A young man aged 20 years, with a history since the age of 6 of partial epileptic seizures with generalisation and poor drug control (at the time of his death he was being treated with oxcarbazepine), who died suddenly and unexpectedly during sleep. During his neurological check-up, he had undergone imaging studies of computed tomography (CT) and magnetic resonance imaging (MRI), which had shown no notable alterations.
A medico-legal autopsy was performed to clarify the cause of death. The neuropathological study revealed a brain weighing 1,545 grams with a brownish area measuring 0.5 x 1 cm in the cerebral cortex of the left parietal lobe, which showed no mass effect.

Histopathological study revealed a tumour exhibiting distinctive histopathological features, consisting of heterogeneous glioneuronal elements containing oligodendrocyte-like cells and floating neurons immersed in a myxoid interstitial fluid with a microcystic appearance. Immunohistochemical markers for glial fibrillary acidic protein (GFAP) and neuronal markers (enolase, neurofilaments and synaptophysin) were determined and were all positive. In view of these findings, the diagnosis of simple TDN was established.

The rest of the organs studied showed no notable morphological alterations (macroscopic or microscopic). The chemical-toxicological analysis was negative for the toxins analysed.

