<unk>  is a rare, fast-growing tumor that forms in one of the inner layers of the meninges (thin layers of tissue that cover and protect the brain and spinal cord).<unk>  often spreads to other areas of the body. The World Health Organization classification system defines both grade II and grade III<unk> s as<unk> . Historically, histological subtypes have also been used in classification including: * clear cell (WHO grade II), * chordoid (WHO grade II), * rhabdoid (WHO grade III), and * papillary (WHO grade III) Benign or low grade<unk> s (WHO grade I) include meningothelial, fibrous, transitional, psammomatous, angiomatous, microcystic, secretory, lymphoplasmacyte-rich, and metaplastic.
Malignant meningioma
Glioma
Meningioma
Astrocytoma
Glioblastoma
Gliosis
Anaplastic astrocytoma
Ameloblastoma