The specific DNA methylation landscape in focal cortical dysplasia ILAE type 3D.

Focal Cortical Dysplasia (FCD) is a frequent cause of drug-resistant focal epilepsy in children and young adults. The international FCD classifications of 2011 and 2022 have identified several clinico-pathological subtypes, either occurring isolated, i.e., FCD ILAE Type 1 or 2, or in association with a principal cortical lesion, i.e., FCD Type 3. Here, we addressed the DNA methylation signature of a previously described new subtype of FCD 3D occurring in the occipital lobe of very young children and microscopically defined by neuronal cell loss in cortical layer 4. We studied the DNA methylation profile using 850 K BeadChip arrays in a retrospective cohort of 104 patients with FCD 1 A, 2 A, 2B, 3D, TLE without FCD, and 16 postmortem specimens without neurological disorders as controls, operated in China or Germany. DNA was extracted from formalin-fixed paraffin-embedded tissue blocks with microscopically confirmed lesions, and DNA methylation profiles were bioinformatically analyzed with a recently developed deep learning algorithm. Our results revealed a distinct position of FCD 3D in the DNA methylation map of common FCD subtypes, also different from non-FCD epilepsy surgery controls or non-epileptic postmortem controls. Within the FCD 3D cohort, the DNA methylation signature separated three histopathology subtypes, i.e., glial scarring around porencephalic cysts, loss of layer 4, and Rasmussen encephalitis. Differential methylation in FCD 3D with loss of layer 4 mapped explicitly to biological pathways related to neurodegeneration, biogenesis of the extracellular matrix (ECM) components, axon guidance, and regulation of the actin cytoskeleton. Our data suggest that DNA methylation signatures in cortical malformations are not only of diagnostic value but also phenotypically relevant, providing the molecular underpinnings of structural and histopathological features associated with epilepsy. Further studies will be necessary to confirm these results and clarify their functional relevance and epileptogenic potential in these difficult-to-treat children.

Case report: Late in-stent thrombosis in a patient with vertebrobasilar dolichoectasia after stent-assisted coil embolization due to the discontinuation of antiplatelet therapy.

Vertebrobasilar dolichoectasia (VBD) is a rare type of cerebrovascular disorder with high rates of morbidity and mortality. Due to the distinct pathological characteristics that fragmented internal elastic lamina and multiple dissections, VBD is difficult to treat and cured. Stent-assisted coil embolization is one of the main treatment modalities for such lesions. However, the duration of healing remained questionable, and there were no effective measures for evaluating endothelial coverage. Before complete endothelial coverage, the discontinuation of antiplatelet therapy may lead to fatal in-stent thrombosis; however, continued antiplatelet therapy could also result in bleeding complications. Thus, we present an autopsy case of late in-stent thrombosis due to the discontinuation of antiplatelet therapy and systematically review the literature to provide a reference for endovascular treatment and antiplatelet regimen of VBD.

The clinico-pathological characterisation of focal cortical dysplasia type IIb genetically defined by MTOR mosaicism.

AIMS: Focal cortical dysplasia (FCD) is a major cause of drug-resistant paediatric epilepsy and is amenable to successful neurosurgical resection. FCD ILAE Type IIb is the most common FCD subtype, and brain somatic mutations affecting the mTOR pathway play a major pathogenic role. The aim of this study was to comprehensively describe the genotype-phenotype association of 20 patients with histopathologically confirmed FCDIIb using next generation sequencing (NGS) of paired blood-brain samples. METHODS: Clinical and neuropathological data were retrospectively reviewed from the hospital archive. The NGS panel included 11 mTOR-pathway-related genes with maximum coverage of 2000×. The detected variants were validated by digital droplet PCR. RESULTS: Pathogenic MTOR variants were identified in 10 patients (50%). Further comparison with MTOR-wildtype FCDIIb suggested a profound genotype-phenotype association characterised by (1) a non-temporal lobe lesion on MRI, (2) a larger lesion volume occupying grey and white matter (3.032 ± 1.859 cm3 vs 1.110 ± 0.856 cm3 , p = 0.014), (3) more balloon cells (50.20 ± 14.40 BC/mm2 vs 31.64 ± 30.56 BC/mm2 , p = 0.099) and dysmorphic neurons (48.72 ± 19.47DN/mm2 vs 15.28 ± 13.95DN/mm2 , p = 0.000) and (4) a positive correlation between VAF and the lesion volume (r = 0.802, p = 0.017). CONCLUSIONS: Our study identified frequent MTOR mutations in the cell-rich FCDIIb phenotype, clinically characterised by a non-temporal location and large lesion volume. Comprehensive genotype-phenotype associations will help us further explore and define the broad spectrum of FCD lesions to make more targeted therapies available in the realm of epileptology.

Imbalance between the function of Na+-K+-2Cl and K+-Cl impairs Cl- homeostasis in human focal cortical dysplasia.

Objective: Altered expression patterns of Na+-K+-2Cl- (NKCC1) and K+-Cl- (KCC2) co-transporters have been implicated in the pathogenesis of epilepsy. Here, we assessed the effects of imbalanced NKCC1 and KCC2 on γ-aminobutyric acidergic (GABAergic) neurotransmission in certain brain regions involved in human focal cortical dysplasia (FCD). Materials and methods: We sought to map a micro-macro neuronal network to better understand the epileptogenesis mechanism. In patients with FCD, we resected cortical tissue from the seizure the onset zone (SOZ) and the non-seizure onset zone (non-SOZ) inside the epileptogenic zone (EZ). Additionally, we resected non-epileptic neocortical tissue from the patients with mesial temporal lobe epilepsy (MTLE) as control. All of tissues were analyzed using perforated patch recordings. NKCC1 and KCC2 co-transporters expression and distribution were analyzed by immunohistochemistry and western blotting. Results: Results revealed that depolarized GABAergic signals were observed in pyramidal neurons in the SOZ and non-SOZ groups compared with the control group. The total number of pyramidal neurons showing GABAergic spontaneous postsynaptic currents was 11/14, 7/17, and 0/12 in the SOZ, non-SOZ, and control groups, respectively. The depolarizing GABAergic response was significantly dampened by the specific NKCC1 inhibitor bumetanide (BUM). Patients with FCD exhibited higher expression and internalized distribution of KCC2, particularly in the SOZ group. Conclusion: Our results provide evidence of a potential neurocircuit underpinning SOZ epileptogenesis and non-SOZ seizure susceptibility. Imbalanced function of NKCC1 and KCC2 may affect chloride ion homeostasis in neurons and alter GABAergic inhibitory action, thereby contributing to epileptogenesis in FCDs. Maintaining chloride ion homeostasis in the neurons may represent a new avenue for the development of novel anti-seizure medications (ASMs).

Meningeal carcinomatosis secondary to neurenteric cysts with malignant transformation: a case report.

BACKGROUND: Meningeal carcinomatosis is mainly associated with breast cancer, lung cancer, and melanoma. However, meningeal carcinomatosis secondary to a neurenteric cyst with malignant features is extremely rare. CASE PRESENTATION: We report the case of a 35-year-old woman who was admitted to the hospital with a 10-month history of headache, 6-month history of diplopia, 4-month history of hearing loss, and 1-month history of back pain, suggesting a diagnosis of chronic meningitis. Notably, enhanced brain and spinal cord magnetic resonance imaging (MRI) revealed extensive lesions with enhancement signals in the pia mater of the pons and cervical, thoracic, and lumbar spinal cord. The cerebral spinal fluid profile showed that pressure was significantly elevated, with a slight increase in leukocytes that mostly comprised mononuclear cells and decreased glucose concentration. Cytology evaluation showed a small cluster of atypical nuclei, which were suspected to be tumor cells arising from the epithelium. However, no primary tumor was found through comprehensive body and skin screening. After a histopathological biopsy of subarachnoid meninx of the thoracic spinal canal, the cause of meningeal carcinomatosis of this patient was determined as neurenteric cysts with malignant features, which is extremely rare. CONCLUSION: This is the first case to ever report neurenteric cysts as a cause of leptomeningeal carcinomatosis and the first ever report of neurenteric cysts presenting as leptomeningeal carcinomatosis without typical cyst visible on brain MRI. This extremely rare case provided a novel view on the pathogenesis of meningeal carcinomatosis and clinical presentation of neurenteric cysts, highlighting the value of meningeal biopsy in chronic meningitis of unknown causes.

Extremely Early-Onset Frontotemporal Dementia: A Case Report and Literature Review.

BACKGROUND: In most cases, the onset of frontotemporal dementia (FTD) occurs between the ages of 45 and 65 years. However, some patients experience an extremely early disease onset. OBJECTIVE: To investigate the clinical, genetic, and pathological features of extremely early-onset FTD. METHODS: We conducted a comprehensive clinical, genetic, and neuropathological analysis of a 25-year-old patient experiencing the onset of behavioral variant frontotemporal dementia (bvFTD). In addition, we conducted a literature review and summarized the clinical, genetic, and pathological features of patients with FTD with onset age≤25 years. RESULTS: The patient was diagnosed with bvFTD; however, there was no family history of FTD, no positive genetic test results and no deposition of TDP43, tau, ubiquitin, and synuclein in the brain. Literature screening identified 18 patients with onset age ≤25 years with FTD. The youngest patient was 14 years of age. Most patients (8/14) had a positive family history. The most common clinical phenotype was the behavioral variant (12/14). Genetic results were reported for 11 patients; the most common pathogenic gene was MAPT (10/12), with four cases of G389 R, two cases of P301 S, one case of G335 S, one case of G335A, one case of G335 V, and one case of L315 R. Pathological results were reported for 13 patients; the most common pathological subtype was tau (8/13). CONCLUSION: FTD can start at an extremely early age. The most common phenotype of extremely early onset FTD was the behavioral variant, the most common pathogenic gene was MAPT, and the most common neuropathological type was tau.

The ILAE consensus classification of focal cortical dysplasia: An update proposed by an ad hoc task force of the ILAE diagnostic methods commission.

Ongoing challenges in diagnosing focal cortical dysplasia (FCD) mandate continuous research and consensus agreement to improve disease definition and classification. An International League Against Epilepsy (ILAE) Task Force (TF) reviewed the FCD classification of 2011 to identify existing gaps and provide a timely update. The following methodology was applied to achieve this goal: a survey of published literature indexed with ((Focal Cortical Dysplasia) AND (epilepsy)) between 01/01/2012 and 06/30/2021 (n = 1349) in PubMed identified the knowledge gained since 2012 and new developments in the field. An online survey consulted the ILAE community about the current use of the FCD classification scheme with 367 people answering. The TF performed an iterative clinico-pathological and genetic agreement study to objectively measure the diagnostic gap in blood/brain samples from 22 patients suspicious for FCD and submitted to epilepsy surgery. The literature confirmed new molecular-genetic characterizations involving the mechanistic Target Of Rapamycin (mTOR) pathway in FCD type II (FCDII), and SLC35A2 in mild malformations of cortical development (mMCDs) with oligodendroglial hyperplasia (MOGHE). The electro-clinical-imaging phenotypes and surgical outcomes were better defined and validated for FCDII. Little new information was acquired on clinical, histopathological, or genetic characteristics of FCD type I (FCDI) and FCD type III (FCDIII). The survey identified mMCDs, FCDI, and genetic characterization as fields for improvement in an updated classification. Our iterative clinico-pathological and genetic agreement study confirmed the importance of immunohistochemical staining, neuroimaging, and genetic tests to improve the diagnostic yield. The TF proposes to include mMCDs, MOGHE, and "no definite FCD on histopathology" as new categories in the updated FCD classification. The histopathological classification can be further augmented by advanced neuroimaging and genetic studies to comprehensively diagnose FCD subtypes; these different levels should then be integrated into a multi-layered diagnostic scheme. This update may help to foster multidisciplinary efforts toward a better understanding of FCD and the development of novel targeted treatment options.

Progressive multifocal leukoencephalopathy in a patient with mediastinal teratoma: a case report.

BACKGROUND: Progressive multifocal leukoencephalopathy (PML) is a rare demyelinating lytic brain infection caused by the John Cunningham virus (JCV). JCV manifests primarily in patients with innate immunodeficiency or taking immunomodulatory medications. In this case study, we report a PML patient with comorbid mediastinal teratoma and mild lymphopenia. CASE PRESENTATION: A 73-year-old female presented with a 3-month history of progressive hemiplegia, hemianopsia, and cognitive impairment. She was diagnosed as PML by cerebrospinal fluid metagenomics sequencing and brain biopsy. Extensive immunological tests did not reveal an apparent immunodeficiency, but further work-up revealed that the PML was most likely the first presentation of mediastinal teratoma and the mild lymphopenia. Mirtazapine and immunoglobulin were started, the patient's condition was relatively stable and approved to be discharged from hospital. But unfortunately, she died of the lung infection 10 months after first presentation. CONCLUSIONS: This case confirms that mediastinal teratoma may induce the lymphopenia and trigger PML, delayed or incorrect diagnosis may worsen the course of the disease and result in poor prognosis.

Mechanistic Analysis of Micro-Neurocircuits Underlying the Epileptogenic Zone in Focal Cortical Dysplasia Patients.

We aim to explore the microscopic neurophysiology of focal cortical dysplasia (FCD) induced epileptogenesis in specific macroscopic brain regions, therefore mapping a micro-macro neuronal network that potentially indicates the epileptogenic mechanism. Epileptic and relatively non-epileptic temporal neocortex specimens were resected from FCD and mesial temporal lobe epilepsy (mTLE) patients, respectively. Whole-cell patch-clamping was performed on cells from the seizure onset zone (SOZ) and non-SOZ inside the epileptogenic zone (EZ) of FCD patients, as well as the non-epileptic neocortex of mTLE patients. Microscopic data were recorded, including membrane characteristics, spontaneous synaptic activities, and evoked action potentials. Immunohistochemistry was also performed on parvalbumin-positive (PV+) interneurons. We found that SOZ interneurons exhibited abnormal neuronal expression and distribution as well as reduced overall function compared with non-SOZ and mTLE interneurons. The SOZ pyramidal cells experienced higher excitation but lower inhibition than the mTLE controls, whereas the non-SOZ pyramidal cells exhibited intermediate excitability. Action potential properties of both types of neurons also suggested more synchronized neuronal activity inside the EZ, particularly inside the SOZ. Together, our research provides evidence for a potential neurocircuit underlying SOZ epileptogenesis and non-SOZ seizure susceptibility. Further investigation of this microscopic network may promote understanding of the mechanism of FCD-induced epileptogenesis.

Histone H3.3 G34-mutant Diffuse Gliomas in Adults.

The characteristics of H3.3 G34-mutant gliomas in adults have yet to be specifically described. Thirty adults with H3.3 G34-mutant diffuse gliomas were retrospectively reviewed for clinical and pathologic information. Molecular profiling using next-generation sequencing was performed in 29 of the 30 H3.3 G34-mutant patients with 1 patient lacking available tumor samples, as well as 82 IDH/H3 wild-type adult diffuse glioma patients. The age at diagnosis of H3.3 G34-mutant diffuse gliomas was significantly younger than IDH/H3 wild-type gliomas (24 vs. 57 y, P<0.001). Overall, 19 of the 30 patients were diagnosed of glioblastoma with the primitive neuronal component, and 8 were glioblastoma. The molecular profiling analysis revealed higher frequencies of Olig-2 loss of expression, TP53 mutation, ATRX mutation, PDGFRA mutation, and MGMT promoter methylation (P<0.05) in H3.3 G34-mutant gliomas than IDH/H3 wild-type gliomas. No TERT promoter mutation and only 1 case of EGFR amplification were detected in the H3.3 G34-mutant cohort, the frequencies of which were significantly higher in the IDH/H3 wild-type cohort. A dismal prognosis was observed in H3.3 G34-mutant patients comparing to IDH/H3 wild-type cohort (overall survival: 14 vs. 22 mo; P=0.026). Univariate and multivariate analyses showed that the extent of resection and TP53 mutation were independently affecting prognosis. The distinct pathologic and molecular features of H3.3 G34-mutant diffuse gliomas in adult patients demonstrated the clinical importance of detecting H3.3 G34R/V mutations. The dismal prognosis of this rare high-grade glioma disease we reported here would further promote the investigation of dedicated therapeutic strategies.

Integrated genotype-phenotype analysis of long-term epilepsy-associated ganglioglioma.

The BRAF p.V600E mutation is the most common genetic alteration in ganglioglioma (GG). Herein, we collected a consecutive series of 30 GG specimens from Xuanwu Hospital in order to corroborate the genetic landscape and genotype-phenotype correlation of this enigmatic and often difficult-to-classify epilepsy-associated brain tumor entity. All specimens with histopathologically confirmed lesions were submitted to targeted next-generation sequencing using a panel of 131 genes. Genetic alterations in three cases with histologically distinct tumor components, that is, GG plus pleomorphic xanthoastrocytoma (PXA), dysembryoplastic neuroepithelial tumor (DNT), or an oligodendroglioma (ODG)-like tumor component, were separately studied. A mean post-surgical follow-up time-period of 23 months was available in 24 patients. Seventy seven percent of GG in our series can be explained by genetic alterations, with BRAF p.V600E mutations being most prevalent (n = 20). Three additional cases showed KRAS p.Q22R and KRAS p.G13R, IRS2 copy number gain (CNG) and a KIAA1549-BRAF fusion. When genetically studying different histopathology patterns from the same tumor we identified composite features with BRAF p.V600E plus CDKN2A/B homozygous deletion in a GG with PXA features, IRS2 CNG in a GG with DNT features, and a BRAF p.V600E plus CNG of chromosome 7 in a GG with ODG-like features. Follow-up revealed no malignant tumor progression but nine patients had seizure recurrence. Eight of these nine GG were immunoreactive for CD34, six patients were male, five were BRAF wildtype, and atypical histopathology features were encountered in four patients, that is, ki-67 proliferation index above 5% or with PXA component. Our results strongly point to activation of the MAP kinase pathway in the vast majority of GG and their molecular-genetic differentiation from the cohort of low-grade pediatric type diffuse glioma remains, however, to be further clarified. In addition, histopathologically distinct tumor components accumulated different genetic alterations suggesting collision or composite glio-neuronal GG variants.

Dogs lacking Apolipoprotein E show advanced atherosclerosis leading to apparent clinical complications.

Atherosclerotic cardiovascular disease resulting from dysregulated lipid metabolism is the leading cause of morbidity and mortality worldwide. Apolipoprotein E (ApoE) plays a critical role in cholesterol metabolism. Knockouts in lipid-metabolizing proteins including ApoE in multiple model organisms such as mice and rats exhibiting elevated levels of cholesterol have been widely used for dissecting the pathology of atherosclerosis, but few of these animal models exhibit advanced atherosclerotic plaques leading to ischemia-induced clinical symptoms, limiting their use for translational studies. Here we report hypercholesterolemia and severe atherosclerosis characterized by stenosis and occlusion of arteries, together with clinical manifestations of stroke and gangrene, in ApoE knockout dogs generated by CRISPR/Cas9 and cloned by somatic cell nuclear transfer technologies. Importantly, the hypercholesterolemia and atherosclerotic complications in F0 mutants are recapitulated in their offspring. As the ApoE-associated atherosclerosis and clinical manifestations in mutant dogs are more similar to that in human patients compared with those in other animal models, these mutant dogs will be invaluable in developing and evaluating new therapies, including endovascular procedures, against atherosclerosis and related disorders.

Hartnup disease presenting as hereditary spastic paraplegia and severe peripheral neuropathy.

Hartnup disease cases were rare, and the genotype-phenotype correlation was not fully understood. Here we reported two unrelated young men diagnosed as Hartnup disease, who carried novel compound heterozygote mutations in the SLC6A19 gene and presented with new phenotypes. Other than intermittent encephalopathy and photosensitive rashes, they displayed symptoms and signs of spastic paraplegia and severe peripheral nerve damages. Magnetic resonance imaging showed mild bilateral cerebellar atrophy and thinning of the thoracic spinal cord. Electromyogram detected mixed sensorimotor polyneuropathy in lower limbs. Sural nerve biopsy and pathological study indicated the moderately reduced neural fibers in the periphery nerves. Urinary amino acid analysis showed increased levels of multiple neutral amino acids. Moreover, muscle strengths in the lower limbs and the walking ability have been improved in both cases (MRC 3/5 to 4/5 in Patient 1; walking distance elongated from 50 to 100 m in Patient 2) after the treatment with oral nicotinic acid and intravenous injection of multiple amino acids. Exome sequencing revealed and confirmed the existence of the novel compound heterozygous SLC6A19 mutations: c.533G>A (p.Arg178Gln) and c.1379-1G>C mutations in patient1, and c.1433delG (p.Gly478AlafsTer44) and c.811G>A (p.Ala271Thr) in patient 2. Taken together, these findings expanded the clinical, neuroimaging, pathology, and genetic spectrum of Hartnup disease. However, the co-existence of HSP and peripheral neuropathy was only inferred based on clinical observations, and pathological and molecular studies are needed to further dissect the underlying mechanisms.

Current Review of Leptomeningeal Amyloidosis Associated With Transthyretin Mutations.

INTRODUCTION: Leptomeningeal amyloidosis (LA) represents a rare subtype of familial transthyretin (TTR) amyloidosis, characterized by deposition of amyloid in cranial and spinal leptomeninges. Of >120 TTR mutations identified, few have been associated with LA. CASE REPORT: A 27-year-old male presented with a 2-year history of progressive symptoms including cognitive decline and right-sided weakness and numbness. Cerebrospinal fluid (CSF) analyses demonstrated high protein level. Gadolinium-enhanced magnetic resonance imaging (MRI) revealed extensive leptomeningeal enhancement over the surface of the brain and spinal cord. Pathologic analyses revealed a TTR mutation c.113A>G (p.D38G). REVIEW SUMMARY: Fifteen mutations and genotype-phenotype correlation of 72 LA patients have been summarized to provide an overview of LA associated with transthyretin mutations. The mean age of clinical onset was 44.9 years and the neurological symptoms primarily included cognitive impairment, headache, ataxia seizures and hearing, visual loss. CSF analysis showed elevated high CSF protein level and MRI revealed extensive leptomeningeal enhancement. CONCLUSION: Clinicians should be aware of this rare form of familial transthyretin amyloidosis as well as its typical MRI enhancement and high CSF protein. The important role of biopsy, genetic testing and the potential early diagnosis value of contrast MRI were suggested. Early recognition of these characteristics is important to provide misdiagnosis and shorten the time before correct diagnosis. These findings expand the phenotypic spectrum of TTR gene and have implications for the diagnosis, treatment, and systematic study of LA.

Concomitant KIAA1549-BRAF fusion and IDH mutation in Pediatric spinal cord astrocytoma: a case report and literature review.

Primary tumors of the spinal cord are rare, accounting for 3-6% of tumors in the central nervous system, particularly in children. KIAA1549-BRAF fusion is more common in pilocytic astrocytoma (PA) and IDH1 R132H mutation is rare in infratentorial tumors. Here, we report a 10-year-old male patient who presented with weakness in lower limbs that progressed to difficulty walking. Magnetic resonance imaging (MRI) revealed an intramedullary solid-cystic lesion from the medulla oblongata to the thoracic spin 4 level, with the expansion of the spinal cord. The lesion exhibited patchy enhancement at C4-T1, indicating a tentative diagnosis of astrocytoma. The patient underwent resection of the lesion in the spinal canal from the cervical 6 level to the thoracic 2 level. Histopathology confirmed diagnosis of astrocytoma, WHO grade 2. Genetic analysis showed both IDH1 R132H mutation and KIAA1549-BRAF fusion. Therefore, our integrated diagnosis was astrocytoma, IDH mutation, WHO grade 2. Its molecular analyses include IDH1 R132H mutation and KIAA1549-BRAF fusion. After the operation, the patient did not receive chemo- or radiotherapy, and underwent an aggressive rehabilitation regiment. Follow up 10 months later, symptoms improved. To our best knowledge, this is the first case of concomitant IDH mutation and BRAF fusion in pediatric spinal cord astrocytoma.

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.

An adult case of diffuse midline glioma with H3 K27M mutation.

Cartilaginous metaplasia is rare in primary central nervous system (CNS) neoplasms and has not been described in the histone 3 (H3) gene (H3) with a substitution of lysine to methionine (H3 K27M mutant) diffuse midline glioma before. Here, we report a case of H3 K27M mutant diffuse midline glioma with cartilaginous metaplasia in a 56-year-old woman. Magnetic resonance imaging (MRI) revealed a ring-enhanced lesion located in the medulla oblongata and extended superiorly into the fourth ventricle. The tumor was macroscopically completely resected. Histologically, the tumor was composed of a gliomatous component and a well-differentiated cartilaginous component. Microvascular proliferation and necrosis were noted. According to immunohistochemical staining, glial cells were diffusely and strongly positive for glial fibrillary acidic protein (GFAP), oligodendrocyte lineage transcription factor 2 (Olig2), H3 K27M, and S-100 protein but negative for H3K27me3. The chondrocytes also were positive for GFAP and S-100 protein. The H3 K27M mutation was confirmed by sequencing in both the gliomatous and cartilaginous components, suggesting a common origin from the same progenitor cells. Based on these findings, the tumor was diagnosed as a diffuse midline glioma with H3 K27M mutation with widespread cartilaginous metaplasia, corresponding to WHO grade IV. This is an extremely rare H3 K27M mutant diffuse midline glioma with cartilaginous metaplasia, and reporting this unusual case adds to the understanding of this tumor type.