bubble_chart Overview

Meningiomas are very common, accounting for 15.31% of intracranial tumors, second only to gliomas. They are more prevalent in adults, less common in the elderly and children, and rare in infants. Females are slightly more affected than males. Meningiomas originate from the endothelial cells of the arachnoid membrane. Any intracranial areas rich in arachnoid granulations and arachnoid villi are prone to meningioma development. Common sites include the parasagittal sinus, cerebral convexity, and falx cerebri, followed by the sphenoid ridge, tuberculum sellae, olfactory groove, cerebellopontine angle, and tentorium cerebelli. Intraventricular growth is rare, but they can also occur outside the dura mater. Ectopic meningiomas are occasionally found in the diploë of the skull, frontal sinus, subcutaneous tissue of the nasal cavity or scalp, or neck, arising from ectopic arachnoid tissue rather than metastasis. Multiple meningiomas account for about 1-2% of cases, with as many as dozens scattered in the same area, including one large tumor nodule and several smaller ones, ranging in size from walnuts to millet grains. Supratentorial meningiomas are far more common than infratentorial ones. Additionally, meningiomas can coexist with gliomas or neurofibromas in the intracranial space and may also occur alongside hemangiomas.

bubble_chart Clinical Manifestations

A brain membrane tumor is a slowly growing neoplasm. Like other extra-axial brain tumors, its symptoms arise from compression of adjacent brain tissues and cranial nerves rather than tumor infiltration. Additionally, the large tumor mass can affect cerebral venous return or obstruct cerebrospinal fluid circulation and absorption, leading to symptoms of increased intracranial pressure, including headache and visual disturbances. In advanced stages, it may cause bilateral blindness.

Brain membrane tumors in different locations can involve nearby neural tissues, resulting in corresponding neurological deficits or irritative symptoms. Those in the central sulcus region often cause epilepsy and contralateral incomplete hemiplegia; frontal lobe and anterior cranial fossa tumors may present with psychiatric symptoms. Medial sphenoid ridge and tuberculum sellae tumors typically induce early vision loss, sometimes accompanied by visual field defects. Cerebellopontine angle tumors manifest symptoms of cranial nerves V, VI, VII, and VIII damage along with cerebellar dysfunction, resembling acoustic neuromas. Tumors in functionally silent areas (so-called "silent regions") may remain asymptomatic for long periods, with some only discovered during autopsy. Intraventricular brain membrane tumors tend to disrupt cerebrospinal fluid circulation, causing increased intracranial pressure without obvious neurological deficits.

bubble_chart Diagnosis

The clinical characteristics of meningioma are slow onset and long duration. Meningiomas in different locations may present with varying clinical manifestations. Since the disease is more common in adults, any adult presenting with chronic headache, mental changes, epilepsy, unilateral or bilateral visual impairment or even blindness, ataxia, or localized skull masses—especially when accompanied by progressively worsening symptoms of increased intracranial pressure—should be considered for the possibility of meningioma. Fundus examination often reveals chronic optic disc edema or secondary atrophy.

The definitive diagnosis of the tumor still relies on auxiliary diagnostic tests. Examinations of significant reference value for diagnosing meningioma include skull radiographs, CT scans, and cerebral angiography. These not only help localize the tumor but also provide information on its size and nature.

1. Skull radiographs: Intracranial meningiomas require routine skull radiographs. Approximately 75% of cases show signs of intracranial tumors on plain films, and 30–60% of cases can be diagnosed as meningiomas based on radiographic findings. Some signs on X-ray skull radiographs are indirect indicators of intracranial tumors and increased intracranial pressure, such as erosion and enlargement of the sella turcica, prominent convolutional markings, and displacement of calcified pineal gland. In rare cases, cranial suture separation may occur. Another set of signs is directly caused by meningiomas, including local bone hyperplasia and destruction, widened and increased vascular grooves due to increased tumor blood supply, tumor calcification, and local bone thinning. These features often serve as reliable diagnostic criteria for meningiomas.

2. CT scans: In the diagnosis of meningiomas, CT scans have replaced isotopic brain scans, pneumoencephalography, and ventriculography. Meningiomas are mostly solid and highly vascularized, making them particularly suitable for CT examination, which can accurately detect meningiomas as small as 1 cm. On CT scan images, meningiomas exhibit distinctive features, showing a localized, round, uniformly dense contrast-enhanced image within the skull, possibly accompanied by bone hyperplasia. A low-density edema zone may appear around the tumor, along with corresponding brain displacement and signs of hydrocephalus due to cerebrospinal fluid circulation obstruction.

3. Cerebral angiography: For certain meningiomas, cerebral angiography remains necessary, especially for deep-seated meningiomas with multi-source blood supply. Only through cerebral angiography can the tumor's blood supply sources, vascularity, and adjacent vascular distribution be understood. These details are crucial for surgical planning, including the selection of surgical approaches and methods. If selective external carotid artery, internal carotid artery, and vertebral artery angiography can be performed—particularly using digital subtraction angiography—the vascular changes will be even clearer and more definitive.

Additionally, lumbar puncture can reflect increased intracranial pressure and elevated cerebrospinal fluid protein levels, which still hold certain reference value in diagnosis and differential diagnosis.

bubble_chart Treatment Measures

The primary treatment for meningioma is surgical resection. In principle, complete resection should be pursued, including the removal of the meninges and bone invaded by the tumor to achieve a cure. Meningiomas are extra-axial tumors, mostly benign. If diagnosed early and operated on before the tumor damages surrounding brain tissue, critical cranial nerves, or blood vessels, total resection is often achievable. However, in some advanced-stage tumors, especially deep-seated meningiomas, the tumor may be large and tightly adhered to nerves, blood vessels, the brainstem, or the hypothalamus, or may encase these structures, making separation difficult. In such cases, attempting total resection is not advisable, as it may increase the risk of brain and cranial nerve injury, intraoperative hemorrhage, or even lead to patient death or severe disability. Instead, subtotal resection to reduce tumor volume, combined with decompressive surgery, can alleviate pressure on the brain, relieve intracranial pressure (e.g., in hydrocephalus), and preserve vision. Alternatively, staged surgery may be considered. For truly inoperable advanced-stage tumors, a biopsy followed by decompressive surgery may prolong life. Malignant cases may benefit from adjuvant radiotherapy.