Diffuse leptomeningeal glioneuronal tumour: where to biopsy? Case report and literature review

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.

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.

Case Report: Primary Diffuse Leptomeningeal Oligodendrogliomatosis in a Young Adult Cat

A 2-year-old cat was presented with progressive ataxia. Despite treatment the animal died. Pathomorphological examination revealed a widespread leptomeningeal mass at all levels of the central nervous system accentuated on the cervical spinal cord and the medulla oblongata without presence of a primary intraaxial tumor. The neoplasm was mainly composed of round, uninucleate cells with hyperchromatic nuclei, which were immunopositive for OLIG2, doublecortin, MAP2, synaptophysin, and vimentin, indicating components of both oligodendroglial and neuronal differentiation. Ki-67 immunohistochemistry indicated a high proliferation activity of the neoplasm. Few GFAP positive and Iba-1 positive cells were interpreted as reactive astrocytes and macrophages or microglia, respectively. The tumor was immunonegative for CD3, CD20, PAX5, MUM1, pan-cytokeratin, S100, NSE, p75^NTR, NeuN and periaxin. These findings led to the diagnosis of primary diffuse leptomeningeal oligodendrogliomatosis. This is the first reported case of this entity in a young cat, which should be considered as a differential diagnosis for diffuse subarachnoidal round cell infiltrates.