Medulloblastoma is a common malignant tumor in children, second only to astrocytoma, and is the most common tumor of the posterior cranial recess in children. Medulloblastoma accounts for 6.2-18.2% of pediatric intracranial tumors, with an annual incidence of 2.19-6.6 per million children. It is more common in male children, with peak incidence at 6-9 years of age. The vast majority of medulloblastomas occur randomly, and only 10 cases of familial medulloblastoma have been reported worldwide as of 2002. 1. What are the manifestations of medulloblastoma? Medulloblastoma is highly malignant, so the history is short, averaging 4-5 months. High cranial pressure is common in children. 95% of children have vomiting, followed by cerebellar symptoms, such as trunk ataxia and nystagmus. Other manifestations include diplopia, facial palsy, forced head position, cone bundle sign, choking on food and water, and cranial enlargement in younger children. 2.Where does medulloblastoma grow? Medulloblastoma grows mainly in the cerebellar earth and the fourth ventricle, so it is often combined with hydrocephalus, and can also grow in the cerebellar hemispheres and the pontocerebellar horn. Medulloblastoma can metastasize to the whole brain and spinal cord with cerebrospinal fluid. 3.How is medulloblastoma treated? Surgery is preferred for medulloblastoma to minimize the tumor volume and open up the cerebrospinal fluid circulation. The tumor is sensitive to radiotherapy, and smaller tumors can disappear with radiotherapy alone, so radiotherapy should be given as early as possible after surgery. In fact, surgery plus radiotherapy is the main treatment that must be done for medulloblastoma and has the greatest impact on prognosis. Medulloblastoma is more sensitive to chemotherapy, but the effect of chemotherapy alone is general, so chemotherapy should be carried out on the basis of surgery and radiotherapy as much as possible. 4.What is the outcome of surgery for medulloblastoma? The most ideal surgical result is complete or near-total resection of the tumor, no aggravation or even improvement of preoperative symptoms, no new symptoms, and disappearance of hydrocephalus. The next best outcome is complete or near-total resection of the tumor, but new cranial nerve symptoms or ataxia and hydrocephalus requiring additional surgical shunt. Once again, there is obvious residual tumor, postoperative cerebellar muteness, and hematoma in the operative cavity. 5.Factors affecting the treatment of medulloblastoma? The extent of intraoperative resection is an important factor affecting the prognosis. In the selection of postoperative treatment plan, it is conventional to divide the children into two groups, high risk and low risk, according to the age of the child and the extent of surgical resection and the presence of metastasis, and to take corresponding treatment measures for different groups. The prognosis of medulloblastoma In recent years, with the development of treatment, the 5-year survival rate of medulloblastoma has reached 50-60%, and the 10-year survival rate is 40-50%. Local recurrence of medulloblastoma is rare, mainly because tumor cells spread and metastasize in the brain and spinal subarachnoid space with cerebrospinal fluid circulation. Local recurrence alone can be considered for reoperation, but once metastasis has occurred, few patients survive beyond 2 years. In addition, a small number of patients present with a recurrence of hydrocephalus and require shunting. Patients who have already undergone shunts may develop shunt blockage.