Meningiomas are about one-fifth of all intracranial tumors, and depending on the type, are usually benign. They are slow-growing tumors that arise from the arachnoid granulations, which are one of the membranes that protect the brain. Meningiomas occur primarily in the 40-60 age group and are found slightly more often in women.
Approximately a quarter of patients with meningioma present with seizures – often with a focal component. In the remainder, the onset is insidious with pressure effects (headache, vomiting, visual difficulty) often occurring before other neurological signs become evident. Other neurological symptoms depend on the location of the tumor.
Meningiomas are usually well defined in CT scans and MRI imaging. Angiography may be conducted to identify whether there are any blood vessels tangled with the tumor that may have to be addressed before or during surgery.
Management of slow-growing tumors may involve monitoring by periodic MRI scanning. If surgery is recommended, the aim will be the complete removal of the tumor and the origin. With modern techniques, operative mortality has fallen to less than 5%, but varies depending on the position and size of the tumor. Recurrence of the tumor depends mostly on the completeness of removal. Malignant tumors have a higher rate of recurrence. Meningiomas recur in up to one-third of patients followed up for more than 10 years.