Meningiomas are very common, accounting for 15.31% of intracranial tumors, second only to gliomas. They are more common in adults, less common in older adults and children, and even less common in infants and children. They are slightly more common in women than in men. Meningiomas originate from the arachnoid endothelium, and all intracranial areas rich in arachnoid granules and arachnoid villi are good sites for meningiomas. Meningiomas are more common in the parsagittal sinus, cerebral convexity, and pars falcae, followed by the pterygoid crest, saddle node, olfactory groove, pontocerebellar horn, and cerebellar curtain, etc. They are rare in the ventricles and can also be seen in the epidural space. There are also ectopic meningiomas, occasionally seen in the skull plate, frontal sinus, subscalp of nasal cavity or neck, which are from ectopic arachnoid tissue, not metastasis. In addition, meningiomas can coexist with gliomas and neurofibromas in the skull, or with hemangiomas. The occurrence of meningioma may be related to certain internal environmental changes and genetic variants, and is not caused by a single factor. It may be associated with cranial trauma, radiation exposure, viral infection, and the combination of bilateral auditory neuroma. The prevalent sites are: ①sagittal sinus (about 50%), ②saddle node and pterygoid crest, ③sieve sinus, ④cavernous sinus, ⑤pontocerebellar horn, and ⑥cerebellar curtain. Classification According to their pathological characteristics, they are classified into the following types: endothelial or fibrous, vascular, gritty, mixed or migratory, malignant meningioma, and meningeal sarcoma. The first five are generally classified as benign meningiomas. Malignant meningioma occurs most frequently in angiogenic meningiomas, and multiple recurrences should also be considered as possible malignant changes. Growth characteristics of malignant meningioma The cell morphology has the characteristics of a malignant tumor with rapid growth. It can grow into the surrounding tissues and metastasize. Clinical manifestations Benign meningioma grows slowly and has a long course, with an average of about 2.5 years for the appearance of early symptoms and up to 6 years for the longest. 1. Common manifestations of intracranial occupying lesions: symptoms of increased intracranial pressure such as progressive headache, vomiting and optic papillar edema. 2. Most of them have irritation symptoms (such as epilepsy) first, followed by paralysis symptoms (such as paralysis). 3. The tumor grows slowly and has a long course; although the tumor is large, but the symptoms are light. 4. Different parts of tumor have different manifestations: brain convexity, sagittal sinus and parafalcine meningioma may have epilepsy, mental abnormality, weakness of limbs and aphasia, etc. Skull base meningioma (pterygoid crest, saddle node, pontocerebellar horn, slope, etc.), has corresponding localization symptoms. Meningiomas of the ventricular system, on the other hand, mainly present as intracranial hypertension. Meningioma imaging performance CT typical performance: with wide base near the skull or dura mater, there may be skull thickening, destruction or thinning. Most of them are high density, a few are isointense, and low density and mixed density are rare. The density is homogeneous, calcification may be present, the boundary is clear, and most of them have peritumoral edema. Enhancement scans have uniform and consistent enhancement, with marked density increase and sharp borders. MRI: Most meningiomas are low signal (T1-weighted) and high and equal signal (T2-weighted), and the signal is uniformly improved after injection of Gd-DTPA contrast agent; there is a low signal ring or band between the tumor and brain tissue; with peritumor edema, clearly showing the relationship between the tumor and blood vessels and venous sinuses. Treatment of meningioma 1.Surgical treatment: The treatment of meningioma is based on surgical resection. In principle, complete resection and removal of meninges and bone invaded by the tumor should be strived for, with a view to radical treatment. Meningioma is a tumor growing outside the parenchyma and most of them are benign. If it can be diagnosed early and operated before the tumor damages the surrounding brain tissues and important cranial nerves and blood vessels, it should be able to achieve the purpose of total resection. 2.Stereotactic radiotherapy (γ-knife, X-knife): It is suitable for small tumors in the midline area and skull base, with high surgical risk and not high intracranial pressure. 3.Interventional intravascular treatment: selective cannula is placed into the tumor blood supply artery and various emboli or sex hormone antagonists are injected to reduce tumor blood supply, promote tumor necrosis and inhibit tumor enlargement. Expert tips Meningioma is a benign tumor, which is difficult to detect in early stage due to slow growth, and the first symptom is still headache. Therefore, chronic headache patients should be alert to the occurrence of meningioma, and CT or MRI of the head can confirm the diagnosis. If the disease is treated aggressively, drugs are ineffective against the tumor, surgical removal of the tumor is the best method, and it is important to see a specialist and not to believe in rumors. Very few cases: such as midline or skull base small tumor, surgery is risky, γ-knife treatment can be used, but the efficacy is not sure. Endovascular intervention can be used as an adjuvant treatment.