International Rare Brain Tumor Registry

Inclusion Criteria: * Patients with a known or suspected CNS Sarcoma. * Patients with a known or suspected BCOR-altered brain tumor * Patients with a known or suspected Astroblastoma/NM-1 altered brain tumor * Patients with known or suspected histologically ambiguous/unclassifiable brain tumor * Patients with a known or suspected rare brain tumor. * Signed informed consent by patient/ parent or guardian (assent where applicable) to participate in the study. Exclusion Criteria: * The patient has an extra-CNS primary tumor. * The patient is older than 46 years of age at diagnosis. * The patient or family is not willing to participate or does not sign informed consent.