Meningioma

Meningioma, also known as meningeal tumor, is typically a slow-growing tumor that forms from the meninges, the membranous layers surrounding the brain and spinal cord. Symptoms depend on the location and occur as a result of the tumor pressing on nearby tissue. Many cases never produce symptoms. Occasionally seizures, dementia, trouble talking, vision problems, one sided weakness, or loss of bladder control may occur.

Risk factors include exposure to ionizing radiation such as during radiation therapy, a family history of the condition, and neurofibromatosis type 2. They appear to be able to form from a number of different types of cells including arachnoid cells. Diagnosis is typically by medical imaging.

If there are no symptoms, periodic observation may be all that is required. Most cases that result in symptoms can be cured by surgery. Following complete removal fewer than 20% recur. If surgery is not possible or all the tumor cannot be removed, radiosurgery may be helpful. Chemotherapy has not been found to be useful. A small percentage grow rapidly and are associated with worse outcomes.

About one per thousand people in the United States are currently affected. Onset is usually in adults. In this group they represent about 30% of brain tumors. Women are affected about twice as often as men. Meningiomas were reported as early as 1614 by Felix Plater.

Small tumors (e.g., < 2.0 cm) usually are incidental findings at autopsy without having caused symptoms. Larger tumors may cause symptoms, depending on the size and location.^{[citation needed]}

The causes of meningiomas are not well understood. Most cases are sporadic, appearing randomly, while some are familial. Persons who have undergone radiation, especially to the scalp, are more at risk for developing meningiomas, as are those who have had a brain injury. Atomic bomb survivors from Hiroshima had a higher than typical frequency of developing meningiomas, with the incidence increasing the closer that they were to the site of the explosion. Dental X-rays are correlated with an increased risk of meningioma, in particular for people who had frequent dental X-rays in the past, when the X-ray dose of a dental X-ray was higher than in the present.

Having excess body fat increases the risk. In 2020, the European Medicine Agency issued a warning that high doses of cyproterone acetate may contribute to risk of meningioma, and to use the minimum dosage or alternative treatment for most indications, with the exception of prostate carcinoma.

A 2012 review found that mobile telephone use was unrelated to meningioma.