Glioneuronal and other epilepsy-associated tumours

Abstract

Patients with (glio)neuronal brain tumours are rare. The most common variants, hat is, gangliogliomas and dysembryoplastic neuroepithelial tumours (DNTs), frequently present with pharmacoresistant epilepsy. Together with certain other tumour types associated with chronic epilepsy (including selected cases with diffuse gliomas WHO grade II/III) these entities have historically been referred to as LEATs (long-term epilepsy-associated tumours). LEATs share a very benign clinical course and rarely recur following a gross total resection. More than 80% of patients can expect to become seizure-free following epilepsy surgery (i.e. resection of the epileptogenic zone rather than tumour removal only). Hippocampal resections may improve the seizure outcome in cases with mesial temporal lobe epilepsy, but may also carry a concurrent risk of neuropsychological deficits. In contrast, oncological issues dominate the clinical course of LEATs and glioneuronal tumour variants if encountered outside the setting of refractory epilepsy. The dysplastic cerebellar gangliocytoma (L’Hermitte-Duclos disease, LDD) is the major central nervous system manifestation of Cowden disease. Its neoplastic nature is questionable.