Originating from non-central nervous<unk>  tissue These classification of<unk> s are embedded in the endoderm (inner layer) and the ectoderm (outer layer) of the cranial or spinal cord germ layers. They normally take over the neuraxis, the axis of the central nervous<unk>  that determines how the nervous<unk>  is placed, which allows the<unk> s to infiltrate the CNS tissues. They are most commonly found in the area near the pineal gland, the chiasmatic cistern, and the cerebellopontine angle space. These common places generally house extensive and continuously growing<unk> s. Some examples of<unk> s originating from non-central nervous<unk>  tissue include: * Teratomas<unk> s (containing multiple body tissue types) * Dermoid (epidermoid/epidermoid tumor) * Rathke's cleft<unk> s * Pineal<unk> s * Tumor-associated<unk> s * Epithelial<unk> s that originate from upper respiratory and intestinal tracks. Originating from the central nervous<unk>  tissue Human brain showing a colloid<unk>  in the third ventricle This category of<unk> s takes over areas of necrotic tissue in the brain from injuries, diseases, or abnormalities, which occur due to the central nervous<unk> 's nonregenerative nature. These<unk> s can affect all germ layers of the CNS, but are most common in the arachnoid mater, and the ventricular space, which may block CSF pathways. These<unk> s can be static (stationary) or progressive. Some examples of<unk> s originating from the CNS tissue include: * Arachnoid<unk> s (Leptomeningeal<unk> s) * Ependymal<unk> s *<unk> ic cerebellar astrocytomas * Colloid<unk> s
Central nervous system cyst
Glial tumor
Chiari malformation
Brain metastasis
Choroid plexus tumor
Brain stem tumor
Primary central nervous system lymphoma
Central nervous system cavernous hemangioma