There are five types of meningioma: endothelial cell type, fibrous type or fibroblast type, hemangioma type, septic type and malignant meningioma. The endothelial cell type includes sandy meningioma, which is characterized by intra-tumor calcification forming sand-like bodies, and X-ray plain films can show calcified images of the tumor. Meningiomas are mostly benign, spherical or nodular in shape, and grow outside the brain parenchyma but are often embedded within the cerebral hemispheres. The most frequent sites of meningioma are the parsagittal sinus, the convexity of the brain, and the skull base (see Figure). The latter includes the pterygoid crest, olfactory groove, saddle nodes, and pontocerebellar horn, but rarely grows intracerebroventricularly. Meningiomas are extremely blood-rich, as the tumor often receives blood supply from multiple sources such as the external carotid artery, internal carotid artery, or vertebrobasilar artery. These tumors are very slow growing, so sometimes they may grow to a large size without showing symptoms. The clinical manifestations depend on the location of the tumor. If the tumor is located in the cerebral hemisphere, it often causes epilepsy, hemiparesis and mental disorders. If the tumor is located at the base of the skull, symptoms of cranial nerve and brain involvement are often seen in the corresponding area. Symptoms of increased intracranial pressure usually appear later. Patients may suffer from long-term chronic intracranial pressure increase, which may lead to loss of vision or even blindness in both eyes. Treatment The tumor should be completely removed and cured. However, if the tumor is particularly large or has involved important brain centers such as the lower thalamus and brainstem, as well as the carotid artery, basilar artery, or cranial nerves encapsulated in the tumor, surgery is sometimes difficult. Special care should be taken to stop bleeding and prevent injury to important nerves and blood vessels during surgery. Good surgical exposure is important for successful meningioma resection.