Meningioma

Updated: Oct 05, 2022
  • Author: Georges Haddad, MD; Chief Editor: Stephen L Nelson, Jr, MD, PhD, FAACPDM, FAAN, FAAP, FANA  more...
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Overview

Practice Essentials

Meningioma refers to a set of tumors that arise contiguously to the meninges (see the image below). Meningiomas may occur intracranially or within the spinal canal. They are thought to arise from arachnoidal cap cells, which reside in the arachnoid layer covering the surface of the brain. 

Case 1: Surgical view of the tumor. The dura is op Case 1: Surgical view of the tumor. The dura is opened, and the meningioma can be seen extending en plaque over the surface of the brain.

Signs and symptoms

Meningiomas produce their symptoms by several mechanisms. They may cause symptoms by irritating the underlying cortex, compressing the brain or the cranial nerves, producing hyperostosis [1] and/or invading the overlying soft tissues, or inducing vascular injuries to the brain. [2]

Diagnosis

Imaging studies are the mainstay of diagnosis. Plain skull radiograph may reveal hyperostosis and increased vascular markings of the skull, as well as intracranial calcifications. On plain head CT scans, meningiomas are usually dural-based tumors that are isoattenuating to slightly hyperattenuating.

Management

In general, the ideal treatment of a benign meningioma is surgical resection if possible. 

Stereotactic radiosurgery has been shown to provide excellent local tumor control with minimal toxicity. [3, 4]

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Background

Meningioma, the term coined by Harvey Cushing, refers to a set of tumors that arise contiguously to the meninges (see the image below).

Case 1: Surgical view of the tumor. The dura is op Case 1: Surgical view of the tumor. The dura is opened, and the meningioma can be seen extending en plaque over the surface of the brain.

 

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Pathophysiology

Meningiomas may occur intracranially or within the spinal canal. They are thought to arise from arachnoidal cap cells, which reside in the arachnoid layer covering the surface of the brain. See the images below.

Case 1: MRI of a meningioma on plaque. Case 1: MRI of a meningioma on plaque.
Case 1: Bone-window CT reveals calcification of th Case 1: Bone-window CT reveals calcification of the meningioma.

Meningiomas commonly are found at the surface of the brain, either over the convexity or at the skull base. In rare cases, meningiomas occur in an intraventricular or intraosseous location. The problem of classifying meningioma is that arachnoidal cells may express both mesenchymal and epithelial characteristics. Other mesodermal structures also may give rise to similar tumors (eg, hemangiopericytomas or sarcomas). The classification of all of these tumors together is controversial. The current trend is to separate unequivocal meningiomas from other less well-defined neoplasms. Undoubtedly, advances in molecular biology will allow scientists to determine the exact genomic aberration responsible for each specific neoplasm.

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Epidemiology

Frequency

United States

The annual incidence of symptomatic meningiomas is approximately 2 cases per 100,000 individuals. Meningiomas account for approximately 20% of all primary intracranial neoplasms. However, the true prevalence is likely higher than this because autopsy studies reveal that 2.3% of individuals have undiagnosed asymptomatic meningiomas. Meningiomas are multiple in 5-40% of cases, particularly when they associated with neurofibromatosis type 2 (NF2). Familial meningiomas are rare unless associated with NF2. [5]

International

The frequency of meningiomas in Africa is nearly 30% of all primary intracranial tumors. [6]

Mortality/Morbidity

Mortality and morbidity rates for meningiomas are difficult to assess. Some meningiomas are discovered fortuitously when CT or MRI is done to assess for unrelated diseases or conditions. Therefore, some patients die with meningioma and not from it. Estimates of the 5-year survival usually range from 73-94%.

A systematic review of the literature regarding the clinical behavior of small, untreated meningiomas suggests that most meningiomas 2.5 cm or less in diameter do not proceed to cause symptoms in the 5 years following their discovery. Patients with tumors 2.5-3 cm in initial size went on to develop new or worsened symptoms 17% of the time. Those that do cause symptoms can usually be predicted with close radiographic follow-up. [7]

Meningiomas usually grow slowly, and they may produce severe morbidity before causing death.

Factors that may be predictive of a high postoperative morbidity rate include patient-related factors (eg, advanced age, comorbid states such as diabetes or coronary artery disease, preoperative neurological status), tumor factors (eg, location, size, consistency, vascularity, vascular or neural involvement), previous surgery, or previous radiation therapy.

Race

Meningiomas are more prevalent in Africa than in North America or Europe. In Los Angeles County, meningioma is reported more commonly in African Americans than in others.

Sex

Meningiomas afflict women more often than men. The male-to-female ratio ranges from 1:1.4 to 1:2.8.

  • The female preponderance may be less pronounced in the black population than in other groups.

  • Meningiomas are equally distributed between boys and girls.

Age

The incidence increases with age. Ages and corresponding incidence rates reported from 2002 are as follows:

  • Age 0-19 years - 0.12

  • Age 20-34 years - 0.74

  • Age 35-44 years - 2.62

  • Age 45-54 years - 4.89

  • Age 55-64 years - 7.89

  • Age 65-74 years - 12.79

  • Age 75-84 years - 17.04

  • Age 85 years and older - 18.86

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Prognosis

Patients whose meningiomas are completely resected usually have an excellent prognosis.

Tumor size may play a role in determining outcome. In a study of 34 patients who underwent surgery for CPA meningiomas, Agarwal et al found that the rate of permanent cranial nerve deficits was significantly greater in patients with tumors of more than 3 cm in size than in those with smaller meningiomas (45.5% vs 5.9%, respectively). It was also found that deficits of the lower cranial nerves occurred only in patients whose tumors extended into the jugular foramen. No association was found between tumor extension into the internal acoustic canal and either postoperative complications or cranial nerve deficits. Among all patients, 5.9% suffered postoperative facial nerve palsy. [8]

The following types of meningiomas are most likely to recur: incompletely excised, malignant, or multiple tumors.

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