Cerebellar NeoplasmsAstrocytomaOptic Nerve NeoplasmsHypothalamic NeoplasmsBrain NeoplasmsInfratentorial NeoplasmsCranial Nerve NeoplasmsGenes, Neurofibromatosis 1Neurofibromatosis 1Neurofibromin 1GliomaGlioblastomaOligodendrogliomaImmunohistochemistryThalamic DiseasesBrain Stem NeoplasmsOptic ChiasmEpendymomaAntineoplastic ProtocolsCentral Nervous System NeoplasmsHypothalamus, AnteriorProto-Oncogene Proteins B-rafCraniopharyngiomaSupratentorial NeoplasmsGangliogliomaAnaplasiaSpinal Cord NeoplasmsMagnetic Resonance ImagingTumor Markers, BiologicalMeningiomaImmunoenzyme TechniquesNeoplasm Grading