Subependymoma is a slow-growing benign tumor that is rarely licked. It was first identified and described by Scheinker in 1945. Subsequent authors have reported on it and found that some cases of subependymoma have a family history, suggesting that there may be a genetic component to its development. Other authors have suggested that subventricular ventricular meningioma is a type of malformation tumor caused by local abnormalities in the development of the ventricular meninges, which may be caused by proliferation of healthy searching ventricular meninges or subventricular glial cells due to long-term chronic ventriculitis. Disease Overview Ventricular meningioma is a tumor of the central nervous system that arises from the ventricular cells of the ventricles and central canal of the spinal cord or from nests of ventricular meningioma cells in the white matter of the brain. They are more common in men than in women, and are more common in children and young adults. Disease descriptionVentricular meningioma is a tumor of the central nervous system that arises from the ventricular cells of the ventricles and the central canal of the spinal cord or from the nests of white matter ventricular meningeal cells in the brain. They account for 18.2% of gliomas, are more common in men than women, and are more common in children and young adults. Most of the tumors are located in the ventricles of the brain, but a few of the tumor bodies are in the brain tissue. Etiology of the disease Ventricular meningioma is mostly located in the ventricles of the brain, while the main body of a few tumors is located in the brain tissue. Ventricular meningiomas of the posterior cranial recess occur mainly in the parietal, basal, and lateral wall depressions of the fourth ventricle, and most tumors located in the fourth ventricle originate in the medulla oblongata of the ventricular base. Tumor growth may occupy the fourth ventricle and cause obstructive hydrocephalus. Sometimes, tumor may extend through the middle foramen to the occipital pool, and a few may compress or even encircle the medulla oblongata or protrude into the spinal canal and compress the superior cervical medulla. Some tumors originate from the roof of the fourth ventricle and occupy the cerebellar hemisphere or the earthworm, and occasionally tumors occur in the pontocerebellar horn. Supratentorial tumors are mostly found in the lateral ventricles and can originate from all parts of the lateral ventricles, often infiltrating into the brain parenchyma. They are rare in the third ventricle, and those located anteriorly may extend through the interventricular foramen into both ventricles. Supratentorial ventricular meningiomas are thought to originate from the ventricular epithelium of the lateral ventricles or the third ventricle, and tumors can be either completely intraventricular or partially intraventricular and partially extraventricular. However, tumors may also occur anywhere within the cerebral hemispheres and be located entirely outside the ventricles. Tumors originating from the ventricular meningeal cell crest may be the result of malformations that form when the neural tube is folded internally, and such tumors tend to occur in the frontal, temporal, parietal, and third ventricles. Diagnostic tests 1.Diagnosis: According to clinical manifestations and auxiliary examinations, diagnosis can be made in general. 2.Laboratory examination: The majority of patients have increased lumbar puncture pressure, which is especially prominent when the subscreen tumor is combined with hydrocephalus. About half of the patients have increased cerebrospinal fluid protein and about 1/5 of the patients have increased cerebrospinal fluid cell count. Since tumor cells are often shed in the cerebrospinal fluid, it is necessary to pay attention to the differentiation between cerebrospinal fluid and white blood cells when microscopic examination. 3.Other auxiliary examinations: cranial CT and MRI have diagnostic value for ventricular meningioma. The tumor appears as a slightly dense shadow with clear boundary on CT scan, in which low density is interspersed. The tumor often shows high-density calcification. Calcification and cystic changes are more common in supratentorial tumors than in infratentorial tumors. Some of the supratentorial tumors are located in the brain parenchyma, and the surrounding brain tissue shows a mild to moderate edema zone. On MRI, T1-weighted is low and isosignal shadow, and proton-weighted and T2-weighted is high signal. The tumor shows moderate to significant enhancement shadow after injection of enhancing agent, and some of them are irregularly enhanced. The tumor shows low signal in T1W and high signal in T2W and proton-weighted images. The signal within the tumor is heterogeneous and there may be necrotic cystic lesions. Subventricular ventricular meningioma appears on CT as a tumor with equal or low density and clear borders located in the ventricles. On MRI, the tumor shows low signal in T1W and high signal in T2W with proton weighting. About half of the tumors have heterogeneous signal, caused by calcification or cystic degeneration. Some tumors may have inhomogeneous enhancement after injection of enhancer. Surgical total resection of the tumor is the treatment of choice for ventricular meningioma. Intraventricular ventricular meningioma can be treated with extraventricular drainage to lower intracranial pressure. The surgical mortality rate for supratentorial ventricular meningiomas has been reduced to 0%-2%, while the surgical mortality rate for subatrial tumors ranges from 0%-13%. For patients who fail to undergo total tumor resection, postoperative radiation therapy should be administered. Although there is no uniform understanding of postoperative radiation therapy for ventricular meningiomas, most authors recommend radiation therapy at a dose of 50-55 Gy. Prophylactic irradiation of the cerebral spinal cord is not necessary for ventricular meningioma because the majority of recurrences are in situ in the tumor bed. While postoperative chemotherapy has no significant effect in adult patients, it is still an important adjuvant therapy for patients with recurrence or young children who are not candidates for radiotherapy. Commonly used chemotherapy drugs include carmustine, lomustine, etoposide (etoposide), cyclophosphamide and cisplatin. Chemotherapy for infants and children under 3 years of age can be started 2-4 weeks after surgery, with a 4-week break to start the next course of treatment, which can prolong patient survival and thus allow patients to receive radiotherapy after 3 years of age. Surgery is still the mainstay of treatment for interstitial ventricular meningioma, and postoperative radiotherapy is necessary, preferably early and at a higher dose of 55-60 Gy. Prophylactic cerebrospinal radiotherapy is also required. Chemotherapy is one of the adjuvant therapies to control tumor growth in the short term. Surgery is the main measure for radical treatment of subventricular ventricular meningioma. With the application of micro-neurosurgical techniques, the surgical mortality rate is almost zero. As subventricular ventricular meningioma grows expansively and has clear borders, most of them can be completely resected. For those who have deep tumor growth site and it is difficult to achieve total tumor resection, subtotal resection can also obtain good treatment effect. Radiotherapy is generally not routinely used. However, radiotherapy is recommended for patients with pleomorphic nuclei or mixed ventricular meningioma – subventricular ventricular meningioma. Ventricular meningioma has a high recurrence rate, and the prognosis for posterior cranial recess tumors in children is poor, with almost all cases recurring at various times after surgery. Ventricular meningioma is prone to intradural dissemination and implantation. One study counted 436 cases of ventricular meningioma in all age groups, with 11% having intradural implantation. Intradural implantation is more common in submural ventricular meningiomas than in supratentorial ones. The incidence of ventriculoblastoma metastases is significantly higher than that of ventricular meningioma. Extracranial metastases from intracranial ventricular meningiomas are rare and have only been reported in isolated cases. Clinical reports of disseminated implants often underestimate the true rate at which this occurs because spinal cord imaging is not routinely done in the vast majority of cases. Analysis of clinical data on patients with spinal implant metastases from posterior cranial sulcus ventricular meningioma showed a 6% incidence of disseminated implants, while 21 series reported a combined incidence of 15%. The incidence of subarachnoid implant dissemination varied according to the site of the tumor, with supratentorial ventricular meningiomas showing an 8% rate of intradural implant dissemination compared with a 15% incidence of implant dissemination in posterior cranial sulcus ventricular meningiomas. There are also significant differences in metastatic dissemination by tumor pathologic grade, with approximately 20% of high-grade ventricular meningiomas presenting with intravertebral spreading implants compared with 9% of low-grade tumors. In general, ventricular meningiomas of high malignant grade are more likely to present with intralesional implantation than lower grade tumors, and in addition, submural ventricular meningiomas have a higher rate of disseminated metastases than supratentorial tumors. The likelihood of soft meningeal metastases directly affects the determination of the extent of radiation therapy, and although cerebrospinal fluid dissemination detected at autopsy is relatively common, neuroimaging performed prior to radiation therapy has shown that the rate of tumor dissemination is low, except in young children. The Children’s Tumor Investigation Group reported that 43 pediatric ventricular meningiomas had neither positive myelographic findings nor positive vertebral MRI findings prior to radiation therapy, and the vast majority of patients with soft meningeal metastases had a concurrent recurrence at the primary site.