Meningiomas are typically surrounded by a collar of thickened dura mater. There is a peak incidence in the fifth and sixth decades. Meningiomas correspond histologically to Grade I. Anaplastic meningioma is extremely rare. Histologically, menigiomas constitute a heterogeneous group. The tumors show a tendency to concentric whorl formation.
Most lesions are homogeneously slightly hypodense to brain.
Total calcification is possible. Hyperostosis is frequent. On contrast enhanced CT, enhancement is typically homogeneous and intense. For this reason, in the early publications on MRI, it was said that meningiomas could easily be missed on non-enhanced images. A minority of the lesions are hypo- or hyperintense.