Paediatric diffuse leptomeningeal tumor with glial and neuronal differentiation harbouring chromosome 1p/19q co-deletion and H3.3 K27M mutation: unusual molecular profile and its therapeutic implications.

Diffuse leptomeningeal glioneuronal tumor (DL-GNT) is a newly introduced tumor entity of uncertain prognosis characterised by a primary diffuse leptomeningeal growth pattern, oligodendroglial-like morphology and dual glial/neuronal differentiation. Predominantly occurring in children, these tumors present as chronic meningitis and mimic infectious/inflammatory diseases. They are surgically challenging tumors with a high incidence of delayed morbidity and mortality despite low-grade histology.