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

Abstract

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.

Diffuse Leptomeningeal Glioneuronal Tumour: An Intriguing Case Report of an Adult Patient with a Previous Optic Astrocytoma

“…Children represent the majority of cases with DLGT [3,4,12,14], however, the patient in this case report was 26 years old at the onset of the disease. The diagnosis of DLGT is often challenging, since patients present with non-specific symptoms of raised intracranial pressure with CSF analysis negative for tumour cells [14], which was also present in our instance In cases of DGLT, a high protein concentration in the CSF can be found, which is consistent with diffuse pial glial neuronal tumours and is due to tumour cells infiltration of the meninges, chemical stimulation of tumour metabolites, destruction of the bloodbrain barrier and increased vascular permeability [11]. Biopsy, histological analysis, and molecular genetic testing are crucial for diagnosing DLGT, as imaging findings are not specific enough and cases of DLGT have been misdiagnosed as tuberculosis [14,15].…”

“…Molecular and genetic testing, utilising NGS, is becoming an extremely important part of the diagnostic process, since there have been cases of DLGT without diffuse leptomeningeal involvement; a characteristic of the majority of DLGT [13]. Children represent the majority of cases with DLGT [3,4,12,14], however, the patient in this case report was 26 years old at the onset of the disease. The diagnosis of DLGT is often challenging, since patients present with non-specific symptoms of raised intracranial pressure with CSF analysis negative for tumour cells [14], which was also present in our instance In cases of DGLT, a high protein concentration in the CSF can be found, which is consistent with diffuse pial glial neuronal tumours and is due to tumour cells infiltration of the meninges, chemical stimulation of tumour metabolites, destruction of the bloodbrain barrier and increased vascular permeability [11].…”

“…The main aim of the therapy, at the present moment, is not a total resection of the tumour, as that is not feasible, but rather a reduction and when required, insertion of a ventriculoperitoneal shunt, if hydrocephalus occurs [12], as was present in this case. At present, no standardised treatment protocol has been developed for patients with DLGT, the majority are treated with a combination of surgery, chemotherapy and radiotherapy [14], however, targeted therapy and immunotherapy are also an option [11]. The majority of patients, who are treated with chemotherapy (systemic or intrathecal), receive a combination of temozolomide, carboplatin and vincristine [16]; the patient in our case report was administered carboplatin and vincristine systemically.…”

“…The diagnosis of DLGT is often challenging, since patients present with non-specific symptoms of raised intracranial pressure with CSF analysis negative for tumour cells [14], which was also present in our instance In cases of DGLT, a high protein concentration in the CSF can be found, which is consistent with diffuse pial glial neuronal tumours and is due to tumour cells infiltration of the meninges, chemical stimulation of tumour metabolites, destruction of the bloodbrain barrier and increased vascular permeability [11]. Biopsy, histological analysis, and molecular genetic testing are crucial for diagnosing DLGT, as imaging findings are not specific enough and cases of DLGT have been misdiagnosed as tuberculosis [14,15]. The imaging features indicating a case of DLGT are a prominent leptomeningeal enhancement with or without communicating hydrocephalus [15], which is due to the pronounced development of the tumour within the subarachnoid space [16].…”

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

“… 5 Due to its extremely low incidence, variable clinical presentation, nonspecific imaging findings, and variable symptomatology, DLGNT may be misdiagnosed, most often as infectious or inflammatory pathologies. 10 , 11 …”