Diffuse leptomeningeal glioneuronal tumor
Ventricular dilatation and CSF transudation are present and CSF flow artifact is demonstrated at the foramen of Monro, cerebral aqueduct and foramina of Luschka. Features here are of communicating hydrocephalus.
There is widespread leptomeningeal enhancement. There is nodular leptomeningeal disease that extends around the upper cervical cord.
Biopsy of abnormal meningeal tissues from around the base of the brain was performed and revealed a highly cellular malignant process. The final report confirmed this to be diffuse leptomeningeal glioneuronal tumor (also known as disseminated oligodendroglial-like leptomeningeal tumor of childhood), a relatively recently described tumor only added to the WHO classification of CNS tumors in the 2016 update.