spinal cord tumors is 7.5%, with a mean survival time of 25.3 months (SD, 21.0) and 5-year overall survival of 17.0%. The majority of patients underwent surgery (n = 87, 89.7%), radiotherapy (n = 73, 75.3%), and chemotherapy (n = 60, 61.9%). Univariate, multivariate, and Kaplan-Meier log-rank testing failed to demonstrate an association between performing surgery, extent of resection, radiotherapy, or chemotherapy with improved survival outcomes.

CONCLUSIONS

The current study constitutes the largest retrospective analysis of p-HGSGs to date, finding that current treatment options of surgery, radiotherapy, and chemotherapy have unclear benefit. This disease process has a poor prognosis without a current modality of treatment that conclusively alters survival. The risks and side effects of these treatment modalities must be carefully considered in such a highly aggressive disease process, especially given potentially limited survival benefits.

Clinical, radiological and molecular characterization of intramedullary astrocytomas

Intramedullary astrocytomas (IMAs) are rare tumors, and few studies specific to the molecular alterations of IMAs have been performed. Recently, KIAA1549-BRAF fusions and the H3F3A p.K27M mutation have been described in low-grade (LG) and high-grade (HG) IMAs, respectively. In the present study, we collected clinico-radiological data and performed targeted next-generation sequencing for 61 IMAs (26 grade I pilocytic, 17 grade II diffuse, 3 LG, 3 grade III and 12 grade IV) to identify KIAA1549-BRAF fusions and mutations in 33 genes commonly implicated in gliomas and the 1p/19q regions. One hundred seventeen brain astrocytomas were analyzed for comparison. While we did not observe a difference in clinico-radiological features between LG and HG IMAs, we observed significantly different overall survival (OS) and event-free survival (EFS). Multivariate analysis showed that the tumor grade was associated with better OS while EFS was strongly impacted by tumor grade and surgery, with higher rates of disease progression in cases in which only biopsy could be performed. For LG IMAs, EFS was only impacted by surgery and not by grade. The most common mutations found in IMAs involved TP53, H3F3A p.K27M and ATRX. As in the brain, grade I pilocytic IMAs frequently harbored KIAA1549-BRAF fusions but with different fusion types. Non-canonical IDH mutations were observed in only 2 grade II diffuse IMAs. No EGFR or TERT promoter alterations were found in IDH wild-type grade II diffuse IMAs. These latter tumors seem to have a good prognosis, and only 2 cases underwent anaplastic evolution. All of the HG IMAs presented at least one molecular alteration, with the most frequent one being the H3F3A p.K27M mutation. The H3F3A p.K27M mutation showed significant associations with OS and EFS after multivariate analysis. This study emphasizes that IMAs have distinct clinico-radiological, natural evolution and molecular landscapes from brain astrocytomas.

Prognostic role of H3K27M mutation, histone H3K27 methylation status, and EZH2 expression in diffuse spinal cord gliomas

The objective of this study is to clarify clinical significance of the H3F3A K27M mutation (H3K27M) and analyze the correlation between H3K27M, H3K27me3 status, and EZH2 expression and prognosis in spinal cord gliomas. Patients with spinal cord diffuse glioma regardless of World Health Organization (WHO) grade underwent genetic analysis for H3F3A, HIST1H3B, TERT promoter, IDH1/2, and BRAF. H3K27me3 status and EZH2 expression were analyzed through immunohistochemistry. Thereafter, the association between H3K27M, H3K27me3 status, and EZH2 expression and prognosis was retrospectively analyzed using the log-rank test. A total of 26 cases, 5 with WHO grade 4, 9 with grade 3, and 12 with grade 2 glioma, were analyzed. Although WHO grade 2 cases tended to present favorable overall survival, the difference was not statistically significant. H3K27M, which was detected in four grade 4 cases (80%) and three grade 3 cases (33%), was not associated with prognosis among grade 3 and 4 cases. Among WHO grade 2-4 cases, the combination of retained H3K27me3 and negative EZH2 expression was correlated with favorable overall survival (p = 0.03). The combination of H3K27me3 status and EZH2 expression was considered as a potential prognostic marker in WHO grade 2-4 diffuse spinal cord gliomas.

The molecular characteristics of spinal cord gliomas with or without H3 K27M mutation

Due to the rare incidence of spinal cord astrocytomas, their molecular features remain unclear. Here, we characterized the landscapes of mutations in H3 K27M, isocitrate dehydrogenase 1 (IDH1) R132H, BRAF V600E, and the TERT promoter in 83 diffuse spinal cord astrocytic tumors. Among these samples, thirty-five patients had the H3 K27M mutation; this mutant could be observed in histological grade II (40%), III (40%), and IV (20%) astrocytomas. IDH1 mutations were absent in 58 of 58 cases tested. The BRAF V600E mutation (7/57) was only observed in H3-wildtype astrocytomas, and was associated with a better prognosis in all histological grade II/III astrocytomas. TERT promoter mutations were observed in both H3 K27M-mutant (4/25) and -wildtype (9/33) astrocytomas, and were associated with a poor prognosis in H3-wildtype histological grade II/III astrocytomas. In the 2016 WHO classification of CNS tumors, H3 K27M-mutant diffuse midline gliomas, including spinal cord astrocytomas, are categorized as WHO grade IV. Here, we noticed that the median overall survival of histological grade II/III H3 K27M-mutant cases (n = 28) was significantly longer than that of either the total histological grade IV cases (n = 12) or the H3 K27M-mutant histological grade IV cases (n = 7). We also directly compared H3 K27M-mutant astrocytomas to H3-wildtype astrocytomas of the same histological grade. In histological grade II astrocytomas, compared to H3-wildtype cases (n = 37), H3 K27M-mutant patients (n = 14) had showed a significantly higher Ki-67-positive rate and poorer survival rate. However, no significant differences in these parameters were observed in histological grade III and IV astrocytoma patients. In conclusion, these findings indicate that spinal cord astrocytomas are considerably different from hemispheric and brainstem astrocytomas in terms of their molecular profiles, and that the histological grade cannot be ignored when assessing the prognosis of H3 K27M-mutant spinal cord astrocytomas.

Spinal cord anaplastic astrocytoma with BRAF V600E mutation: A case report and review of literature

A 17-year-old female complained of lower extremity pain that progressed to low back pain accompanied by paraparesis. Magnetic resonance imaging revealed a mass in the conus medullaris of the spinal cord at the thoracic spine 11-12 level. The patient underwent resection of the mass. The pathological diagnosis was anaplastic astrocytoma based on the densely proliferating astrocytic tumor cells without necrosis or microvascular proliferation. The patient received chemoradiotherapy with oral temozolomide and a total of 54 Gy of local irradiation, followed by 24 courses of temozolomide as maintenance chemotherapy. The patient survived for 8 years without tumor recurrence following the initial treatment. Genetic analysis of the tumor revealed a BRAF V600E mutation that has not yet been reported in spinal cord high-grade gliomas (HGGs). In recent years, the molecular therapy targeting the BRAF V600E mutation has been applied in clinical practice for several cancer types. Although the frequency in spinal cord HGGs is uncertain, it is necessary to investigate BRAF V600E mutation as a potential therapeutic target in the future.