Diffuse Leptomeningeal Glioneuronal Tumor Research Articles

PATH-57. CLINICAL AND MOLECULAR FEATURES OF METHYLATION CLASS DIFFUSE LEPTOMENINGEAL GLIONEURONAL TUMOR

Abstract Genome-wide DNA methylation profiling can help identify rare CNS tumors, including diffuse leptomeningeal glioneuronal tumor (DLGNT). Due to the infrequency of this entity, DLGNT remains poorly understood. To help resolve uncertainty regarding DLGNT, we examined epidemiologic, histologic, and molecular features of 32 (21 newly profiled, 11 publicly available) tumors matching to DLGNT by the DKFZ classifier (v12, score >=0.85). Of these tumors, 25 matched to DLGNT subtype 1 and seven to subtype 2. Subject median age was 12 years in subtype 1 and 22 years in subtype 2 (14.5 overall, range 2-44), with equal numbers of females and males (n=16 each). Spinal cord was the most frequently involved site (n=21), but intracranial lesions were observed (n=6). Leptomeningeal involvement was noted in only four of 11 tumors with available imaging descriptions. In the subset of cases available for histologic review (n=19), oligodendrocyte-like morphology was present in over half (n=11). Microvascular proliferation was uncommon (n=5). Chromosome 1p loss was observed in 29 (91%), and 1p/19q co-deletion was observed in 18 tumors (56%). Gains of 1q and 7q were each observed in 12 (38%), and whole chromosome 7 gain was observed in eight (25%). Loss of 22q was seen in 12 (38%). In the subset of tumors with fusion testing (n=15), KIAA1549::BRAF fusion was present in 12 (80%), and one showed a QKI::RAF1 fusion. Five tumors harbored BRAF mutations, and one harbored a break-point in BRAF without a known fusion partner. In nine subjects with clinical follow-up, there was one death after 3.1 years, and the remaining subjects were alive with a median follow-up of 6.4 years (maximum 19 years). Progression-free survival (PFS) was available for six subjects with a median PFS of 6 years. Presentation of DLGNT without noted leptomeningeal involvement appears common. Further characterization of subject outcomes will help clarify the clinical behavior of DLGNT.

PATH-17. MOLECULAR CLASSIFICATION OF H3K27-WILDTYPE SPINAL CORD GLIOMAS: IMPLICATIONS FOR PROGNOSIS AND THERAPEUTICS

Abstract BACKGROUND H3K27-wildtype spinal cord gliomas (H3WT-SCGs) are rare and heterogeneous tumors that present significant challenges in pathological classification. Traditional histologic diagnoses often do not align well with the underlying molecular characteristics of these tumors. METHODS We characterized 55 cases of H3WT-SCGs using a comprehensive approach that included DNA methylation array, whole-exome sequencing, transcriptome sequencing, proteomics, and single-cell RNA sequencing. Unsupervised clustering analysis was performed to identify distinct molecular subtypes. RESULTS The analysis identified seven distinct spinal cord methylation (SCM) clusters: pilocytic astrocytomas (PA-SPINE), PA-immune enriched (PA-IME), diffuse leptomeningeal glioneuronal tumor (DLGNT), subependymoma (SUBEPN-SPINE), glioblastoma-like (GBM-like), and pleomorphic xanthoastrocytoma-like (PXA-like). There was a 61.8% discordance between SCM classes and traditional histologic diagnoses. The new molecular classification provided a better correlation with molecular features and patient prognosis. BRAF fusions were enriched in PA-SPINE and DLGNT (p = 0.04), and DLGNT showed significant chromosomal alterations, including 1p loss (p = 6.5e-08) and 1q gain (p = 3.6e-05). Notably, we identified two distinct classes of PA-SPINE: adult (older than 18 years) and pediatric. Adult PAs exhibited lower frequencies of BRAF fusions (p = 1.4e-03), shorter tumor lengths (p = 3.7e-04), and longer progression-free survival (p = 0.062). Adult PA neoplastic cells were less differentiated, with higher expression of EGFR and neuronal markers, and lower cytokine and chemokine expression compared to pediatric cases. Single-cell analysis revealed reduced infiltration of monocyte-derived macrophages and proliferative myeloid cells in adult cases. Both PA-IME and PA-pediatric clusters were characterized as immune-hot tumors with high immune cell enrichment. CONCLUSION This study defined clinically relevant molecular classes of H3WT-SCGs that better reflect patient prognosis and molecular characteristics compared to traditional histologic diagnoses. The findings suggest potential therapeutic implications, especially in immune-hot tumors like IME and PA-pediatric, which could benefit from targeted immunotherapies.

Spontaneous Pneumocephalus associated with leptomeningeal glioneuronal tumor in an adult; A rare case report

ObjectiveTo report a rare case of otogenic tension pneumocephalus as a complication of a diffuse leptomeningeal glioneuronal tumor in a patient with a ventriculoperitoneal (V. P.) shunt. PatientsTwenty-three- year-old man with a confirmed diffuse leptomeningeal glioneuronal tumor diagnosis was treated for temporal bone defect and considerable pneumocephalus one year after V. P. shunt. Intervention(s)The patient underwent a Transmastoid, retrolabyrinthine approach. The defect was closed with temporalis facia graft and conchal cartilage as a double-layer closure, and then DuraSeal® was placed over the repaired area. Main outcome measure(s)Resolution of the pneumocephalus. ResultsThere was a significant reduction in the pneumocephalus on the first day post-operatively. ConclusionsSpontaneous or secondary pneumocephalus development should be considered in patients with brain tumors, hydrocephalus, and patients who undergo V.P. shunt insertion.

The Role of Radiotherapy, Chemotherapy, and Targeted Therapies in Adult Intramedullary Spinal Cord Tumors.

Intramedullary primary spinal cord tumors are rare in adults and their classification has recently evolved. Their treatment most frequently relies on maximal safe surgical resection. Herein, we review, in light of the WHO 2021 classification of central nervous system tumors, the knowledge regarding the role of radiotherapy and systemic treatments in spinal ependymomas, spinal astrocytomas (pilocytic astrocytoma, diffuse astrocytoma, spinal glioblastoma IDH wildtype, diffuse midline glioma H3-K27M altered, and high-grade astrocytoma with piloid features), neuro-glial tumors (ganglioglioma and diffuse leptomeningeal glioneuronal tumor), and hemangioblastomas. In spinal ependymomas, radiotherapy is recommended for incompletely resected grade 2 tumors, grade 3 tumors, and recurrent tumors not amenable to re-surgery. Chemotherapy is used in recurrent cases. In spinal astrocytomas, radiotherapy is recommended for incompletely resected grade 2 astrocytomas and grade 3 or 4 tumors as well as recurrent tumors. Chemotherapy is indicated for newly diagnosed high-grade astrocytomas and recurrent cases. In hemangioblastomas not amenable to surgery, radiotherapy is an effective alternative option. Targeted therapies are playing an increasingly important role in the management of some intramedullary primary spinal cord tumor subtypes. BRAF and/or MEK inhibitors have demonstrated efficacy in pilocytic astrocytomas and glioneuronal tumors, belzutifan in von Hippel-Lindau-related hemangioblastomas, and promising results have been reported with ONC201 in diffuse midline glioma H3-K27M altered.

A case of a (not so) diffuse leptomeningeal glioneuronal tumor with an unusual clinical history.

A case of a (not so) diffuse leptomeningeal glioneuronal tumor with an unusual clinical history.

Local intracerebral form of diffuse leptomeningeal glioneuronal tumor – a new entity of the group of epileptogenic neoplasms?

Local intracerebral form of diffuse leptomeningeal glioneuronal tumor – a new entity of the group of epileptogenic neoplasms?

Unraveling morphology, methylation profiling, and diagnostic challenges in BRAF-Mutant pediatric glial and glioneuronal tumors.

To elucidate the relationship between DNA methylation profiling (DMP) and pathological diagnosis (PD) in pediatric glial and glioneuronal tumors with B-Raf proto-oncogene, serine/threonine kinase (BRAF) mutations, addressing their diagnostic challenges. This retrospective study, conducted in Saudi Arabia, analyzed 47 cases from the Children's Brain Tumor Network online database using scanned images, next-generation sequencing data, and methylation profiles processed using the Heidelberg methylation brain tumor classifiers v12.5 and v12.8. The data was last access on 10 November 2023. The highest prevalence of BRAF mutations was observed in pilocytic astrocytoma and ganglioglioma. The DMP was consistent with PD in 23 cases, but discrepancies emerged in others, including diagnostic changes in diffuse leptomeningeal glioneuronal tumor and polymorphous low-grade neuroepithelial tumor of the young. A key inconsistency appeared between a pilocytic astrocytoma MC and a glioneuronal tumor PD. Two high-grade astrocytomas were misclassified as pleomorphic xanthoastrocytomas. Additionally, low variant allelic frequency in gangliogliomas likely contributed to misclassifications as control in 5 cases. This study emphasized the importance of integrating DMP with PD in diagnosing pediatric glial and glioneuronal tumors with BRAF mutations. Although DMP offers significant diagnostic insights, its limitations, particularly in cases with low tumor content, necessitate cautious interpretation, as well as its use as a complementary diagnostic tool, rather than a definitive method.

LGG-12. INTEGRATED CLINICAL AND MOLECULAR CHARACTERIZATION OF 200 DISSEMINATED PEDIATRIC LOW-GRADE GLIOMAS

Abstract Pediatric low-grade gliomas (PLGG) have excellent outcomes overall but are a major clinical challenge when disseminated. Diffuse leptomeningeal glioneuronal tumor (DLGNT) is a recognised entity both clinically and pathologically, however many disseminated LGG (DLGG) fall outside this diagnosis. To better understand the clinical and molecular features of DLGG as well as risk factors for dissemination, we assembled an international consortium of 30 sites, contributing over 200 patients with clinical annotation, along with genomic and methylation profiling. DLGG have worse progression-free (PFS) and overall survival (OS) than PLGG overall (p<0.0001). Seventy (35%) presented with a localized mass and secondary dissemination, including some with initial gross-total resection. The most common growth pattern observed (n=77, 40%) is a dominant suprasellar/optic pathway tumor with leptomeningeal drop-metastases involving the brainstem and spinal cord. Only 27 (14%) patients had diffuse tumors (without an identifiable dominant mass), and these had significantly worse OS (p=0.03). The most common pathologic diagnosis was pilocytic/pilomyxoid astrocytoma (n=92; 53%). DLGNT comprised a minority of cases (n=23, 14%), with a trend (p=0.056) towards worse survival compared to other diagnoses. The most frequent molecular alteration was BRAF fusion (78/151 with molecular testing; 52%), followed by FGFR mutations or fusions (18/151; 12%). BRAF V600E was underrepresented (14/151; 9%). 1p deletion was rare (17 patients) but highly associated with DLGNT. Methylation classification (n=70) was highly concordant with histologic diagnoses rather than clinical behavior. Importantly, patients who received upfront targeted therapies (TT; BRAF and/or MEK inhibition, n=9) had better PFS compared to those receiving chemotherapy (n=146, p=0.05). Furthermore, patients who were treated sequentially with chemo then TT had longer PFS on TT (p=0.011). This study presents the largest cohort of DLGG to date, expanding our understanding of the clinical, pathologic, and molecular features of this disease and supports the use of upfront targeted therapy.

OTHR-26. MINIMALLY-INVASIVE MOLECULAR DIAGNOSIS OF DIFFUSE LEPTOMENINGEAL GLIONEURONAL TUMOR (DLGNT) USING CEREBROSPINAL FLUID CELL-FREE DNA SEQUENCING IN PEDIATRIC AND YOUNG ADULT PATIENTS

Abstract BACKGROUND Diffuse leptomeningeal glioneuronal tumor (DLGNT) presents with nodular leptomeningeal disease throughout the neuroaxis and is characterized by the presence of KIAA1549::BRAF fusion and chromosome arm 1p deletion. Concomitant gain of chromosome arm 1q is associated with poor prognosis. Diagnosis by meningeal biopsy is often non-diagnostic due to sampling error or yields insufficient material for molecular testing. We hypothesized that analysis of cell free DNA (cfDNA) from cerebrospinal fluid (CSF) could represent a superior diagnostic modality. METHODS We analyzed CSF samples from 9 suspected DLGNT patients, median age of 19.5 years with a 5:4 male:female ratio using MSK-IMPACT, a hybridization capture-based next-generation DNA sequencing panel, including matched germline. RESULTS Prior tissue biopsy was done in 7 patients; 6 were negative for the KIAA1549:BRAF fusion and 1 was positive. Of the 6 biopsies negative for the fusion, analysis of CSF cfDNA detected KIAA1549::BRAF fusion in 3/6 (50%) of patients, who were all subsequently started on MEK inhibitor therapy. The other 3 patients were negative for KIAA1549:BRAF fusion on both biopsy and CSF cfDNA. One patient received biopsy confirmation of KIAA1549::BRAF fusion after CSF cfDNA analysis detected the mutation. In addition, in one patient with prior tissue-confirmed KIAA1549::BRAF fusion, the fusion was not detected in CSF cfDNA during/after treatment with a MEK inhibitor, but additional somatic alterations and DNA copy number profiles were similar to those found in prior biopsies. Additional somatic alterations were identified in ATRX, BCOR, RARA, STAT5A, SPOP, PPM1D, MED12, KMT2C, RECQL andSETD2, including likely oncogenic secondary driver alterations that have not been previously reported in DLGNT. CONCLUSIONS Given the high molecular diagnostic yield and concordance with open biopsy, cfDNA CSF sequencing should be considered as a first line diagnostic maneuver for patients with suspected DLGNT, followed by surgical biopsy only if CSF testing is non-diagnostic.

DIPG-57. INITIAL AND EARLY METASTATIC SPREAD IN DIPG AND DIFFUSE MIDLINE GLIOMA, H3 K27-ALTERED - REPORT FROM THE EUROPEAN SOCIETY FOR PEDIATRIC ONCOLOGY (SIOPE) AND INTERNATIONAL DIPG/DMG REGISTRIES

Abstract BACKGROUND We aimed to assess frequency, patterns and potential prognostic impact of initial and early dissemination in pediatric patients with diffuse intrinsic pontine glioma (DIPG) and diffuse midline glioma, H3K27-altered (DMG). METHODS 199 patients (age, 0-18 years) with DIPG/DMG and positive CSF cytology and/or metastases on MRI at diagnosis (Types 1-3) were identified within the SIOPE and International DIPG/DMG Registries. Data on metastatic first progression (PD) in DIPG/DMG (Type 4) were analyzed from the HIT-HGG-2007/2013 trials. RESULTS Dissemination at diagnosis was present in 5% of patients with DIPG/DMG (16.9% in non-pontine DMG). For all 199 patients with initially disseminated pontine (n=166) and non-pontine DMG (n=33), median overall survival (OS) was 10±0.5 months and progression-free survival (PFS) was 6.6±0.2 months. Tumor cells in the CSF without metastases on initial MRI (Type 1) were detected in 12 patients. Four patients had no primary tumor but primary extensive leptomeningeal dissemination resembling diffuse leptomeningeal glioneuronal tumor, molecularly confirmed as DMG, with aggressive course (Type 2). 183 DIPG/DMG patients were identified with primary tumor and metastases on MRI at diagnosis (Type 3). OS and PFS was superior in patients receiving additional treatment to radiotherapy (n=124), without significant differences between focal and craniospinal irradiation. Metastatic spread at first progression (Type 4) occurred in 32.1% (65.3% in non-pontine DMG) of 224 HIT-HGG patients with DMG and recorded PD. OS of patients with metastatic PD was inferior to local PD (median, 10.8±0.9 vs. 13.3±0.9 months, p=0.005), as was post-progression survival (median, 3.1±0.4 vs. 5.2±0.5 months, p=0.003). CONCLUSIONS We observed a propensity for early dissemination in (especially non-pontine) DMG. While additional treatment beyond radiotherapy seems beneficial, preventing dissemination at progression (e.g., by upfront CSI) may help to prolong survival of patients with DMG and possibly provide options for further therapy.

Pediatric Diffuse Leptomeningeal Glioneuronal Tumors: Diagnosis, Follow-up, and Treatment Options.

To highlight the diagnosis, follow-up, and treatment options for diffuse leptomeningeal glioneuronal tumor (DLGNT) by examining pediatric patients diagnosed with DLGNT by molecular pathological evaluation and next generation sequencing at our center. In this retrospective analysis, patients diagnosed with DLGNT between January 2017 and December 2022 are outlined according to their demographic data, radiological data, pathology results, treatments, and follow-up data. Four patients were diagnosed with DLGNT. All the patients were male. The mean age was 6.5 years. All but one patient had symptoms of increased intracranial pressure. An open biopsy was obtained from all patients for diagnosis. Three patients received radiotherapy and chemotherapy after the diagnosis. Two patients died during their follow-up, one of them in the early postoperative period. Two patients were clinically and radiologically stable in their follow-up after treatment. Further work with larger cohorts is required to determine a common algorithm for DLGNT treatment and follow-up. This analysis may keep this entity in mind in patients with pediatric communicating hydrocephalus and may present insight into diagnosis, follow-up, and treatment options.

Dural and Leptomeningeal Diseases: Anatomy, Causes, and Neuroimaging Findings.

Meningeal lesions can be caused by various conditions and pose diagnostic challenges. The authors review the anatomy of the meninges in the brain and spinal cord to provide a better understanding of the localization and extension of these diseases and summarize the clinical and imaging features of various conditions that cause dural and/or leptomeningeal enhancing lesions. These conditions include infectious meningitis (bacterial, tuberculous, viral, and fungal), autoimmune diseases (vasculitis, connective tissue diseases, autoimmune meningoencephalitis, Vogt-Koyanagi-Harada disease, neuro-Behçet syndrome, Susac syndrome, and sarcoidosis), primary and secondary tumors (meningioma, diffuse leptomeningeal glioneuronal tumor, melanocytic tumors, and lymphoma), tumorlike diseases (histiocytosis and immunoglobulin G4-related diseases), medication-induced diseases (immune-related adverse effects and posterior reversible encephalopathy syndrome), and other conditions (spontaneous intracranial hypotension, amyloidosis, and moyamoya disease). Although meningeal lesions may manifest with nonspecific imaging findings, correct diagnosis is important because the treatment strategy varies among these diseases. ©RSNA, 2023 Online supplemental material and the slide presentation from the RSNA Annual Meeting are available for this article. Quiz questions for this article are available through the Online Learning Center.

LGG-12. CLINICAL AND MOLECULAR FEATURES OF DISSEMINATED PEDIATRIC LOW-GRADE GLIOMA

Abstract Although most pediatric LGG (PLGG) have excellent long-term survival, there is a subset of cases that disseminate throughout the neuraxis (DLGG) that have very poor outcomes. The reason for this aggressive behavior is unknown but we hypothesize that distinct and specific biological mechanisms underlie the metastatic ability. The methylation-based class of diffuse leptomeningeal glioneuronal tumor (DLGNT) is characterized by MAPK pathway activating fusions with chromosome 1p loss, 19q loss, and/or 1q gain. However, it is unknown what proportion of DLGG match the DLGNT group, and which other methylations classes are at risk of metastasis. To improve our understanding of this rare patient population, we created an international DLGG consortium. Data from the first 68 cases shows a broad age distribution and no sex predilection. As expected, DLGG has much worse prognosis than the overall PLGG population. Virtually all DLGG progress at 5 years, compared to a quarter of other PLGG, and DLGG are 5-times more likely to die at 10 years. We observe three patterns of dissemination – 35% present with a localized mass and have secondary dissemination, 50% with disseminated tumor and a clear dominant mass, and 15% with disseminated disease without a dominant mass. In 47 patients with molecular testing, BRAF fusions accounted for 64% of driver alterations. Additional alterations were identified less frequently, including BRAF V600E (9%), FGFR1 alterations (9%), and KRAS mutations (4%). In 25 patients with methylation profiling, 10 (40%) successfully classified with a calibrated score above 0.8, illustrating that many cases do not fit a defined methylation group. The most common methylation classification was pilocytic astrocytoma (5 patients), and surprisingly only two patients classified as DLGNT. In sum this study illustrates the variable clinical behaviour associated with metastasis in PLGG and expands the range of molecular driver alterations, including ones previously unreported in DLGNT.

Diffuse Leptomeningeal Glioneuronal Tumor (DLGNT) with Direct Cystic Infiltration of the Optic Chiasm and Tracts (P1-9.003)

<h3>Objective:</h3> N/A <h3>Background:</h3> Diffuse leptomeningeal glioneuronal tumor (DLGNT) is a rare pediatric neoplasm categorized by the WHO in 2016. It is characterized by communicating hydrocephalus, slow tumor growth, CSF with absence of tumor cells, and MRI showing diffuse leptomeningeal enhancement and cystic changes. Here we present, to our knowledge, the first case in which direct cystic tumor infiltration of the optic apparatus was the initial manifestation. <h3>Design/Methods:</h3> N/A <h3>Results:</h3> A 3-year-old boy developed emesis, altered mental status, bilateral leg weakness, and decreased visual acuity to 20/125 OD and 20/160 OS. MRI showed hydrocephalus and diffuse leptomeningeal enhancement of the brain and spine. Lumbar puncture showed pleocytosis, elevated protein, positive enterovirus PCR, and opening pressure of 55 cm H2O. VP shunt was placed for presumed enterovirus meningitis. Symptoms of hydrocephalus resolved but vision did not improve. Exam showed optic disc pallor bilaterally and no papilledema. OCT demonstrated retinal nerve fiber layer thinning bilaterally. Visual decline progressed despite normalization of ICP. Repeat MRI brain/orbits showed multiple new subpial cysts along the optic tracts and optic chiasm. Filum biopsy showed rare inflammatory cell. Review of the pathology and radiological findings led to a consensus of DLGNT with cysts compressing and infiltrating optic chiasm and nerves. The patient was started on the MEK inhibitor trametinib, with stabilization of MRI findings and vision, but unfortunately without visual improvement. <h3>Conclusions:</h3> Pathologic confirmation of DLGNT can be difficult as safely obtained biopsy samples are typically small. In this case, bilateral optic neuropathy developed due to infiltration of the optic nerves, chiasm and tracts, while papilledema was never seen. MEK inhibitor therapy was initiated with Trametinib leading to stabilization in disease burden. This diagnosis should be considered in pediatric patients with communicating hydrocephalus, diffuse leptomeningeal enhancement, and elevated CSF protein with otherwise normal profile including absence of tumor cells. <b>Disclosure:</b> Dr. Paddock has nothing to disclose. Dr. Dinkin has received personal compensation in the range of $10,000-$49,999 for serving as an Expert Witness for WILSON ELSER MOSKOWITZ EDELMAN &amp; DICKER LLP. Dr. Dinkin has received personal compensation in the range of $5,000-$9,999 for serving as an Expert Witness for Rehabilitation Alternative Services, Inc.. Dr. Dinkin has received personal compensation in the range of $500-$4,999 for serving as an Expert Witness for AMFS / Medical Experts Nationwide. Dr. Dinkin has received personal compensation in the range of $500-$4,999 for serving as an Expert Witness for Bekman, Marder, Hopper, Malarkey &amp; Perlin, L.L.C.. Dr. Dinkin has received personal compensation in the range of $500-$4,999 for serving as an Expert Witness for Northwestern Mutual. Dr. Dinkin has received personal compensation in the range of $5,000-$9,999 for serving as an Expert Witness for Young Conaway Stargatt &amp; Taylor.

Integrated genetic profiling of archival pediatric high-grade glial tumors and reassessment with 2021 WHO classification of paediatric CNS tumours

Though rare, pediatric high-grade gliomas (pHGG) are a leading cause of cancer-related mortality in children. We wanted to determine whether our currently available clinical laboratory methods could better define diagnosis for pHGG that had been archived at our institution for the past 20 years (1998 to 2017). We investigated 33 formalin-fixed paraffin-embedded pHGG using ThermoFisher Oncoscan SNP microarray with somatic mutation analysis, Sanger sequencing, and whole genome sequencing. These data were correlated with historical histopathological, chromosomal, clinical, and radiological data. Tumors were subsequently classified according to the 2021 WHO Classification of Paediatric CNS Tumours. All 33 tumors were found to have genetic aberrations that placed them within a 2021 WHO subtype and/or provided prognostic information; 6 tumors were upgraded from WHO CNS grade 3 to grade 4. New pHGG genetic features were found including two small cell glioblastomas with H3 G34 mutations not previously described; one tumor with STRN-NTRK2 fusion; and a congenital diffuse leptomeningeal glioneuronal tumor without a chromosomal 1p deletion but with KIAA1549-BRAF fusion. Overall, the combination of laboratory methods yielded key information for tumor classification. Thus, even small studies of these uncommon tumor types may yield new genetic features and possible new subtypes that warrant future investigations.

Rapidly progressive diffuse leptomeningeal glioneuronal tumor in an adult female: illustrative case.

Diffuse leptomeningeal glioneuronal tumor (DLGNT) is a rare brain tumor only recently classified by the World Health Organization in 2016 and has few reports on its incidence in adults. The authors describe a case of DLGNT presenting in a 47-year-old female with seizures, cranial neuropathies, and communicating hydrocephalus with rapid clinical progression. Workup demonstrated progressive leptomeningeal enhancement of the skull base, cranial nerves, and spine, and communicating hydrocephalus. Elevated serum rheumatological markers and early response to systemic corticosteroids and immunosuppressant therapy complicated the diagnosis. Multiple biopsy attempts were required to obtain diagnostic tissue. Pathology demonstrated hypercellularity surrounding leptomeningeal vessels with nuclear atypia, staining positive for GFAP, Olig2, S100, and synaptophysin. Molecular pathology demonstrated loss of chromosome 1p, BRAF overexpression but no rearrangement, and H3K27 mutation. Repeat cerebrospinal fluid (CSF) diversion procedures were required for hydrocephalus management due to high CSF protein content. This report describes a rare, aggressive, adult presentation of DLGNT. Leptomeningeal enhancement and communicating hydrocephalus should raise suspicion for this disease process. Biopsy at early stages of disease progression is essential for early diagnosis and prompt treatment. Further study into the variable clinical presentation, histological and molecular pathology, and optimal means of diagnosis and management is needed.

Diffuse Leptomeningeal Glioneuronal Tumor Involving Circle of Willis and Spinal Nerve Roots.

Diffuse Leptomeningeal Glioneuronal Tumor Involving Circle of Willis and Spinal Nerve Roots.

DIFFUSE LEPTOMENINGEAL GLIONEURONAL TUMOR: A RARE CAUSE OF MALIGNANT PLEURAL EFFUSION

DIFFUSE LEPTOMENINGEAL GLIONEURONAL TUMOR: A RARE CAUSE OF MALIGNANT PLEURAL EFFUSION

Diffuse leptomeningeal glioneuronal tumor (DLGNT) with hydrocephalus as an initial symptom mimicking tuberculous meningitis: A case report.

The Article Abstract is not available.

Prognostic factors in diffuse leptomeningeal glioneuronal tumor (DLGNT): a systematic review

Diffuse leptomeningeal glioneuronal tumor (DLGNT) is a rare tumor, first described by the WHO Classification of Central Nervous System Tumors in 2016. The clinical course is variable. Most tumors have low-grade histological findings although some may have more aggressive features. The goal of this systematic review was to identify prognostic factors for poor overall survival (OS). We performed a systematic review using three databases (PubMed, Google Scholar, and Embase) and the following search terms: diffuse leptomeningeal glioneuronal tumor, DLGNT, DLMGNT. Statistical analysis was performed using Statistica 13.3. We included 34 reports in our review comprising 63 patients, published from 2016 to 2022. The median OS was 19months (range: 12-51months). Using multivariable Cox survival analysis, we showed that Ki-67 ≥ 7%, age > 9years, symptoms of elevated intracranial pressure (ICP) at admission, and the presence of contrast-enhancing intraparenchymal tumor are associated with poor OS. Receiver operating characteristic (ROC) analysis identified Ki-67 ≥ 7% as a significant predictor of poor OS. Signs or symptoms of increased ICP with imaging findings of diffuse leptomeningeal enhancement should raise suspicion for DLGNT. In our systematic review, Ki-67 ≥ 7% was the most important prognostic factor for OS in DLGNT. The presence of intraparenchymal tumor with contrast enhancement was thought to represent disease progression and, together with patient age, was associated with poor OS.