Meningioma
| Meningioma | |
|---|---|
 |
|
| A contrast-enhanced CT scan of the brain, demonstrating the appearance of a meningioma | |
| Classification and external resources | |
| Specialty | Neurosurgery |
| ICD-10 | C70, D32 |
| ICD-9-CM | 225.2 |
| ICD-O | M9530/0 |
| OMIM | 607174 |
| DiseasesDB | 8008 |
| eMedicine | neuro/209 radio/439 |
| Patient UK | Meningioma |
| MeSH | D008579 |
Meningiomas are a diverse set of tumors arising from the meninges, the membranous layers surrounding the central nervous system. Many meningiomas produce no symptoms throughout a person's life, and if discovered, require no treatment other than periodic observation. Typically, symptomatic meningiomas are treated with either radiosurgery or conventional surgery.
They arise from the arachnoid "cap" cells of the arachnoid villi in the meninges. These tumors are usually benign; however, a small percentage are cancerous. Historical evidence of meningiomas has been found going back hundreds of years, with some successful surgeries for their removal beginning in the 1800s.
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.
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. A 2012 review found that mobile telephone use was unrelated to meningioma.
People with neurofibromatosis type 2 (NF-2) have a 50% chance of developing one or more meningiomas.
Ninety-two percent of meningiomas are benign. Eight percent are either atypical or malignant.
The most frequent genetic mutations (~50%) involved in meningiomas are inactivation mutations in the neurofibromatosis 2 gene (merlin) on chromosome 22q.
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Wikipedia