Central neuroblastoma is a rare benign tumor of the nervous system. In recent years, there is an increasing trend of reports, and its treatment is mainly based on total surgical resection. There is a great controversy whether to adjuvantly treat tumors that remain after surgery or recur after surgery with radiation therapy. There are few reports on the efficacy of radiation therapy for central neuroblastoma in China. In this paper, we report the results of 6 cases admitted during the period from June 2003 to June 2005 and discuss them with literature review. Data and methods From June 2003 to June 2005, a total of 6 cases with residual intra-lateral ventricular neuroblastoma after surgery were admitted, and the diagnosis was confirmed by pathology. Among them, 4 cases were male and 2 cases were female, with a mean age of 35.2 years. The lesions were all located in the anterior part of the lateral ventricle and invaded the pellucid septum. 5 cases were mainly in one ventricle but invaded the pellucid septum and the contralateral ventricle, and 1 case was located in one ventricle. There was no or mild cerebral edema but no involvement of brain parenchyma, and there were two cases each with cystic degeneration and a small amount of old hemorrhage. 2 M 34 Major resection External radiotherapy 56 36 Tumor shrinkage Return to work* 3 M 34 Partial resection External radiotherapy 56 24 Tumor shrinkage Return to work 4 F 42 Partial resection External radiotherapy 55 28 Tumor shrinkage Return to work 5 M 42 Partial resection External radiotherapy 58 30 Tumor shrinkage Return to work 6 M 35 Endoscopic biopsy Gamma knife 15 24 Tumor shrinkage Return to work with mild memory loss Outcome Among the five patients who received external radiation therapy, the follow-up period ranged from 24 to 36 months (mean 30 months), with one case of lesion disappearance and four cases of lesion shrinkage (Figure 1). The lesion disappearance occurred 24 months after treatment, but in this case, radiation necrosis of normal brain tissue in the radiation treatment area occurred 6 months after the end of radiation treatment (Figure 2), and the lesion reduction occurred 12 to 18 months after radiation treatment. One patient treated with gamma knife was pathologically confirmed by ventricular endoscopic biopsy before treatment, and the lesion had shrunk significantly by 18 months of follow-up (Figure 3). After surgical resection, two patients developed incomplete hemiparesis, two developed mental and memory loss, all of which gradually improved during the follow-up period, three returned to work (one with mild memory loss), two were self-care and one was semi-self-care. Except for one patient who developed radionecrosis, no other important complications were found during the follow-up period. Discussion Biological behavior of CNS cells: This disease is clinically rare, Hassoun et al [1] reported the first case in 1982 and described the diagnostic criteria for this disease: typical lateral ventricular sites, especially in the MONRO’s foramen area; histologically well differentiated, with mature differentiation of neuronal cells; and a benign clinical course with slow growth. About 210 cases were reported worldwide in 1997, and a review of the literature up to 2001 reported about 300 cases. Features include: a predilection for middle-aged and young adults; lateral ventricular tumors originating from the neural structures of the ventricles; and light microscopic similarity to oligodendrogliomas and ventricular meningiomas. Therefore, it is easy to misdiagnose the disease as oligodendroglioma or ventricular meningioma by light microscopy alone in the early stage of recognition. Most authors consider the disease to be a benign lesion, but there are several reports of extraventricular or rapidly growing atypical neuroblastic fine tumors of the central nervous system. For example, Mark et al [2] in 1994 reported two cases of malignant neuroblastoma with tumors located in the frontal brain parenchyma and rapid growth of the tumor the patient died quickly. yasargil et al [3] reported that malignant neuroblastoma is characterized by endothelial proliferation, high mitotic rate and local necrosis. The above reports are based on histological features only and do not take into account the clinical course, which does not conclusively suggest that the malignant histological features are indeed accompanied by a worsening clinical course during clinical follow-up. Therefore, histological manifestations characterized by local necrosis, endothelial proliferation and mitosis are not important influencing factors when predicting the outcome of CNS neuroblastoma. As the lesions are mostly located in the anterior part of the lateral ventricles and sometimes enter the third ventricle through the interventricular foramen or invade the contralateral ventricle via the pellucid septum, they tend to cause hydrocephalus. The local recurrence rate after subtotal resection is approximately 0-33% [4-7]. However, the role of adjuvant radiation therapy in the long-term outcome has not been established, so it is controversial whether adjuvant radiation therapy should be performed in patients who have not undergone total resection or who have recurred postoperatively. By 1993, 41 cases were reported in the literature with details of treatment and outcome [8], of which 23 received external radiation therapy, resulting in two postoperative deaths and one death from meningitis at 14 months after radiation therapy, with overall survival rates of 94.9%, 91.7% and 91.7% at 1, 2 and 5 years, respectively. The overall survival rates at 1,2,5 years were 94.9%, 91.7% and 91.7%, respectively, indicating that CNS neuroblastoma is highly sensitive to radiation therapy. Kim 1997 [4] reported 15 cases of CNS neuroblastoma, two of the seven cases with total sarco-optic resection received external radiation therapy, two of the five patients who did not receive radiation therapy had tumor recurrence 8 and 21 months after surgery, respectively, while the two patients who received external radiation therapy had no recurrence; five of the eight cases with subtotal resection received external radiation therapy, and at the subsequent follow-up of 27 to 113 months The time of tumor shrinkage ranged from 6 months to 2 years after radiotherapy, and the other 3 patients who did not receive external radiotherapy showed no change in their tumors during the follow-up period. Therefore, it is concluded that the biological behavior of central neuroblastoma is benign and radiation therapy can control tumor growth, but the clinical course of residual tumors after subtotal resection is very benign due to the delayed complications that radiation therapy itself can cause, so careful consideration should be given to whether to apply radiation therapy to postoperative residual tumors. Zentner et al [7], on the other hand, opposed radiation therapy after surgery on the grounds that central neuroblastoma is a benign tumor and long-term survival can be achieved in patients who did not receive radiation therapy.Yasargil et al [3] considered that external radiation therapy should be applied to tumors with histologically malignant manifestations; Sgouros et al [6] agreed that external radiation therapy should be applied to postoperative residual tumors, but it is also necessary to Sgouros et al [6] agreed with the use of external radiation therapy for postoperative residual tumors, but at the same time there is a need for close follow-up to determine the effectiveness of this treatment. In this regard, Rades et al [9] in 2005 statistically analyzed the results of various treatments for well-differentiated CNS neuroblastoma reported in the literature, and a total of 301 patients were enrolled in the complete resection group (108); complete resection plus external radiation therapy group (27); partial resection group (81) and partial resection plus external radiation therapy group (85), and the results showed that the tumor control rate and The results showed that the tumor control rate and survival rate in the total resection group were significantly higher than those in the partial resection group; radiation therapy significantly improved the tumor control rate in the partial resection and total resection groups, but did not improve their survival rates; in the partial resection plus external radiation therapy group, there was no significant difference in the tumor control rate and survival rate for radiation doses greater than or less than 54 Gy. It was concluded that the administration of external radiation therapy should be decided according to the patient’s condition, and the side effects of re-surgical resection and radiation therapy should also be considered. As for the radiation dose, Rades [10] summarized the results of radiation therapy for central neuroblastoma reported in the literature since 1982, with the inclusion criteria being incomplete surgical resection, postoperative radiation therapy, and complete data and follow-up for more than one year. All patients were divided into two groups: 42 patients in group A (40.0-53.6 Gy) and 47 patients in group B (54.0-62.2 Gy), and the 5 and 10-year local tumor control rates were 69% in group A and 98% in group B, 65% and 89% in groups A and B (p = 0.0066). Survival rates at 5 and 10 years in both groups were 88% in group A and 98% in group B (p = 0.1). The data suggest that radiation doses equal to or greater than 54 Gy improve local control of incompletely resected tumors and result in better survival rates. A pooled analysis of all literature data for atypical (those with atypical histology or high proliferative activity) concluded that for incompletely resected patients, radiation therapy improved the local control rate (p