Diffuse leptomeningeal glioneuronal tumour (DLGNT) is a rare CNS neoplasm occurring in children and adolescents (1), originally recognised as a distinct entity in 2016. As the name implies, it has a striking predilection to the leptomeninges and, as such, is concentrated in the posterior fossa involving the cerebellum, followed closely by the spine.

Patients present with features of raised intracranial tension, like headache, vomiting, cranial nerve palsies, and papilledema, with CSF analysis showing elevated protein and lymphocytes.

On histopathology, the tumour consists of diffuse, multifocal leptomeningeal lesions with oligodendroglial-like cells scattered in a desmoplastic/myxoid background. Since it is a glio-neuronal tumour, IHC shows OLIG2-, S-10-0-, MAP2-positive oligodendroglial-like cells; astrocytes positive for GFAP; and neuronal cells positive for synaptophysin. 

We explore a set of cases with varied imaging manifestations of this uncommon neoplasm.