Meningioma accounts for 14.4%–19.0% of intracranial primary tumors. It is an extra-axial tumor, typically benign, and originates from the arachnoid. The average age of onset is 45 years, with a male-to-female ratio of 1:1.8. It is rare in children. Approximately 60%–70% of cases are located near the sagittal sinus, cerebral convexity, sphenoid bone, or tuberculum sellae. Multiple meningiomas occur in 8% of cases, often in patients with neurofibromatosis. Malignant meningiomas are less common, grow in an infiltrative manner, lack clear boundaries with brain tissue, cause severe cerebral edema, and may metastasize to the lungs.
On CT scans, meningiomas generally exhibit homogeneous density and may present with or without calcifications or cerebral edema. The tumor often has a broad base and is commonly attached to the dura mater. Post-contrast imaging frequently shows significant tumor enhancement. On MRI, T2-weighted images can display the tumor and the patency of dural sinuses, while post-contrast imaging may reveal the "dural tail sign."
The majority of meningiomas can be cured with complete surgical resection, although complete removal may not always be feasible. Incidentally discovered, asymptomatic small meningiomas, particularly in elderly patients, may be monitored with regular MRI follow-ups, as immediate surgery may not be necessary; some tumors may gradually cease growing. For malignant meningiomas (WHO Grade 3) and recurrent atypical meningiomas (WHO Grade 2), radiotherapy may be considered.