ABSTRACT
Affecting the meninges, meningioma comprises 15 histological subtypes/variants that are organized into benign, atypical, and malignant categories. Benign meningioma is a slow-growing, noninvasive, and noncancerous neoplasm accounting for 65-80 percent of all meningiomas. Atypical meningioma is a fast-growing, moderately invasive neoplasm accounting for 15-20 percent of all meningiomas. Malignant meningioma is a fast-growing, aggressive, and cancerous neoplasm with a tendency to invade the surrounding brain tissue, recur, and metastasize extracranially. As the membranous coverings of the brain and spinal cord, the meninges are composed of three layers: the dura mater, arachnoid mater, and pia mater. Meningioma is the most common nonglial intracranial tumor and the second most common central nervous system (CNS) tumor in adults. Risk factors for meningioma are radiation exposure, NF2, female gender, oral contraceptives, and hormone replacement therapy. Given the clinical similarity between meningioma and normal aging, imaging techniques and histological investigation are required for confirmation of meningioma.
