Etiology The exact etiology of intracranial tumors is not yet fully understood. The possible causative factors are: 1. oncogenes and genetic factors Molecular biology of tumors shows that there are two types of genes closely related to tumor occurrence and development. The activation and overexpression of oncogenes induce tumor formation, while the presence and expression of anti-oncogenes help to inhibit tumor occurrence. Cells with oncogenes do not always develop tumors and need to undergo repeated and multiple provocations of various kinds to cause small cell evolution. Biological, chemical and physical stimuli such as viruses, X-rays, and oncogenic chemicals can prompt oncogenes on cell chromosomes to cause cells to proliferate uncontrollably and form malignant tumors of varying degrees. Neurofibromatosis, angioretinal cell tumor and retinoblastoma have obvious tendency to develop in families. 2.Physical factors Radiation can increase the incidence of tumor, and the amount of radiation is more than 30Gy. It can be explained by “double strike” theory, radiation is the second strike factor, which can cause the oncogene of cells to mutate again and lead to intercellular changes. Chemical factors Chemical factors include anthracene compounds, among which methylcholanthrene is likely to induce glioma. Benzanthrene is likely to induce pituitary tumor. Methylnitrosamines and ethylnitrosamines are very strong carcinogens, especially to the central nervous system. Among them, ethylnitrosourea is particularly susceptible to carcinogenic effects in the perinatal period. 4.Tumor-causing virus After invading cells, the virus is fixed in the chromosome during the cell proliferation S period of DNA synthesis in the nucleus, which changes the genetic characteristics and promotes uncontrolled proliferation. Clinical manifestations 1. The onset of the disease is often slow, and the course of the disease can vary from 1 to 2 months to several years. Some cases may have acute or subacute onset and may even present with stroke. Most of the latter cases are due to the high malignancy of the tumor, rapid progression, or secondary changes such as hemorrhage, necrosis and cystic transformation. 2.Increased intracranial pressure Symptoms include “three main signs”, i.e. headache, vomiting and optic disc edema. 3.Focal symptoms depend on the location of intracranial tumor. Common focal symptoms include motor and sensory dysfunction, such as weakness, paralysis and numbness of limbs, convulsions or seizures, visual impairment, visual field loss, olfactory impairment, neurological deafness, speech disorder, balance disorder, intellectual decline, psychiatric symptoms, endocrine disorder and developmental abnormalities. They often form different syndromes. Examination 1. Imaging tests include cranial X-ray, radionuclide cerebrography, ventriculography and cerebral poolography, cerebral angiography, etc. These examinations used to be important diagnostic methods for neurological diseases, which not only have the significance of lesion localization, but also have certain qualitative diagnostic value. However, these examinations, except for X-ray, are damaging and should be chosen carefully according to the need. 2.CT examination CT can confirm the diagnosis rate of intracranial tumor up to more than 90%, which is one of the main diagnostic methods for brain tumor. Intracranial tumor and normal brain tissue have considerable difference in histology, and different tissue structures have different CT values and show different densities, thus showing the lesions on CT images. 3.Magnetic resonance imaging MRI can provide clear anatomical background image, especially the head image is not disturbed by posterior cranial fossa artifacts, has sharp brain gray and white matter contrast, and can make coronal, sagittal and axial level tomography, which is more superior than CT. Intravenous injection of a compound of the paramagnetic substance gadolinium (Gd) (Gd-DTPA) results in a significant shortening of the T-1 relaxation time of the tissue and can therefore be used as an enhancer to increase the contrast between the lesion and normal brain tissue and improve the resolution of MRI. It has been generally accepted that MRI should be preferred for the diagnosis of neurological lesions. Diagnosis Any patient with increased intracranial pressure and progressive worsening of neurological symptoms should be considered for the possibility of intracranial occupying lesions. The diagnosis of intracranial tumor can be suggested in some cases by detailed history and neurological examination. In recent years, with the development of neuroimaging technology and functional examination technology, adjuvant examination has become the main means to diagnose intracranial tumor. Treatment 1.Surgery is the most basic and effective treatment for intracranial tumor. All the parts that can be reached by surgery should be completely resected or largely resected without causing significant neurological dysfunction. Surgical treatment of intracranial tumors includes tumor resection, internal decompression, external decompression and shortcut surgery. Due to the development of micro-neurosurgery technology, most of benign intracranial tumors can be completely resected and well protected from neurological function at present. Even for malignant tumors, surgical removal of the tumor plus other treatments can achieve better results. Partial resection of tumor to reduce the volume of tumor or internal and external decompression, cerebrospinal fluid shunt and other palliative surgery can temporarily relieve intracranial hypertension, fight for other treatment time and prolong the survival time of patients. 2.Radiotherapy Various gliomas, pituitary adenomas, germ cell tumors, chordoma, craniopharyngioma and some metastatic carcinomas have different degrees of sensitivity to radiation, and radiation therapy can be given after surgery. Chemotherapy for intracranial tumors includes systemic administration and local administration. Systemic administration includes oral or intravenous injection, local administration includes intrathecal injection, intra-arterial cannulation, super-selective tumor blood supply artery perfusion and intra-tumor cavity administration. The ideal chemotherapeutic drug should be able to pass the blood-brain barrier smoothly, non-toxic to central nervous system, and maintain high concentration in blood and cerebrospinal fluid for a long time. 4.Photodynamic therapy (PDT) Hematoporphyrin derivatives (HPD) treated with acetic acid or sulfuric acid can not only cross the blood-brain barrier, but also be easily absorbed by tumor cells. The accumulation of HPD in tumor cells can be 5-20 times larger than that of normal tissue cells, and it can stay in the cells for 48 h. If the tumor bed is irradiated with argon laser during this period, the tumor cells containing photosensitive substances will lose their vitality or die due to photophysical reaction. 5.Thermal energy treatment Tumor cells are more sensitive to thermal energy than normal cells. When the temperature of tumor area is increased to 42℃～43℃, tumor cells can be killed while normal cells are not affected. Heating can be done by microwave or radiofrequency current, with the temperature controlled at 43℃ and the time for 20-30 minutes. Heat therapy can enhance the effect of radiotherapy, and it seems to be more reasonable to combine with radiotherapy.