Unusual radiological and histological presentation of a diffuse leptomeningeal glioneuronal tumor (DLGNT) in a 13-year-old girl

Diffuse leptomeningeal glioneuronal tumor in a child masquerading as an intramedullary spinal pilocytic astrocytoma

Diffuse leptomeningeal glioneuronal tumor (DLGNT) occurs predominantly in children and is typically characterized by diffuse leptomeningeal lesions throughout the neuroaxis with focal segments of parenchymal involvement. Recent reports have identified cases without diffuse leptomeningeal involvement that retain classic glioneuronal features on histology. In this report, we present a case of a 4-year-old boy with a large cystic-solid intramedullary spinal cord lesion that on surgical biopsy revealed a biphasic astrocytic tumor with sparsely distributed eosinophilic granular bodies and Rosenthal fibers. Next-generation sequencing revealed a KIAA1549-BRAF fusion, 1p/19q codeletion, and lack of an IDH1 mutation. Methylation profiling demonstrated a calibrated class score of 0.98 for DLGNT and copy number loss of 1p. Despite the morphologic similarities to pilocytic astrocytoma and the lack of oligodendroglial/neuronal components or leptomeningeal dissemination, the molecular profile was definitive in classifying the tumor as DLGNT. This case highlights the importance of molecular and genetic testing in the characterization of pediatric central nervous system tumors.

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.

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

BACKGROUND

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).

MATERIAL AND METHODS

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.

RESULTS

We included 34 reports in our review comprising 63 patients, published from 2016 to 2022. The median OS was 19 months (range: 12-51 months). Using multivariable Cox survival analysis, we showed that Ki-67 ≥ 7%, age > 9 years, 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.

CONCLUSIONS

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.

Atypical and aggressive diffuse leptomeningeal glioneuronal tumor in a young adult: A case report and review of the literature

Background

DLGNT is a rare tumor, commonly diagnosed in pediatric age; in most cases, the pathology presents a slow and indolent evolution. We present a case report of a young adult affected by DLGNT characterized by aggressive and atypical behavior.

Case Description

A 21-year-old male presented with mild paraparesis and hypoesthesia with a D2 level. MRI scan of the brain and spine showed a dorsal intramedullary lesion; a diffuse craniospinal leptomeningeal thickening was also present. After a week, the neurological status deteriorated rapidly with paraparesis worsening and onset of acute hydrocephalus. The patient underwent external ventricular drain positioning; a C7-D4 laminectomy was subsequently performed with partial tumor resection. Histological examination revealed a DLGNT with aggressive aspects (Ki67 30%). Postoperatively, the patient showed an immediate mild worsening of the lower limbs deficit. After a few days, severe further neurological deterioration occurred with progressive motor deficit to the upper limbs and ultimately respiratory failure. Mechanical ventilation was necessary and the patient was transferred to the ICU; during the following weeks, he developed tetraplegia and underwent ventriculoperitoneal shunt positioning. By the time, the histological diagnosis was available, the clinical status would not allow radiotherapy or chemotherapy. The patient deceased approximately 90 days after hospitalization due to respiratory complications.

Conclusion

DLGNT is a rare tumor; diagnosis requires a high index of suspicion and confirmation with biopsy. Although most cases have an indolent course, some patients may have aggressive forms. High proliferation index, hydrocephalus occurrence, and massive craniospinal leptomeningeal spread appear to be associated with worse prognosis.

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.

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.

Diffuse leptomeningeal glioneuronal tumour (DLGNT) in children: the emerging role of genomic analysis

Diffuse leptomeningeal glioneuronal tumours (DLGNT) represent rare enigmatic CNS tumours of childhood. Most patients with this disease share common radiological and histopathological features but the clinical course of this disease is variable. A radiological hallmark of this disease is widespread leptomeningeal enhancement that may involve the entire neuroaxis with predilection for the posterior fossa and spine. The classic pathologic features include low- to moderate-density cellular lesions with OLIG2 expression and evidence of ‘oligodendroglioma-like’ appearance. The MAPK/ERK signaling pathway has recently been reported as a potential driver of tumourigenesis in up to 80% of DLGNT with KIAA1549:BRAF fusions being the most common event seen. Until now, limited analysis of the biological drivers of tumourigenesis has been undertaken via targeted profiling, chromosomal analysis and immunohistochemistry. Our study represents the first examples of comprehensive genomic sequencing in DLGNT and shows that it is not only feasible but crucial to our understanding of this rare disease. Moreover, we demonstrate that DLGNT may be more genomically complex than single-event MAPK/ERK signaling pathway tumours.

Spinal Cord Diffuse Leptomeningeal Glioneuronal Tumor Presenting without Leptomeningeal Dissemination

BACKGROUND AND IMPORTANCE

Diffuse leptomeningeal glioneuronal tumor (DLGNT) represents a provisional entity in the 2016 World Health Organization classification of tumors; it is characterized by a widespread leptomeningeal growth and oligodendroglial-like cytology. To this day, 4 pediatric patients have been reported to present with an isolated spinal cord tumor in the absence of leptomeningeal dissemination. Gross total resection (GTR) was achieved in only 1 patient. We present the clinical and technical nuances of this unique type of tumor, as well as the second reported case of GTR in a patient with DLGNT.

CLINICAL PRESENTATION

A 4-year-old boy presented to the emergency department after an episode of flaccid paralysis of bilateral lower extremities. MRI showed an intramedullary spinal cord tumor centered at T8. The patient was taken to the operative room, where a laminectomy and tumor resection were performed; cystic and solid tumor components were identified. Pathology report was consistent with DLGNT. After achieving GTR, patient is free of recurrence after a 15-month follow-up.

CONCLUSION

No standard treatment for DLGNT has been identified. Current literature report surgery and chemotherapy with variable success rates. DLGNT presenting as an isolated intramedullary tumor is an uncommon condition which progression appears to be halted when treated promptly. Identifying solid and cystic components of this tumor is crucial for achieving GTR.

Diffuse Leptomeningeal Glioneuronal Tumor in a 4.5-year-old Girl: A Case Report and Review of the Literature

Diffuse leptomeningeal glioneuronal tumor (DLGNT) is an entity introduced in 2016 World Health Organization classification of tumors of the central nervous system. The tumor occurs very rarely. Due to the lack of specific clinical and radiological features, biopsy is necessary to be performed and histological and immunohistochemical testing is essential to reach the diagnosis. A 4.5-year-old girl presented with a history of headache, vomiting, and right eye convergent squint. Imaging revealed multiple enhancing lesions located supra- and infratentorially and intramedullary. Histopathological examination demonstrated diffused growth of neoplastic cells. Molecular testing revealed KIAA1549-BRAF fusion and the diagnosis of DLGNT was stated.

Diffuse leptomeningeal glioneuronal tumor: a double misnomer? A report of two cases

Diffuse leptomeningeal glioneuronal tumor (DLGNT) was introduced, for the first time, as a provisional entity in the 2016 WHO classification of central nervous system tumors. DLGNT mainly occur in children and characterized by a widespread leptomeningeal growth occasionally associated with intraspinal tumor nodules, an oligodendroglial-like cytology, glioneuronal differentiation and MAP-Kinase activation associated with either solitary 1p deletion or 1p/19q codeletion in the absence of IDH mutation.

We report here two unexpected DLGNTs adult cases, characterized by a unique supratentorial circumscribed intraparenchymal tumor without leptomeningeal involvement in spite of long follow-up. In both cases, the diagnosis of DLGNT was made after DNA-methylation profiling which demonstrated that one case belonged to the DLGNT class whereas the other remained not classifiable but showed on CNV the characteristic genetic findings recorded in DLGNT. Both cases harbored 1p/19q codeletion associated with KIAA1549:BRAF fusion in one case and with BRAF V600E and PIK3CA E545A mutations, in the other.

Our study enlarges the clinical and molecular spectrum of DLGNTs, and points out that the terminology of DLGNTs is not fully appropriate since some cases could have neither diffuse growth nor leptomeningeal dissemination. This suggests that DLGNTs encompass a wide spectrum of tumors that has yet to be fully clarified.

Imaging of Neuronal and Mixed Glioneuronal Tumors

Neuronal and mixed glioneuronal tumors represent a group of neoplasms with varying degrees of neural and glial elements. Their age of presentation varies, but they are most commonly seen in children and young adults. With the exception of anaplastic ganglioglioma and other atypical variants, most lesions are low grade; however, they can have significant morbidity because of seizures, mass effect, or difficult to treat hydrocephalus. Although many tumors show overlapping clinical and imaging features, some have relatively distinctive imaging characteristics that may aid in narrowing the differential diagnosis. In this review, we discuss relevant clinical and pathologic characteristics of these tumors and provide an overview of conventional and advanced imaging features that provide clues as to the diagnosis.

Diffuse leptomeningeal glioneuronal tumour (DLGNT) with hydrocephalus as an initial symptom: a case-based update

PURPOSE

Diffuse leptomeningeal glioneuronal tumour (DLGNT) is a rare disease classified in 2016. There are different views of the clinical, pathologic and neuroradiologic characteristics of DLGNT due to the minor studies on this disease.

METHODS

We describe a case of a 12-year-old boy who initially presented intermittent headache, vomiting and communicating hydrocephalus. A literature review is also presented summarizing the clinical characteristics and treatments of DLGNT.

RESULTS

In our case, a ventriculoperitoneal shunt was applied to reduce intracranial pressure caused by communicating hydrocephalus. T1-weighted contrast-enhanced magnetic resonance imaging (MRI) showed linear enhancement, and microscopy showed tumour-like spindle cells. The diagnosis of DLGNT was confirmed, and temozolomide was administered. The clinical characteristics were similar in the reported cases, while the treatments showed differences.

CONCLUSION

Ventriculoperitoneal shunts are effective for patients with hydrocephalus-related intracranial hypertension. Chemotherapy including temozolomide has shown varying outcomes, and further studies are expected.

Diffuse Leptomeningeal Glioneuronal Tumor: A Unique Leptomeningeal Tumor Entity

BACKGROUND

Diffuse leptomeningeal glioneuronal tumor (DLGNT) is a recent addition to the World Health Organization classification schema of brain tumors, under the heading of neuronal and mixed neuronal-glial tumors. DLGNTs have a classic imaging appearance. However, it has often been misdiagnosed owing to its rarity, its resemblance to granulomatous/leptomeningeal etiologies, and the clinical presentation.

CASE DESCRIPTION

We have described the case of a 3-year-old girl who had presented with complaints of nonprojectile vomiting and altered sensorium that had been initially diagnosed and treated as a case of tubercular meningitis at a peripheral health facility. However, the nonresponse to antitubercular medication necessitated a repeat magnetic resonance imaging evaluation at our institute, which had revealed the classic imaging appearance of DLGNT. The diagnosis was further established by meningeal biopsy and the histopathological evaluation findings.

CONCLUSION

We have described the classic imaging appearance of this rare brain tumor. Radiologists and clinicians should be aware of this entity to avoid misdiagnosis and a delay in management.