Diffuse Leptomeningeal Glioneuronal Tumor of Childhood

Diffuse Leptomeningeal Glioneuronal Tumor in Adults: Case Report and Literature Review

Introduction

Diffuse leptomeningeal glioneuronal tumor (DLGNT), a new addition to the 2016 World Health Organization (WHO) classification, is a rare childhood neoplasm presenting with disseminated leptomeningeal enhancement and an occasional intraparenchymal mass. Diagnosis is often impeded by infectious/immunological differentials, necessitating a biopsy to confirm the diagnosis. We report an adult male with DLGNT without hydrocephalus, which is rare in patients with cerebellar masses.

Case Presentation

A 56-year-old man presented with headaches, vertigo, diplopia, impaired hearing, and gait imbalance over 6 months. Magnetic resonance imaging showed a cystic right cerebellar mass with its leptomeningeal dissemination but without hydrocephalus. Cerebrospinal fluid analysis revealed elevated proteins with CD56-positive tumor cells. Cerebellar lesion biopsy verified the diagnosis of DLGNT (WHO Grade 3) with KIAA1549::BRAF fusion and 1p deletion. Radiotherapy was prematurely aborted due to clinical deterioration. The patient was subsequently discharged to palliative home care and lost to follow-up.

Conclusion

We conducted the first review of all 34 adult DLGNT cases, including ours (one of the oldest), hitherto published in the literature. The majority presented with signs and symptoms of increased intracranial pressure. 52.0% of adult DLGNT patients were alive at follow-up. DLGNT should be considered in the differential diagnoses of diffuse leptomeningeal enhancement in imaging. Further studies comparing pediatric and adult subgroups of DLGNT are needed to evaluate histopathological prognosticators and standardize therapy for both subpopulations.

Diffuse Leptomeningeal Glioneuronal Tumor: First Description of Metastasis to the Lung and Bone Marrow

Diffuse leptomeningeal glioneuronal tumor (DLGNT) is a rare neoplasm of the central nervous system (CNS) that primarily affects the leptomeninges. However, it can also involve the brain parenchyma and spinal cord. We report the first case of metastasis of this primary CNS tumor to the lung and bone marrow. An 18-year-old male was diagnosed with DLGNT through meningeal biopsy after multiple events of transient neurologic signs and symptoms that included recurrent episodes of encephalopathy, seizures, cerebral vasospasms, cranial nerve palsy, and urinary dysfunction. Five months after diagnosis, the patient presented with pancytopenia and pulmonary effusion. At that time, he was being treated with temozolomide, after radiation treatment to the brain and spinal cord. Bone marrow biopsy and pleural cytology revealed systemic metastases from the primary CNS tumor. He was then treated with chemotherapy with carboplatin and vincristine which improved his condition for two and a half months. Unfortunately, the patient died of a high systemic metastatic burden. Primary CNS tumors rarely produce systemic metastases, and this is the first report of DLGNT with bone marrow and pulmonary metastases. Chemotherapy with carboplatin and vincristine should be considered as a treatment for patients with DLGNT, as the patient presented a systemic response with clinical and radiological improvement.

Diffuse Leptomeningeal Glioneuronal Tumor with FGFR1 Mutation in a 29-Year-Old Male

This study reports on diffuse leptomeningeal glioneuronal tumor (DL-GNT) in a 29-year-old male. DL-GNT is a rare central nervous system (CNS) tumor mostly seen in children and only few cases have been reported in adult patients. Our patient presented with a chronic headache that lasted for five months. MR imaging showed mild hydrocephalus, multiple rim-enhancing nodular lesions in the suprasellar cistern, diffuse leptomeningeal enhancement in the lumbosacral area, and multiple small non-enhancing cyst-appearing lesions not suppressed on fluid attenuated inversion recovery (FLAIR) images in the bilateral basal ganglia, thalami, and cerebral hemispheres. Under the impression of germ cell tumor with leptomeningeal seeding, the patient underwent trans-sphenoidal tumor removal. DL-GNT was pathologically confirmed and FGFR1 mutation was detected through a next-generation sequencing test. In conclusion, a combination of leptomeningeal enhancement and multiple parenchymal non-enhancing cyst-appearing lesions not suppressed on FLAIR images may be helpful for differential diagnosis despite overlapping imaging features with many other CNS diseases that have leptomeningeal enhancement.

Diffuse Leptomeningeal Glioneuronal Tumour

Diffuse leptomeningeal glioneuronal tumours (DL-GNT) are rare, with an unknown incidence but fewer than 100 cases reported since 2012. The clinical presentation is non-specific, ranging from abdominal to neurological symptoms. Presently, definitive radiological criteria aren't established, but some features, such as nodules, characteristic extension patterns and post-contrast leptomeningeal enhancement, are found to be prominent. We present the case of a 14-year-old male with an advanced case of DL-GNT, with MRI showing all the features of what is currently thought to be the typical radiological presentation. The patient is currently undergoing treatment but remains severely handicapped by the disease.

Leptomeningeal dissemination in pediatric brain tumors

Leptomeningeal disease (LMD) in pediatric brain tumors (PBTs) is a poorly understood and categorized phenomenon. LMD incidence rates, as well as diagnosis, treatment, and screening practices, vary greatly depending on the primary tumor pathology. While LMD is encountered most frequently in medulloblastoma, reports of LMD have been described across a wide variety of PBT pathologies. LMD may be diagnosed simultaneously with the primary tumor, at time of recurrence, or as primary LMD without a primary intraparenchymal lesion. Dissemination and seeding of the cerebrospinal fluid (CSF) involves a modified invasion-metastasis cascade and is often the result of direct deposition of tumor cells into the CSF. Cells develop select environmental advantages to survive the harsh, nutrient poor and turbulent environment of the CSF and leptomeninges. Improved understanding of the molecular mechanisms that underlie LMD, along with improved diagnostic and treatment approaches, will help the prognosis of children affected by primary brain tumors.

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

BACKGROUND

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.

OBSERVATIONS

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.

LESSONS

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 in an 8-year-old girl: case report and review of the literature

Diffuse leptomeningeal glioneuronal tumors (DLGNTs) are rare central nervous system tumors of childhood that were recently described as a new entity. DLGNTs usually manifest with symptoms related to increased intracranial pressure or spinal cord compression. The classic radiological feature is a widespread leptomeningeal enhancement that may involve the entire neuroaxis. Microscopic examination demonstrates oligodendroglial-like cells that are positive for OLIG2, MAP2, and S100 and negative for IDH-1. Anaplastic features occur in some cases. Molecularly, DLGNTs are characterized by chromosome arm 1p deletion and alteration of a mitogen-activated protein kinase (MAPK) pathway gene, most commonly BRAF-KIAA1549 fusion. There is no established grading system for these tumors, which may have an indolent or aggressive behavior. Treatment usually involves chemotherapy and radiation therapy.

Diffuse Leptomeningeal Glioneuronal Tumor: A Rare Case Report with Review of Literature

Diffuse leptomeningeal glioneuronal tumor (DLGNT) is a rare tumor that was defined as a separate entity in the 2016 World Health Organization classification of brain tumors. It is most common in the pediatric age group. The diagnosis of this tumor can be made preoperatively by its characteristic imaging findings of diffuse intracranial and intraspinal nodular leptomeningeal thickening and enhancement associated with small cyst-like nonenhancing lesions in the brain and spinal cord. We report a case of DLGNT in a 7-year-old male presenting with hydrocephalus. The patient was treated successfully by cerebrospinal fluid (CSF) diversion followed by biopsy of the lesion from the cerebellum. Histopathology and immunohistochemistry confirmed the diagnosis of DLGNT. Our case would hopefully increase the awareness regarding this rare tumor and facilitate an early diagnosis and management of the affected patients with atypical radiological features.

Clinical progression, pathological characteristics, and radiological findings in children with diffuse leptomeningeal glioneuronal tumors: A systematic review

Background

Diffuse leptomeningeal glioneuronal tumors are rare leptomeningeal neoplasms composed of oligodendrocyte-like cells characterized by neuronal differentiation and a lack of isocitrate dehydrogenase gene mutation.

Purpose

We aimed to analyze the clinical progression, pathological characteristics, and radiological findings of diffuse leptomeningeal glioneuronal tumors in children, as well as the relevance of clinico-radiological data.

Data Sources

We searched MEDLINE, PubMed, and Web of Science to identify case reports, original articles, and review articles discussing diffuse leptomeningeal glioneuronal tumors published between 2000 and 2021.

Study Selection

The analysis included 145 pediatric patients from 43 previous studies.

Data Analysis

Data regarding patient pathology, MRI manifestations, clinical symptoms, and progression were collected. The relationship between imaging classification and pathological findings was using chi-square tests. Overall survival was analyzed using Kaplan–Meier curves.

Data Synthesis

Parenchymal tumors were mainly located in the intramedullary areas of the cervical and thoracic spine, and patients which such tumors were prone to 1p-deletion (χ2 = 4.77, p=0.03) and KIAA1549-BRAF fusion (χ2 = 12.17, p<0.001). The median survival time was 173 months, and the survival curve fell significantly before 72 months. Parenchymal tumor location was associated with overall survival (p=0.03), patients with KIAA 1549-BRAF (+) and treated with chemotherapy exhibited a better clinical course (p<0.001).

Limitations

The analysis included case reports rather than consecutively treated patients due to the rarity of diffuse leptomeningeal glioneuronal tumors, which may have introduced a bias.

Conclusions

Early integration of clinical, pathological, and radiological findings is necessary for appropriate management of this tumor, as this may enable early treatment and improve prognosis.

Uncommon Glioneuronal Tumors: A Radiologic and Pathologic Synopsis

Glioneuronal tumors are characterized exclusively by neurocytic elements (neuronal tumors) or a combination of neuronal and glial features (mixed neuronal-glial tumors). Most of these tumors occur in young patients and are related to epilepsy. While ganglioglioma, dysembryoplastic neuroepithelial tumor, and desmoplastic infantile tumor are common glioneuronal tumors, anaplastic ganglioglioma, papillary glioneuronal tumor, rosette-forming glioneuronal tumor, gangliocytoma, and central neurocytoma are less frequent. Advances in immunohistochemical and molecular diagnostics have improved the characterization of these tumors and favored the description of variants and new subtypes, some not yet classified by the World Health Organization. Not infrequently, the histologic findings of biopsies of glioneuronal tumors simulate low-grade glial neoplasms; however, some imaging findings favor the correct diagnosis, making neuroimaging essential for proper management. Therefore, the aim of this review was to present key imaging, histopathology, immunohistochemistry, and molecular findings of glioneuronal tumors and their variants.

Radiological Diagnosis of a Rare Prepontine Lesion: Ecchordosis Physaliphora

Ecchordosis physaliphora (EP) is a notochordal remnant tissue rarely encountered during routine clinical practice. These lesions usually do not produce any significant symptoms as they are slow-growing and mostly small in size. Symptoms are due to mass effects on adjacent structures when they are large or extra-tumoral hemorrhage. Because of histological similarity with chordoma, diagnosis is challenging, and this differentiation is essential as the disease course and treatment differ significantly. Imaging plays a crucial role in identifying and distinguishing these lesions.

We report the case of a 16-year-old male who presented with intermittent headache and neck pain for six months. His routine clinical examinations were within normal limits. On neurological assessment, there was no focal neurodeficit. Evaluation of cranial nerves did not reveal any evidence of palsy. Routine hematological tests were also normal. A computed tomography (CT) scan of the brain revealed a mass in front of the pons. Magnetic resonance imaging (MRI) for further evaluation revealed a T1 hypointense and T2/fluid-attenuated inversion recovery hyperintense lesion in the pre-pontine cistern. There was no enhancement in the mass either in the post-contrast CT or MRI scans. There was no bony erosion and clivus was normal. Based on the location and characteristic imaging features, a diagnosis of EP was made.

There may be several other lesions that may present as a mass in the pre-pontine region. Histopathological tests may find it difficult to distinguish between lesions that originate from notochord remnants. Imaging studies play a vital role in confirming the diagnosis and help in planning treatment and follow-up.

Diffuse leptomeningeal glioneuronal tumor without KIAA1549-BRAF fusion and 1p detection: a case report and review of literature

BACKGROUND

Diffuse leptomeningeal glioneuronal tumor (DLGNT) is a rare mixed neuronal-glial tumor of central nervous system. Chromosome microarray usually identifies co-deletion of the short arm of chromosome 1 and the long arm of chromosome 19 as well as fusion of the KIAA1549 and BRAF genes.

METHODS

We describe a case of a 3-year-old boy with typical imaging and histopathological features, but without KIAA1549-BRAF fusion and 1p deletion. Additionally, a literature review is performed summarizing the clinical features, management, and prognosis of this rare entity.

RESULTS

A 3-year-old boy presented with chronic headache and vomiting. On initial MRI scanning, diffuse thickening with enhancement of the cerebral and spinal leptomeninges could be detected after contrast injection. Multiple cystic lesions were found located on infratentorial leptomeninges, with progressive thickening of leptomeninges and increasing cysts on follow-up MRI after 9 months. Meningeal biopsy was carried out, showing that most of tumor cells were composed of oligodendroglioma-like cells. The tumor cells were immunopositive for GFAP, Olig-2, and synaptophysin but negative for IDH-1 and H3k27M. Molecular genetic testing did not detect KIAA1549-BRAF fusion, 1p deletion, or 1p/19q co-deletion. The patient was finally diagnosed as DLGNT after multidisciplinary team consultation.

CONCLUSIONS

Given that the clinical and pathological mechanism of DLGNTs remains unclear, our case gives supplement about the diversity of molecular genetic characteristics. Combination of clinical, neuroradiological, and histopathological data is particularly important for the diagnosis of DLGNTs, till now.

Pearls and Pitfalls of Imaging in Pediatric Brain Tumors

The central nervous system (CNS) tumors constitute the most common type of solid tumors in the pediatric population. The cerebral and cerebellar parenchyma are the most common site of pediatric CNS neoplasms. Imaging plays an important role in detection, characterization, staging and prognostication of brain tumors. The focus of the current article is pediatric brain tumor imaging with emphasis on pearls and pitfalls of conventional and advanced imaging in various pediatric brain tumor subtypes. The article also elucidates changes in brain tumor terms and entities as applicable to pediatric patients, updated as per World Health Organization (WHO) 2016 classification of primary CNS tumors. This classification introduced the genetic and/or molecular information of primary CNS neoplasms as part of comprehensive tumor pathology report in the routine clinical workflow. The concepts from 2016 classification have been further refined based on current research, by the Consortium to Inform Molecular and Practical Approaches to CNS Tumor Taxonomy (cIMPACT-NOW) group and published in the form of updates. The updates serve as guidelines in the time interval between WHO updates and expect to be broadly adopted in the subsequent WHO classification. The current review covers most pediatric brain tumors except pituitary tumors, meningeal origin tumors, nerve sheath tumors and CNS lymphoma/leukemia.

Emerging glioneuronal and neuronal tumors: case-based review

Glioneuronal and neuronal tumors (GNTs) are rare heterogeneous central nervous system tumors characterized by slow growth and favorable outcomes, but are often associated with diagnostic difficulties. A thorough analysis of three rare and recently recognized GNTs was performed in the context of clinicopathological features and molecular genetic characterization. The current spinal diffuse leptomeningeal glioneuronal tumor (DLGNT) was characterized with oligodendroglioma-like tumor with chromosome 1p/19q codeletion without IDH mutations and KIAA1549:BRAF fusion. The current occipital multinodular and vacuolating neuronal tumor (MVNT) was characteristic of the variable-sized vague nodules consisted of gangliocytic tumor cells with intracytoplasmic and pericellular vacuolation and the next-generation sequencing (NGS) revealed MAP2K1 p.Q56_V60del. A diffuse glioneuronal tumor with oligodendroglioma-like features and nuclear clusters (DGONC) of the amygdala was characterized by oligodendroglia-like cells and nuclear clusters, and monosomy 14. From the current cases and literature review, we found that DLGNT commonly occurs in the spinal cord and can make mass and more commonly have KIAA1549:BRAF fusion; MVNT is a neoplasm rather than malformation and MAP2K1 deletion is one of the hallmarks of this tumor; although DGONC may require a methylation profile, we can reach a diagnosis through its unique histology, monosomy 14, and exclusion diagnosis without a methylation profile.

A case of diffuse leptomeningeal glioneuronal tumor in a 10-year-old boy: First report from Iran

A 10-year-old boy who was referred due to acute hydrocephalus symptoms was diagnosed as the first case of pediatric DLGNT in Iran. The results suggested that using shunting for hydrocephaly and anti-seizure medicines, as well as chemotherapeutic agents, can be an effective treatment strategy for DLGNT. Although the patient was stable without a tumor recurrence for a limited follow-up period of 22 months, further studies are expected.

Ecchordosis physaliphora: Case report and brief review of the literature

Ecchordosis physaliphora is a rare congenital benign hamartomatous lesion originating from nodal cord remnants. This is histopathologically indistinguishable from chordoma, and hence imaging plays a key role in diagnosis. These lesions are hypointense on T1-weighted and hyperintense on T2-weighted images, and follow CSF signal. In contrast to chordoma, Ecchordosis Physaliphora does not demonstrate contrast enhancement. Here, we present a case of 32-year-old male with no prior medical history, who presented to an outside facility for chronic headache workup and incidentally detected indeterminate lytic defect in the bony clivus with a well demarcated smoothly corticated margin. Further assessment with MRI brain showed findings characteristic of Ecchordosis physaliphora, a benign congenital hamartomatous lesion originating from nodal cord remnants requiring no additional follow-up imaging or intervention.

The Pediatric Spine

The spine, a frequently investigated site in children, has a complex development in relation to both nervous and bone/cartilaginous structures and shows several particular features in children compared with adults. We report the main normal variants and pathologies of the pediatric spine, from the prenatal period to adolescence, focusing on a multimodality imaging approach.

Imaging of brain tumors in children: the basics-a narrative review

Primary pediatric brain tumors comprise a broad group of neoplasm subtypes that can be categorized based on their histological and molecular features according to the 2016 World Health Organization (WHO) classification of central nervous system (CNS) tumors. The majority of the pediatric brain tumors demonstrate a singular preference for this age group and have a unique molecular profile. The separation of certain tumor entities, including different types of embryonal tumors, low-grade gliomas, and high-grade gliomas, may have a significant impact by guiding appropriate treatment for these children and potentially changing their outcomes. Currently, the focus of the imaging diagnostic studies is to follow the molecular updates, searching for potential imaging patterns that translate this information in molecular profile results, therefore helping the final diagnosis. Due to the high impact of accurate diagnosis in this context, the scientific community has presented extensive research on imaging pediatric tumors in recent years. This article summarizes the key characteristics of the imaging features of the most common primary childhood brain tumors, categorizing them according to the recent WHO classification update, which is based on each of their molecular profiles. The purpose of this review article is to familiarize radiologists with their key imaging features and thereby improve diagnostic accuracy.

Case Report: Unusual High-Grade Diffuse Leptomeningeal Glioneuronal Tumor Mimicking Tuberculous Meningitis in a Child From an Endemic Region

Background: Diffuse leptomeningeal glioneuronal tumor (DL-GNT) is a new entity described in the 2016 World Health Organization (WHO) classification of brain tumors. While DL-GNT is predominantly an indolent tumor that affects young boys, high-grade DL-GNT is unusual and seldom reported in children. Case Presentation: In this report, we describe the challenges and pitfalls associated with diagnosing this high-grade variant in a tuberculosis-endemic region. We highlight the importance of identifying non-typical imaging findings, i.e., non-enhancing cystic lesions with high T2 signal along the leptomeningeal surface, that may expedite the diagnosis of this condition. Histopathologic correlations with MR spectroscopy findings are also discussed. Conclusion: We provide the first clinical imaging report of utilizing MR spectroscopy to distinguish DL-GNT from tuberculosis with histopathologic correlation.