A<unk>  that previously had been operated on, with surrounding edema MRI image of a<unk>  with contrast<unk> ta are visualized readily with contrast CT, MRI with gadolinium, and arteriography, all attributed to the fact that<unk> ta are extra-axial and vascularized. CSF protein levels are usually found to be elevated when lumbar puncture is used to obtain spinal fluid. On T1-weighted contrast-enhanced MRI, they may show a typical dural tail sign absent in some rare forms of<unk> s. Although the majority of<unk> ta are benign, they may have malignant presentations. Classification of<unk> ta are based upon the WHO classification system. * Benign (Grade I) – (90%) – meningothelial, fibrous, transitional, psammomatous, angioblastic * Atypical (Grade II) – (7%) – chordoid, clear cell, atypical (includes brain invasion) * Anaplastic/malignant (Grade III) – (2%) – papillary, rhabdoid, anaplastic (most aggressive) In a 2008 review of the latter two categories, atypical and anaplastic-meningioma cases, the mean overall survival for atypical<unk> ta was found to be 11.9 years vs. 3.3 years for anaplastic<unk> ta. Mean relapse-free survival for atypical<unk> ta was 11.5 years vs. 2.7 years for anaplastic<unk> ta. Malignant anaplastic<unk>  is aggressive. Although anaplastic<unk>  has higher chances of distant metastasis than the other two types, the overall incidence of<unk>  metastasis is only 0.18%; which is considered rare. Even if, by general rule, neoplasms of the nervous system (brain tumors) cannot metastasize into the body because of the blood–brain barrier, anaplastic<unk>  can. Although they are inside the cerebral cavity, they are located on the bloodside of the BBB, because<unk> ta tend to be connected to blood vessels. Thus, cancerized cells can escape into the bloodstream, which is why<unk> ta, when they metastasize, often turn up around the lungs. Anaplastic<unk>  and hemangiopericytoma are difficult to distinguish, even by pathological means, as they look similar, especially, if the first occurrence is a meningeal tumor, and both tumors occur in the same types of tissue. Although usually benign a "petro-clival"<unk>  is typically fatal without treatment due to its location. Until the 1970s no treatment was available for this type of<unk> ; however, since that time a range of surgical and radiological treatments have evolved. Nevertheless the treatment of this type of<unk>  remains a challenge with relatively frequent poor outcomes.
Meningioma
Metastasis
Glioma
Solitary fibrous tumor
Hemangioblastoma
Lymphoma
Astrocytoma
Schwannoma