LAUSR

A 6-year-old boy, with an unremarkable birth history and developmental history notable only for intellectual disability, developed expressive aphasia and intermittent vomiting in 3 weeks. Brain MRI showed communicating hydrocephalus and characteristic diffuse subpial cystic lesions throughout the surface (Figure). His symptom of vomiting was relieved after he was given a ventricular-peritoneal shunt (valve pressure set as 140 mm H2O) and meningeal-cortical biopsy. The final diagnosis was diffuse leptomeningeal glioneuronal tumor, a new entity in the 2016 WHO classification of CNS tumors.1 He was referred to a local oncology center because chemotherapy had been proposed as first-line treatment.2