Choroid plexus papilloma is a slow-growing benign tumor that originates from the epithelial cells of the choroid plexus in the ventricles of the brain. The incidence of this disease is low, and foreign literature reports that it accounts for 0.4%-0.6% of all intracranial tumors and 1.7%-2.0% of neuroepithelial tumors. The disease can occur at any age, but it is more common in children, mainly before the age of 10, and its occurrence accounts for about 3% of intracranial tumors in children. The literature reports that children under the age of 10 years account for 48% of all choroid plexus papillomas, of which about 20% occur in infants under the age of 1 year. The prevalence of this disease is more in males than females, and the ratio of males to females is 1.6:1. The prevalence of this disease varies with age, but in children it is more often found in the lateral ventricles and in adults it is more often located in the fourth ventricle, and in those with tumors in the lateral ventricles it is more often located in the triangular area, and can also occur in the temporal horn, frontal horn or body. Papilloma of the choroid plexus occurring in the posterior cranial recess can be seen not only in the lateral crypt of the fourth ventricle or inside or outside the fourth ventricle, but also in the cerebellar horn of the pontine brain, where the tumor originated in the lateral crypt of the fourth ventricle or the fourth ventricle and protruded to the cerebellar horn of the pontine brain through the lateral foramen. The latter tumor originates in the lateral sulcus of the fourth ventricle or the fourth ventricle and protrudes into the pontocerebellar horn through the lateral foramen. Tumors occasionally occur on the convex side of the brain due to the ectopic development of embryonic remnants of choroid plexus tissue. Pathology The tumor originates from the ventricular choroid plexus tissue. Therefore, most of them occur in the ventricles of the brain and are generally small in size, pink in color, nodular in growth, and clearly demarcated from the brain tissue surrounding the tumor. The surface of the tumor is small and papillary or granular, which is also called mulberry-shaped. The surface of the tumor is rough and the tissues are easy to fall off, the texture is brittle, cystic changes and hemorrhagic necrosis rarely occur, and small calcified particles can be seen. Clinical manifestations The duration of the disease varies, with an average of about one and a half years. There are two main types of manifestations: increased intracranial pressure and limited neurological damage. (1) Hydrocephalus and increased intracranial pressure Most patients have hydrocephalus, the causes of which include obstructive hydrocephalus due to direct obstruction of cerebrospinal fluid circulation by the location of brain tumor and traffic hydrocephalus due to disorder of cerebrospinal fluid production and absorption. The increased intracranial pressure in infants and children is directly related to the occurrence of hydrocephalus. In infants and children, increased intracranial pressure is manifested by an enlarged head and increased anterior chimney tone, indifference, drowsiness or irritability. In older children and adults, it may manifest as headache, vomiting, optic nerve papillary edema, and even paroxysmal coma. (2) Restricted neurological damage The manifestation of restricted neurological damage varies depending on the location of the tumor. If the tumor is located in the lateral ventricle, half of them have mild contralateral cone bundle sign; if it is located in the posterior part of the third ventricle, it shows difficulty in upward vision of both eyes; if it is located in the posterior cranial sulcus, it shows unstable walking, nystagmus and ataxic movement disorder. Individuals located in the lateral ventricles may present with head masses. A history of spontaneous subarachnoid hemorrhage is seen in this disease. Most of the tumors are located in the ventricles, and some of them are mobile, so some patients show a sudden increase in cephalic epilepsy and relief. This may be due to sudden obstruction of cerebrospinal fluid circulation pathway after tumor movement. CT examination: the tumor is high-density in CT scan and uniformly enhanced in enhanced scan. The borders are clear and irregular, and pathological calcification can be seen. The tumor is mostly unilateral or bilateral, and the triangular area is mostly located in the lateral ventricle, while those located in the posterior cranial recess are mostly accompanied by supratentorial hydrocephalus. Except for choroid plexus papillary carcinoma, tumors are mostly confined to intracerebroventricular region without obvious midline structural displacement. MRI examination: The tumor shows low signal in Tl-weighted image, which is lower than the signal of brain parenchyma but higher than the signal of cerebrospinal report; it shows high signal in T2-weighted image, which is clearly demarcated from cerebrospinal fluid and irregular in outline of swelling, and some of them can be seen as calcification. The tumor has significant contrast enhancement and hydrocephalus. Treatment and prognosis The treatment of choroid plexus papilloma is surgical resection, and total resection should be achieved if possible. For those occurring in the fourth ventricle, a craniotomy should be performed in the posterior cranial recess, and for those protruding to the cerebellar angle of the pontine brain, a lateral postauricular hook incision can be made, and a single bone window in the Shen should be performed. If the tumor is too large, it is not necessary to make a complete resection to prevent damage to the deep structures, and pay attention to block the tumor supplying artery before resection to reduce bleeding during surgery. For those who cannot completely remove the tumor but can relieve hydrocephalus, bypass surgery should be performed. In case of choroid plexus papilloma, postoperative radiation therapy should be given. With the advancement of microscopic neurosurgical techniques, the operative mortality rate can be controlled to less than 1%; and patients with total resection of the tumor can often obtain very satisfactory long-term results. Even the 5-year survival rate of papillary carcinoma of the choroid plexus can reach 50%.