In the last decades, many advances have been made in the field of genetic abnormalities of glial and glioneuronal brain tumors. In the 2016 World Health organization (WHO) Classification of Tumors of the Central Nervous System, the concept of "integrated" diagnosis emerged: histological and genetic/molecular features now define many entities. Since 2016, six updates have been published by the c-IMPACT-NOW (the Consortium to Inform Molecular and Practical Approaches to CNS Tumor Taxonomy- Not Official WHO) to develop and clarify the "integrated" diagnosis. In the future WHO 2021 Classification of Tumors of the Central Nervous System, "integrated" diagnoses will take up even more importance. Even if they can have similar histological features, gliomas of children are very different from the "adult" gliomas in the molecular mechanism of oncogenesis. The histomolecular features of adolescents/young adults (AYAs) can have similarities with "pediatric-type" or "adult-type" gliomas, but few studies have focused specifically on the histomolecular profiles of gliomas in AYAs.

The investigators would like to study the cohort of patients treated for a glial and glioneuronal tumor diagnosed under the age of 25 in the Amiens University Hospital between 2008 and 2020. The investigators would like to compare the histomolecular profiles of gliomas in children (0-14 years) and AYAs (15-25 years).

Inclusion Criteria:

• Male or female patient
• Patient treated in the Amiens University Hospital
• Patient treated for a glial or glioneuronal brain tumor according to the 2016 WHO Classification of Tumors of the Central Nervous System ("diffuse oligodendroglia or astrocytoma tumour," "another astrocytic tumor," "another glioma" or a "mixed neuronal or glioneuronal tumour").
• Diagnosis histologically confirmed or formally established by radiologist.
• Diagnosis established between January 1, 2008 and December 31, 2020.
• No patient opposition (from adult patient, or from the holder of parental authority of the minor patient).

Exclusion Criteria:

• Uncertain diagnosis
• Patient opposition (from adult patient, or from the holder of parental authority of the minor patient).

patients treated for a glial and glioneuronal tumor diagnosed under the age of 25 in the Amiens University Hospital between 2008 and 2020.