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Meningiomas
are benign tumors of the meninges that can compress adjacent brain
tissue. Symptoms depend on the tumor's location. Diagnosis is by
MRI with contrast agent. Treatment may include excision, stereotactic radiosurgery,
and sometimes radiation therapy.
Meningiomas, particularly those < 2 cm in diameter, are among the most common intracranial tumors. Meningiomas are the only brain tumor more common among women. These tumors tend to occur between ages 40 and 60 but can occur during childhood. These benign tumors can develop wherever there is dura, most commonly over the convexities near the venous sinuses, along the base of the skull, in the posterior fossa, and rarely within ventricles. Multiple meningiomas may develop. Meningiomas compress but do not invade brain parenchyma. They can invade and distort adjacent bone. There are many histologic types; all follow a similar clinical course, and some become malignant.
Symptoms
Symptoms depend on which part of the brain is compressed and thus on the tumor's location (see Table 3: Intracranial and Spinal Tumors: Symptoms of Meningiomas by Site ). Midline tumors in the elderly can cause dementia with few other focal neurologic findings.
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Table 3
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Symptoms of Meningiomas
by Site
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Site
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Findings
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Base of skull
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Visual loss
Oculomotor palsies
Exophthalmos
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Cerebral convexities
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Focal seizures
Cognitive deficits
Ultimately, signs of increased intracranial pressure
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Clivus and apical petrous bone
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Gait disturbance
Limb ataxia
Deficits referable to the 5th, 7th, and 8th cranial nerves
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Foramen magnum
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Ipsilateral suboccipital pain
Paresis that begins in the ipsilateral arm and progresses to the ipsilateral leg, then to the contralateral leg and arm
Sometimes Lhermitte's sign
Cranial nerve deficits (eg, dysphagia, dysarthria, nystagmus, diplopia, facial hypoesthesia)
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Olfactory groove
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Anosmia
Sometimes papilledema and visual loss
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Parasagittal or falx
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Spastic paresis or sensory loss, usually beginning in the contralateral leg, but occasionally bilateral
Cognitive deficits
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Posterior fossa tentorial tumors that extend superiorly or inferiorly
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Hydrocephalus
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Sphenoid wing:
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Medial (growing into the cavernous sinus)
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Oculomotor palsies
Facial numbness
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Middle (growing anteriorly into the orbit)
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Visual loss
Exophthalmos
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Lateral (as a globular mass or a *meningioma en plaque)
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Seizures
Headaches
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Tuberculum sellae
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Visual loss
Bony changes sometimes visible with imaging
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*Meningioma en plaque involves spread into the dura, with dural thickening and invasion of adjacent bone; the tumor sometimes grows into the temporal bone.
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Diagnosis
Diagnosis is similar to that of other brain tumors, usually by MRI with a paramagnetic contrast agent. Bony abnormalities (eg, brain atrophy, hyperostosis around the cerebral convexities, changes in the tuberculum sellae) may be seen incidentally on CT or plain x-rays.
Treatment
For asymptomatic small meningiomas, particularly in older adults, monitoring with serial neuroimaging. is sufficient.
Symptomatic or enlarging meningiomas should be excised if possible. If they are large, encroach on blood vessels (usually surrounding veins), or are close to critical brain areas (eg, brain stem), surgery may cause more damage than the tumor and is thus deferred.
Stereotactic radiosurgery is used for surgically inaccessible meningiomas and electively for other meningiomas. It is also used when tumor tissue remains after surgical excision or when patients are elderly.
If stereotactic radiosurgery is impossible or if a meningioma recurs, radiation therapy may be useful.
Last full review/revision February 2008 by William R. Shapiro, MD
Content last modified February 2008
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