Meningiomas are neoplasms of meningothelial differentiation which can arise throughout the CNS. They are generally found in older adults with peak incidence in 60-70 year olds and most are sporadic. On imaging they often exhibit extension along the dura (dural tail). There are a 3 grades of meningioma as classified by the WHO - grade I (typical), II (atypical), III (anaplastic). Genetic risk factors include neurofibromatosis 2 and schwannomatosis. The clinical presentation of meningioma is location dependent but common symptoms are headache, seizures, visual changes, personality changes, and paresis. Treatment ranges from observation, surgery, to radiation. Most low grade meningiomas have good prognosis.

Meningioma exhibits many different histological subtypes, some of which are associated with higher grading. Clear cell and chordoid meningiomas are automatically classified as grade II, while rhabdoid and papillary ones are grade III. All the others are usually grade I in the absence of atypical features. Atypical features to look for include >=4 mitoses/10 hpf, brain invasion, or 3 of the following: small cell change, prominent nucleoli, spontaneous necrosis, hypercellularity, and patternless sheeting growth.

The psammomatous variant exhibits numerous psammoma bodies and the majority are grade I.