Primary cauda equina lymphoma confirmed by autopsy: A case report

Compared with those involving the central nervous system, lymphomas involving the peripheral nervous system, namely neurolymphomatosis, are extremely rare. Neurolymphomatosis is classified as primary or secondary; the former is much rarer than the latter. Herein, we present an autopsied case of primary cauda equina lymphoma (PCEL), a type of primary neurolymphomatosis, with a literature review of autopsied cases of PCEL as well as primary neurolymphomatosis other than PCEL (non-PCEL primary neurolymphomatosis). A 70-year-old woman presented with difficulty walking, followed by paraplegia and then bladder and bowel disturbance. On magnetic resonance imaging, the cauda equina was diffusely enlarged and enhanced with gadolinium. The brainstem and cerebellum were also enhanced with gadolinium along their surface. The differential diagnosis of the patient included meningeal tumors (other than lymphomas), lymphomas, or sarcoidosis. The biopsy of the cauda equina was planned for a definite diagnosis, but because the patient deteriorated so rapidly, it was not performed. Eventually, she was affected by cranial nerve palsies. With the definite diagnosis being undetermined, the patient died approximately 1.5 years after the onset of disesase. At autopsy, the cauda equina was replaced by a bulky mass composed of atypical B-lymphoid cells, consistent with diffuse large B-cell lymphoma (DLBCL). The spinal cord was heavily infiltrated, as were the spinal/cranial nerves and subarachnoid space. There was metastasis in the left adrenal. The patient was finally diagnosed postmortem as PCEL with a DLBCL phenotype. To date, there have been a limited number of autopsied cases of PCEL and non-PCEL primary neurolymphomatosis (nine cases in all, including ours). The diagnosis is, without exception, B-cell lymphoma including DLBCL, and the histology features central nervous system parenchymal infiltration, nerve root involvement, and subarachnoid dissemination (lymphomatous meningitis). Metastases are not uncommon. All clinicians and pathologists should be aware of lymphomas primarily involving the peripheral nervous system.

The predominance of "astrocytic" intranuclear inclusions in neuronal intranuclear inclusion disease manifesting encephalopathy-like symptoms: A case series with brain biopsy

Neuronal intranuclear inclusion disease (NIID) is a neurodegenerative disorder represented by eosinophilic intranuclear inclusions (EIIs) and GGC/CGG repeat expansion in the NOTCH2NLC gene. We report here two adult cases of NIID, genetically confirmed, with manifestation of encephalopathy-like symptoms and address the histopathologic findings obtained by brain biopsies, with a focus on "astrocytic" intranuclear inclusions (AIIs). Case 1 presented with paroxysmal restlessness, vertigo, or fever and was later involved in severe dementia and tetraparesis. Case 2 presented with forgetfulness and then with paroxysmal fever and headache. In both cases, delimited areas with gadolinium enhancement on magnetic resonance imaging and corresponding hyperperfusion were detected, leading to brain biopsies of the cortex. On histology, Case 1 showed an abnormal lamination, where the thickness of layers was different from usual. Both neurons and astrocytes showed some dysmorphologic features. Notably, astrocytes rather than neurons harbored EIIs. Case 2 showed a cortex, where neurons tended to be arrayed in a columnar fashion. Astrocytes showed some dysmorphologic features. Notably, much more astrocytes than neurons harbored EIIs. By a double-labeling immunofluorescence study for p62/NeuN and p62/glial fibrillary acidic protein, the predominance of AIIs was confirmed in both cases. Considering the physiological functions of astrocytes for the development and maintenance of the cortex, the encephalopathy-like symptoms, dynamic change of cerebral blood flow, and cortical dysmorphology can reasonably be explained by the dysfunction of EII-bearing astrocytes rather than EII-bearing neurons. This study suggests the presence of a subtype of NIID where AIIs rather than "neuronal" intranuclear inclusions are likely a key player in the pathogenesis of NIID, particularly in cases with encephalopathy-like symptoms. The importance of AIIs ("gliopathy") should be more appreciated in future studies of NIID.

DNA hypomethylator phenotype reprograms glutamatergic network in receptor tyrosine kinase gene-mutated glioblastoma

DNA methylation is crucial for chromatin structure and gene expression and its aberrancies, including the global "hypomethylator phenotype", are associated with cancer. Here we show that an underlying mechanism for this phenotype in the large proportion of the highly lethal brain tumor glioblastoma (GBM) carrying receptor tyrosine kinase gene mutations, involves the mechanistic target of rapamycin complex 2 (mTORC2), that is critical for growth factor signaling. In this scenario, mTORC2 suppresses the expression of the de novo DNA methyltransferase (DNMT3A) thereby inducing genome-wide DNA hypomethylation. Mechanistically, mTORC2 facilitates a redistribution of EZH2 histone methyltransferase into the promoter region of DNMT3A, and epigenetically represses the expression of DNA methyltransferase. Integrated analyses in both orthotopic mouse models and clinical GBM samples indicate that the DNA hypomethylator phenotype consistently reprograms a glutamate metabolism network, eventually driving GBM cell invasion and survival. These results nominate mTORC2 as a novel regulator of DNA hypomethylation in cancer and an exploitable target against cancer-promoting epigenetics.

Granulocyte macrophage colony-stimulating factor-induced macrophages of individuals with autism spectrum disorder adversely affect neuronal dendrites through the secretion of pro-inflammatory cytokines

BACKGROUND

A growing body of evidence suggests that immune dysfunction and inflammation in the peripheral tissues as well as the central nervous system are associated with the neurodevelopmental deficits observed in autism spectrum disorder (ASD). Elevated expression of pro-inflammatory cytokines in the plasma, serum, and peripheral blood mononuclear cells of ASD has been reported. These cytokine expression levels are associated with the severity of behavioral impairments and symptoms in ASD. In a prior study, our group reported that tumor necrosis factor-α (TNF-α) expression in granulocyte-macrophage colony-stimulating factor-induced macrophages (GM-CSF MΦ) and the TNF-α expression ratio in GM-CSF MΦ/M-CSF MΦ (macrophage colony-stimulating factor-induced macrophages) was markedly higher in individuals with ASD than in typically developed (TD) individuals. However, the mechanisms of how the macrophages and the highly expressed cytokines affect neurons remain to be addressed.

METHODS

To elucidate the effect of macrophages on human neurons, we used a co-culture system of control human-induced pluripotent stem cell-derived neurons and differentiated macrophages obtained from the peripheral blood mononuclear cells of five TD individuals and five individuals with ASD. All participants were male and ethnically Japanese.

RESULTS

Our results of co-culture experiments showed that GM-CSF MΦ affect the dendritic outgrowth of neurons through the secretion of pro-inflammatory cytokines, interleukin-1α and TNF-α. Macrophages derived from individuals with ASD exerted more severe effects than those derived from TD individuals.

LIMITATIONS

The main limitations of our study were the small sample size with a gender bias toward males, the use of artificially polarized macrophages, and the inability to directly observe the interaction between neurons and macrophages from the same individuals.

CONCLUSIONS

Our co-culture system revealed the non-cell autonomous adverse effects of GM-CSF MΦ in individuals with ASD on neurons, mediated by interleukin-1α and TNF-α. These results may support the immune dysfunction hypothesis of ASD, providing new insights into its pathology.

Transcriptomic and epigenetic dissection of spinal ependymoma (SP-EPN) identifies clinically relevant subtypes enriched for tumors with and without NF2 mutation

Ependymomas encompass multiple clinically relevant tumor types based on localization and molecular profiles. Tumors of the methylation class "spinal ependymoma" (SP-EPN) represent the most common intramedullary neoplasms in children and adults. However, their developmental origin is ill-defined, molecular data are scarce, and the potential heterogeneity within SP-EPN remains unexplored. The only known recurrent genetic events in SP-EPN are loss of chromosome 22q and NF2 mutations, but neither types and frequency of these alterations nor their clinical relevance have been described in a large, epigenetically defined series. Transcriptomic (n = 72), epigenetic (n = 225), genetic (n = 134), and clinical data (n = 112) were integrated for a detailed molecular overview on SP-EPN. Additionally, we mapped SP-EPN transcriptomes to developmental atlases of the developing and adult spinal cord to uncover potential developmental origins of these tumors. The integration of transcriptomic ependymoma data with single-cell atlases of the spinal cord revealed that SP-EPN display the highest similarities to mature adult ependymal cells. Unsupervised hierarchical clustering of transcriptomic data together with integrated analysis of methylation profiles identified two molecular SP-EPN subtypes. Subtype A tumors primarily carried previously known germline or sporadic NF2 mutations together with 22q loss (bi-allelic NF2 loss), resulting in decreased NF2 expression. Furthermore, they more often presented as multilocular disease and demonstrated a significantly reduced progression-free survival as compared to SP-EP subtype B. In contrast, subtype B predominantly contained samples without NF2 mutation detected in sequencing together with 22q loss (monoallelic NF2 loss). These tumors showed regular NF2 expression but more extensive global copy number alterations. Based on integrated molecular profiling of a large multi-center cohort, we identified two distinct SP-EPN subtypes with important implications for genetic counseling, patient surveillance, and drug development priorities.

Brain-derived neurotrophic factor from microglia regulates neuronal development in the medial prefrontal cortex and its associated social behavior

Microglia and brain-derived neurotrophic factor (BDNF) are essential for the neuroplasticity that characterizes critical developmental periods. The experience-dependent development of social behaviors-associated with the medial prefrontal cortex (mPFC)-has a critical period during the juvenile period in mice. However, whether microglia and BDNF affect social development remains unclear. Herein, we aimed to elucidate the effects of microglia-derived BDNF on social behaviors and mPFC development. Mice that underwent social isolation during p21-p35 had increased Bdnf in the microglia accompanied by reduced adulthood sociability. Additionally, transgenic mice overexpressing microglial Bdnf-regulated using doxycycline at different time points-underwent behavioral, electrophysiological, and gene expression analyses. In these mice, long-term overexpression of microglial BDNF impaired sociability and excessive mPFC inhibitory neuronal circuit activity. However, administering doxycycline to normalize BDNF from p21 normalized sociability and electrophysiological function in the mPFC, whereas normalizing BDNF from later ages (p45-p50) did not normalize electrophysiological abnormalities in the mPFC, despite the improved sociability. To evaluate the possible role of BDNF in human sociability, we analyzed the relationship between adverse childhood experiences and BDNF expression in human macrophages, a possible proxy for microglia. Results show that adverse childhood experiences positively correlated with BDNF expression in M2 but not M1 macrophages. In summary, our study demonstrated the influence of microglial BDNF on the development of experience-dependent social behaviors in mice, emphasizing its specific impact on the maturation of mPFC function, particularly during the juvenile period. Furthermore, our results propose a translational implication by suggesting a potential link between BDNF secretion from macrophages and childhood experiences in humans.

Somatosensory pathway dysfunction in patients with amyotrophic lateral sclerosis in a completely locked-in state

OBJECTIVE

To investigate somatosensory pathway function in patients with amyotrophic lateral sclerosis (ALS) dependent on invasive ventilation and in a completely locked-in state (CLIS).

METHODS

We examined median nerve somatosensory evoked potentials (SEPs) in 17 ALS patients in a CLIS, including 11 patients with sporadic ALS, one with familial ALS with genes not examined, four with a Cu/Zn superoxide-dismutase-1 (SOD1) gene variant (Val118Leu, Gly93Ser, Cys146Arg), and one with a fused-in-sarcoma gene variant (P525L). We evaluated N9, N13, N20 and P25, and central conduction time (CCT); the data were compared with those of 73 healthy controls.

RESULTS

N20 and N13 were abolished in 12 and 10 patients, and their latencies was prolonged in four and three patients, respectively. The CCT was prolonged in five patients with measurable N13 and N20. Two patients with SOD1 gene mutations had absent or slightly visible N9. Compared to the CCT and latencies and amplitudes of N13 and N20 in the controls, those in the patient cohort were significantly abnormal.

CONCLUSIONS

The central somatosensory pathway is severely involved in patients with ALS in a CLIS.

SIGNIFICANCE

Our findings suggest that median nerve SEP cannot be utilized for communication in patients with ALS in a CLIS.

Genetic alterations that deregulate RB and PDGFRA signaling pathways drive tumor progression in IDH2-mutant astrocytoma

In IDH-mutant astrocytoma, IDH2 mutation is quite rare and biological mechanisms underlying tumor progression in IDH2-mutant astrocytoma remain elusive. Here, we report a unique case of IDH2 mutant astrocytoma, CNS WHO grade 3 that developed tumor progression. We performed a comprehensive genomic and epigenomic analysis for primary and recurrent tumors and found that both tumors harbored recurrent IDH2R172K and TP53R248W mutation with CDKN2A/B hemizygous deletion. We also found amplifications of CDK4 and MDM2 with PDGFRA gain in the recurrent tumor and upregulated protein expressions of these genes. We further developed, for the first time, a xenograft mouse model of IDH2R172K and TP53R248W mutant astrocytoma from the recurrent tumor, but not from the primary tumor. Consistent with parent recurrent tumor cells, amplifications of CDK4 and MDM2 and PDGFRA gain were found, while CDKN2A/B was identified as homozygous deletion in the xenografts, qualifying for integrated diagnosis of astrocytoma, IDH2-mutant, CNS WHO grade 4. Cell viability assay found that CDK4/6 inhibitor and PDGFR inhibitor potently decreased cell viability in recurrent tumor cells, as compared to primary tumor cells. These findings suggest that gene alterations that activate retinoblastoma (RB) signaling pathways and PDGFR may drive tumor progression and xenograft formation in IDH2-mutant astrocytoma, which is equivalent to progressive IDH1-mutant astrocytoma. Also, our findings suggest that these genomic alterations may represent therapeutic targets in IDH2-mutant astrocytoma.

Clinical course of pathologically confirmed corticobasal degeneration and corticobasal syndrome

The clinical presentation of corticobasal degeneration is diverse, while the background pathology of corticobasal syndrome is also heterogeneous. Therefore, predicting the pathological background of corticobasal syndrome is extremely difficult. Herein, we investigated the clinical findings and course in patients with pathologically, genetically and biochemically verified corticobasal degeneration and corticobasal syndrome with background pathology to determine findings suggestive of background disorder. Thirty-two patients were identified as having corticobasal degeneration. The median intervals from the initial symptoms to the onset of key milestones were as follows: gait disturbance, 0.0 year; behavioural changes, 1.0 year; falls, 2.0 years; cognitive impairment, 2.0 years; speech impairment, 2.5 years; supranuclear gaze palsy, 3.0 years; urinary incontinence, 3.0 years; and dysphagia, 5.0 years. The median survival time was 7.0 years; 50% of corticobasal degeneration was diagnosed as corticobasal degeneration/corticobasal syndrome at the final presentation. Background pathologies of corticobasal syndrome (n = 48) included corticobasal degeneration (33.3%), progressive supranuclear palsy (29.2%) and Alzheimer's disease (12.5%). The common course of corticobasal syndrome was initial gait disturbance and early fall. In addition, corticobasal degeneration-corticobasal syndrome manifested behavioural change (2.5 years) and cognitive impairment (3.0 years), as the patient with progressive supranuclear palsy-corticobasal syndrome developed speech impairment (1.0 years) and supranuclear gaze palsy (6.0 years). The Alzheimer's disease-corticobasal syndrome patients showed cognitive impairment (1.0 years). The frequency of frozen gait at onset was higher in the corticobasal degeneration-corticobasal syndrome group than in the progressive supranuclear palsy-corticobasal syndrome group [P = 0.005, odds ratio (95% confidence interval): 31.67 (1.46-685.34)]. Dysarthria at presentation was higher in progressive supranuclear palsy-corticobasal syndrome than in corticobasal degeneration-corticobasal syndrome [P = 0.047, 6.75 (1.16-39.20)]. Pyramidal sign at presentation and personality change during the entire course were higher in Alzheimer's disease-corticobasal syndrome than in progressive supranuclear palsy-corticobasal syndrome [P = 0.011, 27.44 (1.25-601.61), and P = 0.013, 40.00 (1.98-807.14), respectively]. In corticobasal syndrome, decision tree analysis revealed that 'freezing at onset' or 'no dysarthria at presentation and age at onset under 66 years in the case without freezing at onset' predicted corticobasal degeneration pathology with a sensitivity of 81.3% and specificity of 84.4%. 'Dysarthria at presentation and age at onset over 61 years' suggested progressive supranuclear palsy pathology, and 'pyramidal sign at presentation and personality change during the entire course' implied Alzheimer's disease pathology. In conclusion, frozen gait at onset, dysarthria, personality change and pyramidal signs may be useful clinical signs for predicting background pathologies in corticobasal syndrome.

Systemic Metastasis of Pediatric Diffuse High-grade Astrocytoma: A Case Report

Extracranial brain tumor metastases are extremely rare. The etiology, pathophysiology, and clinical progression of systemic metastatic brain cancer remain to be elucidated. We encountered a case of pediatric diffuse high-grade astrocytoma in a four-year-old girl with subcutaneous and lymph node metastases. Numerous metastatic lesions emerged, progressed rapidly, and were difficult to manage despite temozolomide (TMZ) administration. The patient underwent repeated surgical resection for these lesions. Conversely, the primary intracranial lesions responded well to TMZ for some time. However, the patient died 15 months after the initial diagnosis. Extracranial metastasis and highly varying effects of chemotherapy were the characteristic clinical features in this case. Our analysis did not reveal definitive histopathological and molecular factors contributing to this presentation. The lack of notable molecular pathological features illustrates the unpredictability of glioma metastasis, and the treatment for extracranial metastasis remains unknown. A gene panel analysis revealed several genetic aberrations, including PDGFRA, PIK3CA, and NBN mutations. As it is impossible to resect all frequently and rapidly progressing lesions, we stress that the prognosis of metastatic brain tumors is undoubtedly poor if these tumors are refractory to existing treatments, including chemotherapy.

Expanded ischemic lesion due to herniation leads to axonal injury in a site remote to the primary lesion on autopsy brain with acute focal cerebral ischemia

Cerebral ischemia may lead to axonal injury not only at the site of the primary lesion but also in a region remote to the site of insult. In this study, we investigated the effect of herniation on the development of axonal injury at a site remote to the primary lesion during the acute phase of cerebral ischemia. We obtained postmortem brains of 13 cases with acute phase of unilateral cerebral infarction in the territory of the internal carotid artery or middle cerebral artery and seven controls. We classified the brain tissues into herniation and non-herniation groups. Then we examined whether axonal and ischemic changes existed in the corpus callosum contralateral to the ischemic hemisphere and the upper pons. In the herniation group, we detected white-matter lesions by Klüver-Barrera staining, microglial loss by immunohistochemistry for ionized calcium-binding adaptor molecule 1, and axonal injury by immunohistochemistry for amyloid precursor protein. However, none of the aforementioned findings were observed in the non-herniation group. These findings suggest the existence of regional overlap in axonal and ischemic pathologies in remote regions in the presence of herniation. We concluded that herniation may play a significant role in the development of axonal and ischemic changes in the remote region. Our results suggest that axonal injury in a remote region may result from expanded ischemic lesions due to herniation.

Altered properties of amyloidogenic prion protein in genetic Creutzfeldt-Jakob disease with PRNP V180I mutation in response to pentosan polysulfate

Genetic Creutzfeldt-Jakob disease (gCJD) with V180I prion protein gene (PRNP) mutation shows weaker prion protein (PrP) deposition histologically compared with sporadic CJD, and it is more difficult to detect protease-resistant prion protein in immunoblotting. However, we previously reported the autopsy case of a patient with V180I gCJD who was treated with pentosan polysulfate sodium (PPS); this case had increased protease-resistant PrP deposition. It has been suggested that PPS might reduce protease-resistant PrP; however, the detailed pharmacological and histopathological effects of PPS in humans remain unknown. We examined autopsied human brain tissue from four cases with V180I gCJD that were added to our archives between 2011 and 2021: two cases treated with PPS and two cases without PPS. We conducted a neuropathological assessment, including immunohistochemistry for PrP. We also performed immunoblotting for PrP on homogenate samples from each brain to detect protease-resistant PrP using both a conventional procedure and size-exclusion gel chromatography for the purification of oligomeric PrP. Both PPS-treated cases showed long survival time over 5 years from onset and increased PrP deposition with a characteristic pattern of coarse granular depositions and congophilic PrP microspheres, whereas the cases without PPS showed around 1-year survival from onset and relatively mild neuronal loss and synaptic PrP deposition. Although cortical gliosis seemed similar among all cases, aquaporin 4-expression as a hallmark of astrocytic function was increased predominantly in PPS cases. Immunoblotting of non-PPS cases revealed protease-resistant PrP in the oligomeric fraction only, whereas the PPS-treated cases showed clear signals using conventional procedures and in the oligomeric fraction. These unique biochemical and histopathological changes may reflect the progression of V180I gCJD and its modification by PPS, suggesting the possible existence of toxic PrP-oligomer in the pathophysiology of V180I gCJD and beneficial effects of PPS toward the aggregation and detoxication of toxic PrP-oligomer.

Disease specific brain capillary angiopathy in schizophrenia, bipolar disorder, and Alzheimer's disease

Schizophrenia (SZ) and bipolar disorder (BD), which are both psychiatric disorders, share some common clinical evidence. We recently discovered that brain capillary angiopathy is another common feature of these psychiatric disorders using fibrin accumulation in vascular endothelial cells as an indicator. This study aimed to characterize the similarities and differences in cerebral capillary injuries in various brain diseases to provide new diagnostic methods for SZ and BD and to develop new therapeutic strategies. We evaluated whether discrepancies exist in the degree of vascular damage among SZ and BD and other brain disorders (amyotrophic lateral sclerosis (ALS), Parkinson's disease (PD), and Alzheimer's disease (AD)) using postmortem brains. Our results demonstrate that fibrin was strongly accumulated in the capillaries of the grey matter (GM) of brains of patients with SZ and AD and in the capillaries of the white matter (WM) in those of patients with SZ, BD, and AD when compared with control subjects without any psychiatric or neurological disease history. However, ALS and PD brains did not present a significant increase in the amount of accumulated fibrin, either in the capillaries of WM or GM. Furthermore, significant leakage of fibrin into the brain parenchyma, indicating a vascular physical disruption, was observed in the brains of patients with AD but not in the brains of other patients compared with control subjects. In conclusion, our work reveals that Fibrin-accumulation in the brain capillaries are observed in psychiatric disorders, such as SZ, BD, and AD. Furthermore, fibrin-accumulating, nonbreaking type angiopathy is characteristic of SZ and BD, even though there are regional differences between these diseases.

Brain-derived neurotrophic factor from microglia regulates neuronal development in the medial prefrontal cortex and its associated social behavior

Microglia and brain-derived neurotrophic factor (BDNF) are essential for the neuroplasticity that characterizes critical developmental periods. The experience-dependent development of social behaviors-associated with the medial prefrontal cortex (mPFC)-has a critical period during the juvenile period in mice. However, whether microglia and BDNF affect social development remains unclear. Herein, we aimed to elucidate the effects of microglia-derived BDNF on social behaviors and mPFC development. Mice that underwent social isolation during p21-p35 had increased Bdnf in the microglia accompanied by reduced adulthood sociability. Additionally, transgenic mice overexpressing microglia Bdnf-regulated using doxycycline at different time points-underwent behavioral, electrophysiological, and gene expression analyses. In these mice, long-term overexpression of microglia BDNF impaired sociability and excessive mPFC inhibitory neuronal circuit activity. However, administration of doxycycline to normalize BDNF from p21 normalized sociability and electrophysiological functions; this was not observed when BDNF was normalized from a later age (p45-p50). To evaluate the possible role of BDNF in human sociability, we analyzed the relationship between adverse childhood experiences and BDNF expression in human macrophages, a possible substitute for microglia. Results show that adverse childhood experiences positively correlated with BDNF expression in M2 but not M1 macrophages. Thus, microglia BDNF might regulate sociability and mPFC maturation in mice during the juvenile period. Furthermore, childhood experiences in humans may be related to BDNF secretion from macrophages.

Differential immunophenotypes of neuronal cytoplasmic inclusions in the dentate gyrus of multiple system atrophy and their association with clinicopathological features

Although hippocampal pathologies of multiple system atrophy (MSA) and their association with dementia have been reported, no studies have reported clinicopathological differences among MSA patients with and without neuronal cytoplasmic inclusions (NCIs) in the dentate gyrus (dntNCIs). We investigated hippocampal NCI pathology in 18 MSA patient autopsies, focusing on phosphorylated α-synuclein (pAS)- and phosphorylated tau (pT)-positive dntNCIs. There were 8 MSA patients without and 10 with dntNCIs. The latter group was subclassified by immunophenotype: those with pAS-positive dntNCIs (pAS-dntNCI subtype), those with pT-positive dntNCIs (pT-dntNCI subtype), and those with both types of dntNCIs. MSA patients with dntNCIs survived longer with prolonged tracheostomy and had dementia more frequently than those without dntNCIs. The brain weights of patients with dntNCIs were lower than those without dntNCIs. The presence of dementia was similar among the dntNCI subtypes. The pAS-dntNCI subtype was associated with longer survival and smaller brain weights; the pT-dntNCI subtype exhibited more frequent tau pathologies than the pAS-dntNCI subtype. Thus, MSA with dntNCIs is a possible pathological subtype of longer survivors that correlates with longer disease duration, prolonged tracheostomy, and high frequency of dementia. Understanding clinicopathological differences in MSA patients with and without dntNCIs may lead to improved personalized management strategies.

Neuropathological features of adult-onset neuronal intranuclear inclusion disease with fluid-attenuated inversion recovery high-intensity signals in the cerebellar paravermal area from an early stage: A case report

Neuronal intranuclear inclusion disease (NIID) is a neurological disorder characterized by eosinophilic intranuclear inclusions (INI) in systemic organs and various cell types. High-intensity signals along the corticomedullary junction on diffusion-weighted imaging and presence of cellular p62-INI in skin biopsy are known indicators for NIID. Furthermore, GGC repeat expansion in NOTCH2NLC is a characteristic genetic alteration in patients with NIID. This report presents the clinical and detailed pathological features of a male older adult with NIID. We also confirmed the presence of fluid-attenuated inversion recovery high-intensity signals in the cerebellar paravermal area, showing similar pathological changes in high-intensity signals along the corticomedullary junction on diffusion-weighted imaging.

An Autopsy Case of Elderly Onset Brainstem Acute Disseminated Encephalomyelitis

Acute disseminated encephalomyelitis (ADEM), which is a disease that causes multifocal inflammatory demyelination of the central nervous system, occurs predominantly in children and young adults. We report an autopsy case of an elderly man with brainstem ADEM that progressed over a period of about 3 months. An 82-year-old man developed disturbance of consciousness, dysphagia, and ataxic gait over a period of about 3 months. He was admitted to another hospital for aspiration pneumonia and recovered but was transferred to our hospital due to prolonged disturbance of consciousness. The patient was able to follow simple commands but had a tendency to somnolence. In addition to meningeal stimulation signs, the patient had left-dominant upper and lower limb ataxia and right-dominant limb spasticity. Brain FLAIR/T2-weighted imaging showed high-intensity lesions from the brainstem to the middle cerebellar peduncle bilaterally, medulla oblongata and upper cervical spinal cord, and T1-weighted imaging revealed contrast-enhanced lesions in the left middle cerebellar peduncle and cervical spinal cord. Although spinal fluid examination revealed elevated proteins, other laboratory tests indicated no evidence of infection, vasculitis, collagen diseases or tumors, and anti-ganglioside, anti-AQP4 and anti-MOG antibodies were negative. After admission, the patient again developed aspiration pneumonia, which progressed to acute respiratory distress syndrome, and he died on the 15th day of hospitalization. Autopsy findings indicated acute and subacute demyelination mainly in the brainstem and cerebellum, and perivascular lymphocyte and macrophage infiltration in the areas of demyelination. A postmortem diagnosis of ADEM was made based on the generally monophasic course of the disease and the absence of regenerating myelinated sheaths. There are very few reports of elderly patients with brainstem ADEM. ADEM should be considered as a differential diagnosis in patients with brainstem encephalitis.

A multicenter, randomized, placebo-controlled phase IIb trial of an autologous formalin-fixed tumor vaccine for newly diagnosed glioblastomas

OBJECTIVE

An autologous formalin-fixed tumor vaccine (AFTV) derived from resected glioblastoma (GBM) tissue can be used against unidentified tumor antigens. Thus, the authors conducted a multicenter double-blind phase IIb trial to investigate the efficacy of an AFTV.

METHODS

Eligible patients were adults with supratentorial GBMs, 16-75 years of age, with Karnofsky Performance Scale (KPS) scores ≥ 60%, and no long-term steroid administration. An AFTV comprising fixed paraffin-embedded tumor tissue with immune adjuvants or an identical placebo without fixed tumor tissue was injected intradermally over three courses before and after chemoradiotherapy. The primary and secondary end points were overall survival (OS), progression-free survival (PFS), and 3-year survival rate.

RESULTS

Sixty-three patients were enrolled. The average patient age was 61 years. The median KPS score was 80%, and the median resection rate was 95%. The full analysis set of 57 patients indicated no significant difference in OS (p = 0.64) for the AFTV group (median OS 25.6 months, 3-year OS rate 38%) compared with the placebo group (31.5 months and 41%, respectively) and no difference in PFS (median PFS 13.3 months in both groups, p = 0.98). For patients with imaging-based total tumor removal, the 3-year PFS rate was 81% in the AFTV group versus 46% in the placebo group (p = 0.067), whereas the 3-year OS rate was 80% versus 54% (p = 0.16), respectively. Similar results were obtained in the p53-negative subgroups. Severe adverse effects were not observed.

CONCLUSIONS

The AFTV may have potential effects in certain patient subgroups. A phase III study for patients with total tumor removal remains warranted to confirm these findings. Clinical trial registration no.: UMIN000010602 (UMIN Clinical Trials Registry).

Synthesis, Structures, and Complexation with Phenolic Guests of Acridone-Incorporated Arylene-Ethynylene Macrocyclic Compounds

Acridone units were incorporated into the arylene-ethynylene structure as polar arene units. Cyclic trimers consisting of three acridone-2,7-diyl units and three 1,3-phenylene units were synthesized by Sonogashira couplings via stepwise or direct route. X-ray analysis revealed that the trimer had a nearly planar macrocyclic framework with a cavity surrounded by three carbonyl groups. In contrast, the corresponding tetramer had a nonplanar macrocyclic framework. ¹ H NMR measurements showed that the trimer formed a 1 : 1 complex as a macrocyclic host with dihydric phenol guests, and the association constants were determined to be ca. 1.0×10³  L mol^-1 for hydroquinone or resorcinol guests in CDCl₃ at 298 K. The calculated structures of these complexes by the DFT method supported the presence of two sets of OH⋅⋅⋅O=C hydrogen bonds between the host and guest molecules. The spectroscopic data of the cyclic trimers and tetramers are compared with those of reference acridone compounds.

MPC-10 RECURRENT ASTROCYTOMA WITH SOMATIC IDH MOSAICISM: A CASE REPORT AND WARRANT FOR MOLECULAR DIAGNOSTICS

Introduction

Acquisition of somatic mutations is essential for the development of malignant tumors such as diffuse gliomas. Recent single-cell analyses have pointed out the importance of somatic mosaicism in the pathogenesis of cancer. Here we report a case of IDH (isocitrate dehydrogenase)-mutant astrocytoma that has relapsed after intensive chemoradiation with somatic mosaicism for the IDH1 R132H mutation.

Clinical and Pathological Findings

A 36-year-old male presented with epileptic symptoms and a mass lesion in the right frontal lobe. A needle biopsy demonstrated IDH-mutant astrocytoma (grade 2). At the age of 41, relapsed tumor was completely resected, and the tumor cells were diffusely positive for IDH1 R132H with grade 4 morphology. Chemoradiotherapy (PAV + IMRT 60Gy/30fr) was added, but contrast-enhanced lesions reappeared 5 months after the initial surgery. The re-excised specimen was grade 4 astrocytoma, and the number of IDH1 R132H-positive tumor cells was very small compared to the total number of tumor cells, suggesting somatic mosaicism for IDH mutations.

Conclusion

It is imperative to clarify the induction mechanism and significance of somatic cell mosaicism in cancer, and molecular genetic assessment with sequencing and digital PCR would be necessary in addition to immunostaining for accurate molecular diagnoses of the brain tumors.

A Case of Acute Reversible Encephalopathy with Neuronal Intranuclear Inclusion Disease Diagnosed by a Brain Biopsy: Inferring the Mechanism of Encephalopathy from Radiological and Histological Findings

A 75-year-old man presented with headache and disturbance of consciousness. Magnetic resonance imaging revealed edema localized mainly in the cortex and linear contrast enhancement. A brain biopsy revealed numerous astrocytes with inclusion, and genetic testing demonstrated prolonged GGC repeats in NOTCH2NLC. The present case provided two novel insights into the mechanism underlying encephalopathy associated with neuronal intranuclear inclusion disease. First, the histological findings at a site with contrast enhancement on magnetic resonance imaging did not demonstrate any organic association, such as the presence of inflammation or ischemic changes. Second, the imaging and cerebrospinal fluid findings demonstrated increased cerebral blood flow and opening of the blood-brain barrier, indicating the cause of the cerebral swelling.

Chronological Changes in the Expression Pattern of Hippocampal Prion Proteins During Disease Progression in Sporadic Creutzfeldt-Jakob Disease MM1 Subtype

The differential effects of sporadic Creutzfeldt-Jakob disease (sCJD) on the hippocampus and other neocortical areas are poorly understood. We aimed to reveal the histological patterns of cellular prion protein (PrPC) and abnormal prion protein (PrPSc) in hippocampi of sCJD patients and normal controls (NCs). Our study examined 18 postmortem sCJD patients (MM1, 14 cases; MM1 + 2c, 3 cases; MM1 + 2t, 1 case) and 12 NCs. Immunohistochemistry was conducted using 4 primary antibodies, of which 3 targeted the N-terminus of the prion protein (PrP), and 1 (EP1802Y) targeted the C-terminal domain. PrPC expression was abundant in the hippocampus of NCs, and the distribution of PrPC at CA3/4 was reminiscent of synaptic complexes. In sCJD cases with a disease history of <2 years, antibodies against the N-terminus could not detect synapse-like PrP expression at CA4; however, EP1802Y could characterize the synapse-like expression. PrPSc accumulation and spongiform changes became evident after 2 years of illness, when PrPSc deposits were more noticeably detected by N-terminal-specific antibodies. Our findings highlighted the chronology of histopathological alterations in the CA4 region in sCJD patients.

Immunohistochemical Phenotype of T Cells Invading Muscle in Inclusion Body Myositis

Inclusion body myositis (IBM) is an inflammatory myopathy of aged people with poor response to therapy. To characterize muscle-invading inflammatory cells, we performed immunohistochemical and ultrastructural studies on muscle biopsies from 10 patients with IBM with durations of illness from 3 to 84 months. At the surface of muscle fibers, 79% and 48% of CD8+ cells were positive for killer cell lectin-like receptor subfamily G, member 1 (KLRG1) and CD57, respectively. CD8+KLRG1+ cells are highly differentiated cytotoxic cells. On an average, 27% of CD8-CD57+KLRG1+ cells at the surface were CD4+. Proportions of CD28+ cells among KLRG1+ cells showed a negative correlation with duration of illness (r = -0.68). These changes indicated progressive differentiation of CD8+ T cells. Moreover, PD-1 expression on CD57+ and CD8+ cells increased early, then fluctuated, and reincreased in later stages. PD ligand-1 (PD-L1) and PD-L2 were expressed on adjacent cells including muscle fibers. T cell large granular lymphocytes (LGLs) are potent effector cells and cells with ultrastructure indistinguishable from LGLs were seen in the sarcoplasm along with lymphocytes undergoing degeneration. Together, along the course of IBM, some inflammatory cells retained the potential for cytotoxicity whereas others indicated suppression by exhaustion, senescence, or through the PD-1 pathway.

Case report: The origin of transmantle-like features

The transmantle sign is considered to be a magnetic resonance imaging feature specific to patients with type II focal cortical dysplasia; however, this sign can be difficult to distinguish from other pathologies, such as a radial-oriented white matter band in tuberous sclerosis. Here, we report a case showing a high-intensity area on T2-weighted and fluid-attenuated inversion recovery images extending from the ventricle to the cortex associated with atypical histopathological findings containing corpora amylacea. This case demonstrates that some instances of transmantle signs may be due to corpora amylacea accumulation.

Sacral myolipoma with involuntary contraction causing tethered cord syndrome: illustrative case

BACKGROUND

Spinal lipomas sometimes involve various ectopic tissues originating from the ectoderm, mesoderm, and endoderm in the process of morphological development.

OBSERVATIONS

A 29-year-old male patient with myolipoma of the conus medullaris at the S2 and S3 levels was described. The unusual finding, involuntary muscle contraction, was presented in an operative video and a literature review. In the present case, sacral myolipoma with involuntary contraction caused tethered cord syndrome in adulthood, and untethering surgery resolved continuous buttock and leg pain.

LESSONS

This rare finding is considered a surgical indication for adult patients with myolipoma.

EPEN-27. Epigenetic dissection of spinal ependymomas (SP-EPN) separates tumors with and withoutNF2 mutation

Ependymomas encompass multiple, clinically relevant tumor types based on localization, genetic alterations, and epigenetic and transcriptomic profiles. Tumors belonging to the methylation class of spinal ependymoma (SP-EPN) represent the most common intramedullary neoplasms in children and adults. However, molecular data of SP-EPN are scarce, and clear treatment recommendations are lacking. The only known recurrent genetic events in SP-EPN are loss of chromosome 22q and NF2 mutations. Yet, it remains unclear whether SP-EPN with germline or sporadic NF2 mutations or with NF2 wild type status differ clinically or molecularly. To provide a comprehensive molecular profile of SP-EPN, we integrated epigenetic, genomic, transcriptomic, and histological analyses of up to 237 cases. Clustering of methylation data revealed two distinct molecular SP-EPN subtypes. The distribution of NF2 mutated cases differed significantly across these subtypes (p <0.0001): The vast majority of tumors harboring either a previously known NF2 germline mutation or a sporadic mutation were assigned to subtypes A, whereas subtype B tumors mainly contained NF2 wild type sequences. In addition, subtype A tumors showed a lower frequency of MGMT promoter methylation (p= 0.018) and contained almost all pediatric patients of the cohort. Whole-exome sequencing (30 cases) identified numerous mutations in NF2 wild type and mutated tumors. Mutated genes in NF2 wild type tumors were enriched for genes associated with cell cycle and cytoskeleton. RNA sequencing revealed two distinct transcriptional groups with upregulation of proliferative genes in one group and upregulation of cilial genes in the other group. The molecular subtypes displayed subtle, but significant differences in the appearance of histopathological characteristics, such as surfaces, inflammation, and hyalinized vessels. Investigation of clinical parameters is ongoing and will complete the picture of SP-EPN heterogeneity as an important basis for future clinical decision-making.

[The 2021 WHO Classification of Tumors, 5th edition, Central Nervous System Tumors: A Short Review]

The 2021 WHO classification of tumors of the central nervous system, 5th edition (WHO CNS 5) is built on the previous, revised 4th edition, published in 2016, which incorporated molecular information into the diagnosis of brain tumors for the first time, breaking with the century-old histogenetic classification. WHO CNS 5 also adopted a series of recommendations of "the Consortium to Inform Molecular and Practical Approaches to CNS Tumor Taxonomy (cIMPACT)" that facilitates a consensus review of novel diagnostically relevant data and determines how such information can be fit into future CNS tumor classifications. In WHO CNS 5, the grading system was reformed to "grading within tumor types," and the tumor groups, especially diffuse gliomas, have been significantly restructured; the diffuse gliomas have been divided into the adult type and the pediatric type, the latter being subdivided into low-grade and high-grade gliomas. Based on molecular alterations, 22 novel tumor types are recognized, and some nomenclature has also been revised. The integrated, layered diagnosis of combining histology, grading, and molecular information was recommended to provide clinically relevant information.

Distribution of amyloid-β precursor protein-immunoreactive axons differs according to the severity of cerebral ischemia in autopsy brains

Amyloid-β precursor protein (APP) immunohistochemistry has been used to detect axonal injury in forensic neuropathology. However, axonal injury caused by cerebral ischemia has not been investigated by APP immunohistochemistry in detail. In particular, it is unknown if there is a correlation between the prognosis of cerebral ischemia and the distribution of axonal injury detected by APP immunohistochemistry. To address this issue, we compared the distribution of APP-immunoreactive axons in autopsy brains including lesions of acute phase of cerebral infarction in the territory of the middle cerebral artery (MCA) or internal carotid artery (ICA) with the degree of severity. The presence or absence of a midline shift was used as an indicator of the severity of cerebral ischemia. We identified a difference in the distribution of APP-immunoreactive axons between cases with and without a midline shift. In both the groups, APP-immunoreactive axons were detected at the margin of the ischemic lesions; however, only in cases with a midline shift, intense APP-immunoreactive axons were also found in areas other than the MCA and ICA territories, including the white matter of the cerebral hemispheres ipsilateral and contralateral to the ischemic lesions. This distribution was different from that of acute global cerebral ischemia cases reported previously. Our results indicate that the distribution of APP-immunoreactive axons differs according to the severity and type of cerebral ischemia, suggesting that the distribution of APP-immunoreactive axons is associated with the prognosis of cerebral ischemia.

Glioneuronal and neuronal tumors: A review with special reference to the new types in the WHO CNS5 classification

Glioneuronal and neuronal tumors (GNTs) are slow-growing lower-grade neuroepithelial tumors with mature neuronal and, less consistently, glial differentiation. Their identification has relied solely on histological proof of neuronal differentiation, which was considered to represent the well-differentiated nature of GNTs. However, after discovering the genetic alterations in GNTs, particularly those in the MAP-kinase pathway, it became evident that histological diagnoses are not always concurrent with genetic alterations and vice versa. Furthermore, since several inhibitors mediating the MAP-kinase pathway are available, at least for clinical trials, molecular-based classification is now warranted. Thus, the upcoming WHO Classification of Central Nervous System Tumors, 5^th edition (WHO5CNS) applied DNA methylation profiling to segregate low-grade neuroepithelial tumors. This review gives an overview of the pathological features of GNTs with particular reference to the newly listed tumor types in WHO5CNS. The knowledge and awareness of each tumor type are essential to make a correct diagnosis and avoid unnecessary radical resection and chemoradiotherapy, as GNTs are relatively indolent and have a prolonged clinical course. In addition, being distinctive in location, age group, and histology, the integration of clinicopathological information will help identify relevant tumor types of GNTs without genetic testing, even in resource-limited settings.

Clinical features and difficulty in diagnosis of Langerhans cell histiocytosis in the hypothalamic-pituitary region

Langerhans cell histiocytosis (LCH) is a multi-organ disorder that rarely involves the hypothalamic-pituitary region (HPR). HPR-LCH presents with severe progressive pituitary dysfunction and its prognosis is poor. The definitive diagnosis of LCH is considerably difficult and complicated owing to the occurrence of several diseases with similar manifestations in the HPR and its location in the deepest portion of the anterior skull base, in close proximity to important normal structures, severely limiting the size of the biopsy specimen. Chemotherapy is the established treatment modality for LCH; hence, timely and accurate diagnosis of LCH is essential for early therapeutic intervention. We retrospectively reviewed clinical features and biopsy procedures in four patients with HPR-LCH (all female, 28-44 years old) from 2009 to 2020. Maximum diameter of supra-sellar lesions was 23-35 mm and 2 cases had skip lesions. All patients demonstrated central diabetes insipidus, hyper-prolactinemia, and severe anterior pituitary dysfunction. Two of the patients had progressive disease. Furthermore, four patients presented body weight gain, two visual disturbance, and two impaired consciousness. The duration from onset to diagnosis of LCH was 3 to 10 (average 7.25) years. In total, eight operations were performed until final diagnosis. The percentage of correct diagnosis by biopsy was 50% (4/8). Clinical features of HPR-LCH are very similar to those of other HPR diseases, and their symptoms are progressive and irreversible. Clinicians should consider repeated biopsy with a more aggressive approach if the lesion is refractory to steroid therapy, in order to ensure accurate diagnosis and appropriate treatment.

HSP90 inhibition overcomes resistance to molecular targeted therapy in BRAFV600E mutant high-grade glioma

PURPOSE

Molecular targeted therapy using BRAF and/or MEK inhibitors has been applied to BRAFV600E mutant high-grade gliomas (HGGs); however, the therapeutic effect is limited by the emergence of drug resistance.

EXPERIMENTAL DESIGN

We established multiple paired BRAFV600E mutant HGG patient-derived xenograft (PDX) models based on tissues collected prior to and at relapse after molecular targeted therapy. Using these models, we dissected treatment resistant mechanisms for molecular targeted therapy and explored therapeutic targets to overcome resistance in BRAFV600E HGG models in vitro and in vivo.

RESULTS

We found that, despite causing no major genetic and epigenetic changes, BRAF and/or MEK inhibitor treatment deregulated multiple negative feedback mechanisms, which led to the re-activation of the MAPK pathway through c-Raf and AKT signaling. This altered oncogenic signaling primarily mediated resistance to molecular targeted therapy in BRAFV600E mutant HGG. To overcome this resistance mechanism, we performed a high-throughput drug screening to identify therapeutic agents that potently induce additive cytotoxicity with BRAF and MEK inhibitors. We discovered that HSP90 inhibition combined with BRAF/MEK inhibition coordinately deactivated the MAPK and AKT/mTOR pathways, and subsequently induced apoptosis via dephosphorylation of GSK3β (Ser9) and inhibition of Bcl-2 family proteins. This mediated potent cytotoxicity in vitro and in vivo in refractory models with acquired resistance to molecular-targeted therapy.

CONCLUSIONS

The combination of an HSP90 inhibitor with BRAF or MEK inhibitors can overcome the limitations of the current therapeutic strategies for BRAFV600E mutant HGG.

Myoclonic Epilepsy with Ragged-red Fibers with Intranuclear Inclusions

We herein report a case of myoclonic epilepsy with ragged-red fibers (MERRF) harboring a novel variant in mitochondrial cysteine transfer RNA (MT-TC). A 68-year-old woman presented with progressive myoclonic epilepsy with optic atrophy and peripheral neuropathy. A skin biopsy revealed p62-positive intranuclear inclusions. No mutations were found in the causative genes for diseases known to be related to intranuclear inclusions; however, a novel variant in MT-TC was found. The association between intranuclear inclusions and this newly identified MERRF-associated variant is unclear; however, the rare complication of intranuclear inclusions in a patient with typical MERRF symptoms should be noted for future studies.

Therapeutic Options for Recurrent Glioblastoma—Efficacy of Talaporfin Sodium Mediated Photodynamic Therapy

Recurrent glioblastoma (GBM) remains one of the most challenging clinical issues, with no standard treatment and effective treatment options. To evaluate the efficacy of talaporfin sodium (TS) mediated photodynamic therapy (PDT) as a new treatment for this condition, we retrospectively analyzed 70 patients who underwent surgery with PDT (PDT group) for recurrent GBM and 38 patients who underwent surgery alone (control group). The median progression-free survival (PFS) in the PDT and control groups after second surgery was 5.7 and 2.2 months, respectively (p = 0.0043). The median overall survival (OS) after the second surgery was 16.0 and 12.8 months, respectively (p = 0.031). Both univariate and multivariate analyses indicated that surgery with PDT and a preoperative Karnofsky Performance Scale were significant independent prognostic factors for PFS and OS. In the PDT group, there was no significant difference regarding PFS and OS between patients whose previous pathology before recurrence was already GBM and those who had malignant transformation to GBM from lower grade glioma. There was also no significant difference in TS accumulation in the tumor between these two groups. According to these results, additional PDT treatment for recurrent GBM could have potential survival benefits and its efficacy is independent of the pre-recurrence pathology.

Soluble APP-α and APP-β in cerebrospinal fluid as potential biomarkers for differential diagnosis of mild cognitive impairment

OBJECTIVES

Concentrations of soluble amyloid precursor proteins-α (sAPPα) and -β (sAPPβ) in cerebrospinal fluid (CSF) may reflect the neuropathology of Alzheimer's disease (AD). We previously reported that the concentrations of both sAPPα and sAPPβ were significantly higher in patients with mild cognitive impairment (MCI) due to AD (MCI-AD) than in control subjects without cognitive impairment. The present study analyzed whether these sAPPs are useful in the differential diagnosis of MCI.

METHODS

A modified and sensitive method was used to analyze concentrations of sAPPα and sAPPβ in CSF of patients with MCI-AD (n = 30) and MCI due to other causes (MCI-others) (n = 24). Phosphorylated tau (p-tau) and amyloid β-protein 42 (Aβ42) were also analyzed using standard methods.

RESULTS

CSF concentrations of sAPPα and sAPPβ were significantly higher in the MCI-AD than in the MCI-others group (p < 0.001). Furthermore, concentrations of both sAPPα and sAPPβ were highly correlated with the concentration of p-tau, consistent with our previous report.

CONCLUSIONS

Measurement of both sAPPs in CSF using sensitive methods can be helpful in the precise differential diagnosis of patients with MCI.

Grading of adult diffuse gliomas according to the 2021 WHO Classification of Tumors of the Central Nervous System

The grading of gliomas based on histological features has been a subject of debate for several decades. A consensus has not yet been reached because of technical limitations and inter-observer variations. While the traditional grading system has failed to stratify the risk of IDH-mutant astrocytoma, canonical histological and proliferative markers may be applicable to the risk stratification of IDH-wild-type astrocytoma. Numerous studies have examined molecular markers in order to obtain more clinically relevant information that will improve the risk stratification of gliomas. The CDKN2A/B homozygous deletion for IDH-mutant astrocytoma and the following three criteria for IDH-wild-type astrocytoma: the concurrent gain of whole chromosome 7 and loss of whole chromosome 10, TERT promoter mutations, and EGFR amplification, were identified as independent molecular markers of the worst clinical outcomes. Therefore, the 2021 World Health Organization (WHO) Classification of Tumors of the Central Nervous System adopted these molecular markers into the revised grading criteria of IDH-mutant and -wild-type astrocytoma, respectively, as a grading system within tumor types. Of note, several recent studies have shown that some low-grade IDH-wild-type astrocytoma lacking both the molecular glioblastoma signature and genetic alterations typical of pediatric-type gliomas may demonstrate a relatively indolent clinical course, suggesting the existence of lower-grade adult IDH-wild-type astrocytoma. In terms of oligodendroglioma, IDH-mutant, and 1p/19q codeleted, consistent makers that predict poor outcomes have not yet been identified, and, thus, the current criteria have remained unchanged. Molecular testing to fulfill the revised WHO criteria is, however, not always available worldwide, and in that case, an integrated diagnosis combining all available complementary information is highly recommended. This review discusses controversial issues surrounding legacy grading systems and newly identified potential genetic markers of adult diffuse gliomas and provides perspectives on future grading systems.

Symptomatic Change of an Intracranial Neuroepithelial Cyst 7 Years After Its Incidental Finding

A natural course of asymptomatic neuroepithelial cysts (NECs) is poorly understood due to its rarity. Herein we report a 23-year-old female patient of an asymptomatic NEC which grew in size from 1 cm to 5 cm and caused progressive symptoms seven years after its incidental finding. Partial resection of the cyst was performed for decompression and pathological examination and effectively achieved symptoms alleviation and regression of the cyst. Our case showed the importance of regular follow-up because NECs may show symptomatic change even in the late phase.

MPC-1 DNA methylome analysis suggested the presence of “true” IDH-wildtype lower-grade gliomas

Background: There will be significant changes in the diagnosis of IDH-wildtype adult-type gliomas in the upcoming 5th edition of the WHO Classification of Central Nervous System Tumours. IDH-wildtype lower grade gliomas (IDHwt LGGs) that harbor molecular features of glioblastoma (EGFR amplification, the combination of whole chromosome 7 gain and whole chromosome 10 loss (7+/10-), or TERT promoter mutations) will be diagnosed as glioblastomas (GBMs), while IDH-wildtype astrocytomas will not be included as a separate tumor type. However, IDHwt LGGs are a very heterogeneous group of tumors, and further investigation is warranted particularly in those without molecular features of glioblastoma. To elucidate the biology of IDHwt LGGs, we analyzed DNA methylation profile and survival time. Materials and Methods: Of the 724 adult-type diffuse glioma samples from a multi-institutional study, 64 IDHwt LGG, including 54 without any of molecular features of GBM and 10 with PDGFRA amplification or TERT promoter mutation, were examined using Infinium MethylationEPIC BeadChip. The raw data files (IDAT files) were analyzed by the web-based DNA methylation classifier provided by DKFZ (MolecularNeuropathology.org) or by R (Version 4.0.4) using the minfi (1.34.0) and Rtsne (0.15) packages. [Result] Twenty-three out of 54 IDHwt LGGs matched known methylation classes using the DKFZ methylation classifier. In t-Distributed Stochastic Neighbor Embedding clustering analysis, 20 cases formed a cluster within the methylation class family glioblastoma, IDH-wildtype, mainly subclass RTK I (“GBM” cluster). Another 29 IDHwt LGGs formed an independent cluster (“LGG” cluster) separate from any of the existing reference groups near but not overlapping with several subtypes of pediatric-type lower grade gliomas. The “LGG” cluster cases had significantly longer overall survival than the “GBM” cluster cases. Discussion: Methylation profiling showed that IDHwt LGGs without molecular features of GBM were heterogeneous group of tumors. Our data suggested the presence of “true” IDHwt LGGs with intermediate prognosis.