Rare Neuronal, Glial and Glioneuronal Tumours in Adults

Simple Summary Glioneuronal and neuronal tumours are rare and mostly found in young adults and children, representing less than 5% of primary central nervous system (CNS) tumours. Accurate diagnosis is often difficult, requiring a significant body of evidence (clinical, radiological, pathology and molecular). The aim of this paper is to describe the main entities reported in the 2021 World Health Organization (WHO) classification, including, on the one hand, their histomolecular and imaging features and, on the other hand, their therapeutic management. Gross total resection is the cornerstone of the treatment of these tumours when achievable. MAPK pathway abnormalities could represent an interesting target for novel drugs. Rare glial, neuronal and glioneuronal tumours in adults form a heterogeneous group of rare, primary central nervous system tumours. These tumours, with a glial and/or neuronal component, are challenging in terms of diagnosis and therapeutic management. The novel classification of primary brain tumours published by the WHO in 2021 has significantly improved the diagnostic criteria of these entities. Indeed, diagnostic criteria are nowadays multimodal, including histological, immunohistochemical and molecular (i.e., genetic and methylomic). These integrated parameters have allowed the specification of already known tumours but also the identification of novel tumours for a better diagnosis.