Pediatric Leptomeningeal Glial Tumors: A Retrospective Case Series and Review of the Literature

Objective: Diffuse leptomeningeal glioneuronal tumor (DLGNT), including primary diffuse leptomeningeal oligodendroglial tumors (PDLOs) and leptomeningeal spread of high-grade gliomas, are rare pediatric neoplasms with diffuse leptomeningeal dissemination and limited parenchymal involvement. Their often nonspecific neurological symptoms frequently lead to misdiagnosis as infectious or inflammatory meningitis, complicating early identification. Methods: To investigate these diagnostic challenges, the authors retrospectively reviewed the records of 4 pediatric patients (2-13 years) diagnosed with leptomeningeal glial tumors over a 5-year period. Clinical features, neuroimaging, cerebrospinal fluid (CSF) findings, histopathology, treatment, and outcomes were analyzed. Results: All patients had subacute or chronic neurological symptoms, including gait ataxia (4/4), motor weakness (3/4), headache or vomiting (3/4), cognitive or behavioral decline (3/4), and seizures (2/4). Cerebrospinal fluid abnormalities contributed to diagnostic confusion but were not identical across all cases: pleocytosis was present in all patients, elevated protein was documented in those with available protein measurements, and reduced or relatively low glucose was observed only in some patients. Magnetic resonance imaging (MRI) demonstrated diffuse leptomeningeal involvement along the neuraxis in all patients, with cystic/nodular T2-hyperintense lesions and variable enhancement. Three patients were diagnosed within the DLGNT/PDLO spectrum and 1 with high-grade glioma with leptomeningeal dissemination. Hydrocephalus requiring ventriculoperitoneal shunting developed in 3/4 patients. All received chemotherapy; 1 required decompressive spinal surgery and craniospinal radiotherapy. At last follow-up, 3 patients were alive with neurological sequelae and 1 had died of progressive disease. Conclusion: These findings highlight that pediatric leptomeningeal glial tumors are diagnostically challenging and easily mistaken for chronic meningitis. Characteristic MRI findings, elevated CSF protein, and spinal dissemination are important clues.