- Special diagnosis: Patients presenting with rare intracranial neoplasms of low grade malignancy, but non-glial origin may be followed according to the low grade glioma strategy but they are not subject of this therapy trial. Their data may be registered however, to learn about those therapeutic interventions which may prove useful to these patients and to develop separate strategies in the future. Choroid plexus papilloma should be entered into the SIOP-CPT study.