1.What is the incidence rate of intracranial tumors in children? What are the common brain tumors in children? The incidence of intracranial tumors in children accounts for the second highest incidence of childhood tumors. The common brain tumors in children are glioma, medulloblastoma, craniopharyngioma, ventricular meningioma and germ cell tumor. 2.What are the main clinical features of intracranial tumors in children? Intracranial tumors in children can be divided into two categories: general symptoms (caused by increased intracranial pressure) and limited localization signs (caused by local compression and destruction of brain tissues by tumors), and the clinical features mainly include: vomiting, headache, optic papilledema, visual acuity loss, visual field defects, cranial enlargement, positive pot-breaking sound (McCewen’s sign), diplopia, cervical resistance, forced head position, seizures, altered consciousness, unsteady walking, ataxic movement disorder, and germ cell tumors. The diagnosis of intracranial tumor in children should be based on the following factors 3.Diagnosis of intracranial tumor in children is more difficult than that in adults, what are the physiological characteristics of children? The diagnosis of intracranial tumor in children is more difficult than that in adults because of the following factors: (1) Children cannot or will not express their symptoms correctly, so the medical history is not accurate and often relies on the family’s recollection and speculation to describe, which increases the difficulty of doctors’ judgment; (2) Children are not easy to cooperate in neurological examination, and the positive signs are often not easily detected because of crying; (3) The cranial suture or fontanelle is not closed, and the increase of intracranial pressure caused by brain tumor is often compensated by the enlargement of the skull, which makes the symptoms appear. (4) Many symptoms are atypical and often confused with other physical diseases; (5) Pediatric neurosurgery is still not popular in China, and there are very few hospitals with independent specialized wards for pediatric neurosurgery. 4.What are the common clinical symptoms and signs of children with craniopharyngioma? (1) High intracranial pressure: The main reason for the increase of intracranial pressure is that the tumor grows upward and invades the third ventricle and obstructs the interventricular foramen, and in a few cases, the tumor compression may also lead to the occlusion of the aqueduct, thus causing more obstructive hydrocephalus. The occupying effect of huge tumor itself is also one of the reasons for the increase of intracranial pressure. In children, increased intracranial pressure is manifested by headache, vomiting, enlarged skull, separation of cranial sutures and broken pot sounds on head percussion; in infants, it is manifested by bulging fontanelle and angry scalp veins. (2) Endocrine function hypoplasia: endocrine function disorder is mainly due to tumor invasion or compression of pituitary gland and hypothalamus, which is a syndrome of endocrine function disorder. The clinical manifestations of hypothalamic damage include uremia, fat metabolism disorder, drowsiness and thermoregulation disorder. The clinical manifestations of pituitary impairment include easy weakness and lethargy, little movement, poor appetite, pale skin, low basal metabolism, non-development of sexual organs or non-appearance of secondary sexual characteristics. Insufficient secretion of various pituitary hormones can lead to Lorain’s dwarfism, which is characterized by emaciation, lethargy, hypermobility, pale skin, wrinkled face resembling an old man, underdeveloped teeth and bones, and infantile sexual organs without secondary sexual characteristics. (3) Visual field impairment: There are two reasons for this: firstly, the tumor is located in the suprasellar area, which compresses the optic nerve, optic cross and even optic bundle, causing primary atrophy of the optic nerve. The second is that the tumor obstructing the interventricular foramen can cause the intracranial pressure to increase, resulting in optic papillar edema. 5.What are the symptoms of endocrine dysfunction in children with craniopharyngioma? Endocrine dysfunction is mainly due to the syndrome of endocrine dysfunction caused by tumor invasion or compression of pituitary gland and hypothalamus. The clinical manifestations of hypothalamic damage include uremia, fat metabolism disorder, lethargy, and thermoregulation disorder. The clinical manifestations of pituitary impairment include easy weakness and lethargy, little movement, poor appetite, pale skin, low basal metabolism, non-development of sexual organs or non-appearance of secondary sexual characteristics. Inadequate secretion of various pituitary hormones may lead to Lorain’s dwarfism, which is characterized by emaciation, lethargy, hypermobility, pale skin, wrinkled face, and lack of development of teeth and bones, as well as infantile sexual organs without secondary sexual characteristics.