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. As of 2014 they do not appear to be related to cell phone use. 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. Meningiomata were reported as early as 1614 by Felix Plater. Signs and symptoms
Small tumors (e.g., < 2.0 cm) usually are incidental findings at autopsy without having caused symptoms.
As such, they also have a tendency to calcify and are highly vascularized.Meningiomata often are considered benign tumors that can be removed by surgery, but most recurrent meningiomata correspond to histologic benign tumors. The metabolic phenotype of these benign recurrent meningiomata indicated an aggressive metabolism resembling that observed for atypical meningioma. Diagnosis
Meningiomata are visualized readily with contrast CT, MRI with gadolinium, and arteriography, all attributed to the fact that meningiomata are extra-axial and vascularized. CSF protein levels are usually found to be elevated when lumbar puncture is used to obtain spinal fluid. On T1-weighted contrast-enhanced MRI, they may show a typical dural tail sign absent in some rare forms of meningiomas.Although the majority of meningiomata are benign, they may have malignant presentations. Classification of meningiomata are based upon the WHO classification system. Benign (Grade I) – (90%) – meningothelial, fibrous, transitional, psammomatous, angioblastic
Atypical (Grade II) – (7%) – chordoid, clear cell, atypical (includes brain invasion)
Anaplastic/malignant (Grade III) – (2%) – papillary, rhabdoid, anaplastic (most aggressive)In a 2008 review of the latter two categories, atypical and anaplastic-meningioma cases, the mean overall survival for atypical meningiomata was found to be 11.9 years vs. 3.3 years for anaplastic meningiomata. Mean relapse-free survival for atypical meningiomata was 11.5 years vs. 2.7 years for anaplastic meningiomata.Malignant anaplastic meningioma is aggressive. Although anaplastic meningioma has higher chances of distant metastasis than the other two types, the overall incidence of meningioma metastasis is only 0.18%; which is considered rare.