Volume 38 · Issue 09 · 2022

To investigate the diagnostic significance of hyperintense fluid-attenuated inversion-recovery (FLAIR) rim (hyperFLAIRrim) sign for isocitrate dehydrogenase (IDH) mutant 1p/19q non-codeleted (IDHmut-Noncodel) astrocytoma.

A total of 585 lower-grade glioma (LGG) (World Health Organization grade 2-3) patients who received craniotomy at the Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University from December 2013 to December 2020 were included in this study and their clinical data were retrospectively analyzed. The sensitivity and specificity of T2-FLAIR mismatch and hyperFLAIRrim sign were evaluated. Besides, calcification information was assessed for subgroup analysis. The application value was further determined combined with the calcification information.

In 585 qualified patients, 71.3% (186/261)of IDHmut-Noncodel astrocytomas were hyperFLAIRrim positive, and hyperFLAIRrim sign was absent in oligodendrogliomas and IDH wild-type LGGs. The sensitivity for T2-FLAIR mismatch and hyperFLAIRrim sign was 0.52 and 0.71, respectively, and the specificity was 1.00 for both. For all calcific tumors, 85.8% (115/134) were oligodendroglioma. And the sensitivity of T2-FLAIR mismatch and hyperFLAIRrim sign in non-calcific tumors was 0.54 and 0.74, respectively, and the specificity of 1.00 for both.

The hyperFLAIRrim sign seems more sensitive for IDHmut-Noncodel astrocytoma without compromised specificity. Combining calcification could further improve the diagnosis sensitivity.

To explore the clinical and pathological features of multinodular and vacuolating neuronal tumors (MVNT).

A retrospective analysis was conducted on the clinical data of 4 patients with MVNT diagnosed by the Neuropathology Center of Beijing Institute of Neurosurgery, Beijing Tiantan Hospital Affiliated to Capital Medical University from January 2019 to June 2022. Four patients underwent tumor resection, and postoperative re-examination of head MRI was performed to determine the extent of tumor resection. All patients were followed up and inquired about their symptom improvement, radiotherapy, chemotherapy and tumor recurrence. HE staining, immunohistochemical staining and gene sequencing were performed on tumor tissue samples.

The median age of the 4 patients was 38.5 years old (24-42 years old) who were mostly males (3/4). The symptoms were mainly headache and dizziness, with or without epileptic seizure. The median course of disease was 2 years (3 months to 10 years). Four patients′ lesions were all located in the temporal lobe and hippocampus. The largest diameter of the tumor was 2.5-4.0 cm. The tumors mainly involved the deep cerebral cortex showing characteristic "beadlike" or "nodular" abnormal signals. The scan showed no (2/4) or mild (2/4) uneven enhancement. The tumors of all 4 patients were completely resected, and none of them received radiotherapy or chemotherapy after surgery. The median follow-up time of the 4 patients was 12 months (3-43 months). At the last follow-up, the preoperative symptoms of all 4 patients were significantly improved and MRI showed no signs of recurrence. Macroscopically, multiple discrete or coalesced gray nodules involved deep cortex, gray matter-white matter junction, and subcortical white matter. HE staining showed that MVNT consisted of small-to-medium-sized neuronal cells arranged in nodules, with obvious vacuoles in the background stroma and in the cytoplasm of tumor cells. The results of immunohistochemical staining showed that myelin basic protein (MBP) in the nodule was weakly positive compared with the normal cortex, giving the nodular lesions a " wormlike" appearance. Microtubule association protein 2 (MAP2) was positive expression in varying degrees, and synaptophysin (Syn) was granularly and weakly positive. Neurofilament (NF) and neuro-specific nuclear protein (NeuN) were negative. Glial fibrillary acidic protein (GFAP) showed " spider-like" expression of reactive astrocytes in the background. CD34 expression was negative in tumor cells, but ramified in neural elements of the adjacent dysplastic cerebral cortex. The next-generation sequencing results of 4 patients showed that there was 1 case of FGFR4 P400 frameshift mutation and BRAF A34 indel, and 1 case of NOTCH1 L188V mutation. Three of 4 patients underwent pyrosequencing which showed no methylation of O⁶-methylguanine DNA methyltransferase (MGMT).

MVNT is more common in adults and mainly involves temporal lobe and hippocampus. It shows characteristic " beaded" or " nodular" abnormal signals in MRI and unique multinodular and vacuolar pathological features. MVNT can be totally resected by surgery and has good prognosis.

To explore the guiding value of collateral vein classification in parasagittal meningiomas for intraoperative vein management.

The clinical data of 68 patients with parasagittal meningioma who underwent surgical resection from March 2017 to July 2020 at the Department of Neurosurgery, Tangdu Hospital, Air Force Medical University were retrospectively analyzed. The peritumoral collateral veins of all patients were classified according to the results of preoperative magnetic resonance venography (MRV) examination and the drainage of collateral veins around the tumor during the operation, and the management of the veins during the operation was guided according to the classification results. The extent of tumor resection was assessed according to the Simpson grading system. Postoperative CT and MRI were routinely performed to determine the extent of tumor resection and the occurrence of venous infarction. The patients underwent clinical follow-up after surgery, and the neurological outcome of the patients was assessed by the Glasgow Outcome Scale (GOS).

The peritumoral collateral veins in 68 cases were divided into 4 types: (1) No anastomosis (12 cases): veins surrounded the tumor. (2) End-to-end anastomosis (17 cases): The anterior and posterior veins of the occluded sinus communicated with each other. (3) Superficial vein anastomosis (25 cases): Occluded sinus peritumoral collateral veins mainly drained into superficial veins. (4) Deep vein anastomosis (14 cases): Occluded sinus peritumoral collateral veins mainly drained into deep veins. Intraoperative accidental or purposeful injury to peritumoral collateral veins occurred in 12 cases, and complications related to secondary vein injury occurred in 4 cases(5.9%). According to the Simpson classification, 18 cases were grade Ⅰ, 24 cases were grade Ⅱ, 15 cases were grade Ⅲ, and 11 cases were grade Ⅳ. All 68 patients were followed up for 6 months after operation. At the last follow-up, the GOS score was as follows: 66 cases were grade Ⅴ, 1 case was grade Ⅳ, and 1 case was grade Ⅲ.

Peritumoral collateral vein classification has reference value for the management of veins in resection of parasagittal meningiomas. Intraoperative management of peritumoral collateral veins can be guided by the classification, which helps reduce or avoid complications caused by venous infarction secondary to venous injury.

To evaluate the optimal monitoring methodology and application value of lower cranial nerve motor evoked potentials (MEPs) in skull base and brainstem tumors surgery.

The clinical data of 51 patients with skull base and brainstem tumors surgically treated at the Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University from December 2018 to March 2019 were retrospectively analyzed. All patients underwent bilateral transcranial electrical stimulation for monitoring of the MEPs of the lower cranial nerves, which were recorded in the intraoral and extraoral muscle groups innervated by the lower cranial nerves. According to the intraoperative real-time threshold changes, an increase in the difference in the real-time/baseline thresholds between the surgical and non-surgical sides by >20% was used as an early warning indicator. The patients′ swallowing function was evaluated by the Mann Assessment of Swallowing Ability (MASA) before and 1 month after the operation, and the postoperative-preoperative MASA grade increase by ≥1 grade was defined as the deterioration of swallowing function. Spearman′s rank correlation test was used to analyze the correlation between the changes in surgical and non-surgical endpoints/baseline thresholds and postoperative swallowing function changes in different muscle groups. The receiver operating characteristic curve was drawn and the area under the curve (AUC) was calculated to compare the prognostic values of the surgical and non-surgical endpoint/baseline threshold changes in the intraoral, extraoral, and intraoral-extraoral muscle groups for the patients′ swallowing function at 1 month after surgery.

MEPs were successfully induced in 49 (96.1%) out of 51 patients. There was no significant difference in the baseline threshold, end point threshold, end point/baseline threshold change or technical success rate of MEPs in the intraoral and extraoral muscles innervated by the lower cranial nerves (all P>0.05). In terms of monitoring related complications, the risk of hemorrhage and hematoma in the posterior pharyngeal muscle was significantly higher than that in the cricothyroid muscle [17.6% (18/102) vs. 5.9% (6/102), P=0.009]. Combined monitoring of intraoral-extraoral muscle group MEPs showed a higher correlation between the end point/baseline threshold change on surgical/non-surgical sides and worsening of postoperative swallowing function than monitoring of merely intraoral or extraoral muscle groups (r values: 0.74, 0.62, and 0.63 respectively, P<0.01). The predictive value of combined monitoring of intraoral and extraoral muscle group MEPs was better than that of monitoring of merely intraoral muscle group or extraoral muscle group (AUC: 0.94, 0.87, and 0.87, P<0.05). The sensitivity of combined monitoring of intraoral-extraoral MEPs was 89.3%, and the specificity was 95.7%; the sensitivity of monitoring of intraoral MEPs was 73.3%, and the specificity was 81.0%; the sensitivity of monitoring of extraoral MEPs was 80.6%, The specificity was 95.0%.

Combined monitoring of intraoral and extraoral muscle groups is the optimal method for intraoperative monitoring of lower cranial nerve MEPs in skull base and brainstem tumors, which can safely and effectively evaluate the structural and functional integrity of swallowing-related nerves and predict postoperative swallowing function.

To investigate the clinical characteristics, treatment methods and prognosis of atypical choroid plexus papilloma (aCPP) in children.

The clinical data of 10 children with aCPP admitted to the Department of Neurosurgery, Beijing Children′s Hospital, Capital Medical University from January 2014 to November 2021 were retrospectively analyzed. Among them, 7 cases of tumors involved only one side of the lateral ventricle and its trigone region, and tumor resection was performed through unilateral trigone region approach. For the other 2 cases involved the third ventricle and bilateral lateral ventricles, and 1 case involved the temporal, parietal, and occipital lobes, tumor resection via interfornical approach of corpus callosum plus subdural or extraventricular drainage were performed, and subdural-peritoneal or ventriculoperitoneal shunt was performed later. Outpatient or telephone follow-up was performed at 1, 3, and 6 months after surgery, 1 year after surgery, and annually thereafter. Postoperative radiotherapy and chemotherapy, secondary surgical treatment, new-onset neurological dysfunction, etc. were followed up. Imaging follow-up was performed for tumor spread and metastasis. No enhancement in the intracranial tumor cavity on postoperative brain MRI enhanced scan indicated total tumor resection.

The median age at presentation of the 10 patients was 1 year (3 months to 11 years and 2 months), and 8 of them were younger than 2 years. All patients lesions were supratentorial and achieved total tumor resection, and postoperative symptoms improved. The pathological grades of 10 children were all World Health Organization (WHO) grade Ⅱ; immunohistochemical staining showed that all of them were positive for vimentin, weakly positive for cytokeratin (CK) and S-100, and the Ki-67 index was 6% to 30%. The median postoperative follow-up of the 10 patients was 51 months (6 months to 8 years). Nine cases did not receive chemotherapy after operation, and one case received related chemotherapy for acute lymphoblastic leukemia 2 years after operation. By the last follow-up, none of the 3 children who underwent shunt surgery in the later stage had shunt-related complications, and their muscle strength was further improved. Of the remaining 7 cases, one with preoperative brain trauma died while the symptoms of the other 6 cases were relieved. The contrast-enhanced MRI results of the 9 surviving children showed that the intracranial tumor cavity was not enhanced, and none of them had cerebrospinal fluid dissemination, metastasis or recurrence.

The onset of aCPP is often at less than 2 years old, and the aCPP in children mostly originates from the choroid plexus in the supratentorial ventricle. After craniotomy, the tumor can be completely removed, and the overall prognosis is good.

To explore the clinical characteristics and prognosis of intracranial chondrosarcoma.

A total of 12 cases of intracranial chondrosarcoma treated in the Department of Neurosurgery of the First Affiliated Hospital of Zhengzhou University from April 2011 to September 2019 (accounting for 0.12% of patients with intracranial tumors admitted during the same period) were enrolled into this study and their data were retrospectively analyzed. The tumor was located in the cavernous sinus and sellar region in 5 cases, middle cranial fossa in 4 cases, petroclival region in 1 case, temporo-occipital region in 1 case, and parieto-occipital region in 1 case. Only 5 cases were diagnosed as chondrosarcoma preoperatively. All patients underwent tumor resection, and among them 5 underwent postoperative radiotherapy and 1 case received postoperative chemotherapy. Follow-up was performed by telephone and outpatient visits. Kaplan-Meier method was used to analyze the progression-free survival and overall survival of the patients. The clinical characteristics and prognosis of intracranial chondrosarcoma were summarized.

Of the 12 patients, total resection were achieved in 7 cases, near-total resection in 2, and partial resection in 3. Pathological results revealed 6 cases of chondrosarcoma gradeⅠ, 3 cases of chondrosarcoma grade Ⅱ, 3 cases of mesenchymal chondrosarcoma. The 2-year progression-free survival and overall survival ratios were 7/12 and 11/12 respectively. During the follow-up period of 13-123 months, 5 patients had tumor recurrence and 2 patients died of recurrence. Tumor recurred in all 3 patients with mesenchymal chondrosarcoma.

Intracranial chondrosarcoma is a rare intracranial tumor with high misdiagnosis rate and mostly located at the skull base. Surgical resection and adjuvant radiotherapy are mostly used as the treatment, and the prognosis is relatively good.

To explore the risk factors and treatment strategies of intraoperative cerebrospinal fluid (CSF) leakage during transnasosphenoidal neuroendoscopic surgery for pituitary adenomas.

A retrospective analysis was conducted on the clinical data of 676 patients with pituitary adenomas who were registered in the National Brain Tumor Registry Platform of China (https: //www.nbtrc.cn) and treated with transnasosphenoidal endoscopic surgery at the Department of Neurosurgery, the First Affiliated Hospital of Zhengzhou University from January 2019 to July 2020. According to the presence or absence of intraoperative CSF leakage and its severity degree, the patients were divided into grades 0-3 CSF leakage, and different skull base reconstruction techniques were adopted. CSF leakage grades 1 to 3 were defined as intraoperative CSF leakage group (117 cases), and grade 0 was defined as no intraoperative CSF leakage group (559 cases). The clinical characteristics of the two groups of patients were compared, and multivariate logistic regression analysis was used to determine the influencing factors of intraoperative CSF leakage.

Skull base reconstruction was completed in all 676 patients. Intraoperative CSF leakage occurred in 117 cases (17.3%) which included 56 cases of CSF leakage grade 1, 38 cases of grade 2, and 23 cases of grade 3. Postoperative CSF leakage occurred in 5 cases, none of the patients showed the symptoms of CSF leakage when they were discharged. The follow-up time of 676 patients was 8.1±2.4 months (6-12 months), and there were no complications such as intracranial infection or CSF leakage during the follow-up period. Compared with the group without intraoperative CSF leakage, the intraoperative CSF leakage group had higher proportions of patients with secondary surgery, abnormal preoperative visual acuity, Knosp grade 3 and 4, Hardy-Wilson grade C, D and E, and stiff tumor, and the difference was statistically significant (all P<0.05). The results of multivariate logistic regression analysis showed that secondary surgery (OR=3.05, 95%CI: 1.70-5.44, P<0.001), Hardy-Wilson classification [C grade (OR=7.16, 95%CI: 4.02-13.10, P<0.001), grades D and E (OR=11.41, 95%CI: 5.68-23.55, P<0.001)], tumor texture (OR=2.13, 95%CI: 1.21-3.70, P=0.008) were all influencing factors of intraoperative CSF leakage during transnasosphenoidal neuroendoscopic resection of pituitary adenomas.

Patients with secondary surgery, higher Hardy-Wilson grades, and stiff tumors have a higher risk of intraoperative CSF leakage during transnasosphenoidal neuroendoscopic surgery for pituitary adenomas. Skull base reconstruction techniques based on the grading of intraoperative CSF leakage are relatively safe and effective.

To investigate the clinical features, neurosurgical strategies and therapeutic effects of Langerhans cell histiocytosis in orbital apical region.

The clinical data of 15 patients with orbital apical Langerhans cell histiocytosis admitted to the Department of Neurosurgery, Beijing Tongren Hospital, Capital Medical University from January 2014 to January 2021 were retrospectively analyzed. All patients underwent surgical treatment. In 10 cases, the tumor was mainly located outside and above the optic nerve, so orbital apex mass resection was performed by the pterion approach. Neuroendoscopic transnaso-orbital apex mass resection was performed in 5 cases with tumors mainly located in the lower part of optic nerve and protruding into sphenoid sinus. Orbital CT, enhanced MRI and ophthalmic examination were performed to evaluate the surgical efficacy. Regular imaging examinations were performed during follow-up to observe whether the lesions recurred.

Among the 15 patients, the main clinical manifestations were visual impairment in 8 cases, headache in 5 cases, exophthalmos in 4 cases, and ocular movement disorder in 2 cases. All tumors were resected and confirmed by pathological examination. The visual acuity was improved in 7 cases and unchanged in 1 case. The symptoms of 9 patients with headache and exophthalmos were significantly relieved. In 2 patients with ocular movement disorder, 1 case returned to normal after operation, and 1 case had no change. There were no postoperative complications such as cerebrospinal fluid leakage or intracranial infection. Among them, 4 patients were transferred to the Department of Oncology for follow-up treatment such as radiotherapy and chemotherapy. All 15 patients were followed up for 6 months to 5 years, and there was no long-term cerebrospinal fluid leakage, orbital infection, ethmoid sinus, sphenoid sinusitis or other complications during the follow-up. Up to the last follow-up, there was no local recurrence or new lesions in distant sites.

The main clinical manifestations of Langerhans histiocytosis in orbital apical region include decreased vision, headache and exophthalmia. The surgical approach is determined according to the relationship between tumor and optic nerve location. Postoperative total resection rate seems high and complications are few.

To explore the localizing and lateralizing values of interictal and ictal scalp electroencephalogram (EEG) patterns in patients with epilepsy caused by focal cortical dysplasia (FCD).

We retrospectively selected consecutive 171 patients who had undergone resective epilepsy operations at the Medical Alliance of Epilepsy Center of Beijing Tiantan-Fengtai Hospital between January 2015 and December 2019. All patients underwent preoperative EEG and MRI, and semiology analyses were performed. Thereafter, all patients underwent resective epilepsy surgery, and their outcomes were classified according to the Engel classification scheme. According to the postoperative outcomes, the correct localization and lateralization rates of interictal and ictal scalp EEG patterns for the epileptogenic zone were analyzed and further compared with MRI and semiology results.

All surgeries were uneventful for 171 cases. Histopathology of brain tissues confirmed FCD type Ⅰ in 30 cases (17.6%), FCD type Ⅱ in 90 cases (52.6%), and FCD type Ⅲ in 51 cases (29.8%). The correct localization rate based on the pattern of repetitive discharges during the interictal scalp EEG was 70.7% (53/75). The correct localization rate based on the pattern of the coexistence of a single discharge (slow wave or sharp wave/spike) and any characteristic FCD waveforms in the same location was 71.9% (46/64) and 75.0% (12/16), respectively, which were both higher than that based on the pattern of ictal low-voltage fast activity onset (68.0%, 34/50). The correct localization rates of scalp EEG patterns, except for single sharp wave/spike, were higher than those of semiology and MRI. In the MRI-positive subgroup, the correct localization rate of MRI was similar to that of scalp EEG. The correct lateralization rate of ictal scalp EEG was higher than that of interictal scalp EEG. The correct lateralization rate of semiology and MRI remained lower than that of scalp EEG. The median follow-up time of 171 patients was 48 months (30-62 months), and all patients had the outcome of Engel grade Ⅰ at the last follow-up.

During noninvasive preoperative evaluation of patients with FCD-related refractory epilepsy, the localizing and lateralizing values of scalp EEG are high. Analysis of preoperative scalp EEG can improve the accuracy of intraoperative resection of the epileptogenic zone.

To investigate the predictive value of intraoperative transcranial electrical stimulation motor evoked potential (TES-MEP) monitoring for the patient′s muscle strength post craniocerebral surgery.

A retrospective analysis was conducted on 59 patients with craniocerebral surgery who underwent intraoperative TES-MEP monitoring from January 2019 to December 2020 in the Department of Neurosurgery, Changzhou Second People′s Hospital Affiliated to Nanjing Medical University. Changes of intraoperative TES-MEP amplitude and muscle strength before and 1 month after surgery were documented. According to the changes of muscle strength, the patients were divided into muscle strength decreased group and muscle strength non-decreased group. Univariate analysis and binary logistic regression analysis were used to explore the influencing factors of muscle strength changes at 1 month after craniocerebral surgery.

The results of univariate analysis showed that the proportion of intraoperative TES-MEP amplitudes with an irreversible decrease of >50% in the muscle strength decreased group (5/8) at 1 month after surgery was higher than that of the postoperative muscle strength non-decreased group (1/50) (P<0.001). The preoperative Glasgow coma score in the group with decreased muscle strength at 1 month after operation was lower than that in the group without postoperative muscle strength decrease (P<0.001). Binary logistic regression analysis revealed that the intraoperative TES-MEP amplitude decrease was an independent influencing factor for muscle strength changes 1 month post surgery (OR: 51.77, 95% CI: 4.07-658.96, P=0.002). The irreversible reduction greater than 50% in the TES-MEP amplitude predicted a decrease in muscle strength 1 month after surgery. The results of receiver operating characteristic curve analysis showed that the area under the curve for diagnosing the changes in muscle strength at 1 month after surgery was 0.803, the sensitivity was 0.625, and the specificity was 0.980. The positive predictive value was 83.3% and the negative predictive value was 94.3%.

The change of 50% in intraoperative TES-MEP amplitude as an alarm criterion has a good predictive value for postoperative limb function changes in neurosurgical patients. The irreversible decrease greater than 50% in the TES-MEP amplitude can predict a lower muscle strength 1 month after surgery than before surgery.

To analyze the correlation of posttraumatic acute diffuse brain swelling(PADBS)and subarachnoid hemorrhage (SAH) and to preliminarily explore its mechanisms.

A retrospective analysis of 48 patients with cerebral contusion and laceration admitted to the Department of Neurosurgery of the Affiliated Hospital of Southwest Medical University from March 2017 to April 2020 was performed. According to the head CT at the time of admission, the patients were divided into the PADBS group (26 cases) and the non-swelling group (22 cases). The difference in the incidence of SAH between the two groups was analyzed. All patients underwent CT perfusion imaging (CTP), and the differences in CTP-related parameters were compared between the two groups. Three patients with SAH and decompressive craniectomy were selected from each of the two groups of patients. The discarded brain tissue removed during the operation was used for the human genome-wide expression profiling microarrays, and the differences in gene expression between the two groups were analyzed.

In this series, 76.9% (20/26) of patients in the PADBS group had SAH, which was higher than 40.9% (9/22) in the non-swelling group. The difference was statistically significant (P<0.05). CTP showed that cerebral blood volume and cerebral blood flow were decreased, and the mean transit time of cerebral blood flow was prolonged in the PADBS group (all P<0.05). Gene microarray analysis showed that compared with the non-swollen group, the expression of inflammation, immune, stress response-related genes in the brain tissue of the PADBS group was significantly down-regulated, including hypoxia-inducible factor 1α (HIF-1α), hexokinase 2 (HK2) and lactate dehydrogenase (LDHA) in the glycolytic pathway(all P<0.05).

PADBS may be associated with traumatic SAH, and the mechanism may be related to retarded hypoxic stress response.

To summarize the epidemiological characteristics of primary neurological tumors in children by a survey of 44 hospitals in Beijing.

Data of 4 951 children with primary CNS tumors diagnosed based on the pathological examination (age <18 years old) collected from the Beijing Municipal Health Commission Information Center from January 2015 to December 2019 were retrospectively analyzed. The distribution of children′s age, gender, World Health Organization (WHO) tumor grade, anatomical location and pathological type of tumor was statistically analyzed.

Among 4 951 children with a median age of 8 years old(Q₁, Q₃: 4, 12) males accounted for 58.43% (2 893 cases); intracranial tumors accounted for 91.21% (4 516 cases), spinal cord tumors accounted for 8.80% (435 cases); low-grade tumors(WHO tumor grade Ⅰ, Ⅱ) accounted for 69.38 % (3 435 cases). Compared with spinal cord tumors, children with intracranial tumors had a younger age, a higher proportion of males, and a lower proportion of low-grade tumors, and the differences were statistically significant (all P<0.05). Among children with intracranial tumors, supraten-torial tumors accounted for 56.53% (2 553 cases) and infratentorial tumors accounted for 43.47% (1 963 cases). Compared with infratentorial tumors, children with supratentorial tumors were older and had a higher proportion of low-grade tumors (all P<0.01). After age stratification, there were more males than females in children of different ages, but the difference was not statistically significant (P>0.05). The proportion of low-grade tumors was higher than that of high-grade tumors, and the proportion of intracranial tumors located in the supratentorial was higher than that of the subtentorial tumors (both P<0.01). Among the 4 951 children, there were 17 first-level pathological classifications, of which the top 5 were diffuse astrocytoma and oligodendroglioma (17.55%, 869 cases), embryonal tumor (15.75%, 780 cases), sellar tumors (12.77%, 632 cases), neuronal and mixed neuronal glial tumors (12.52%, 620 cases), other astrocytic tumors (9.84%, 487 cases). The fewest was other type of glioma (0.02%, 1 case). Among the 4 516 cases of intracranial tumors, the top 5 types with the highest proportion of pathological secondary classification were medulloblastoma (14.11%, 637 cases), craniopharyngioma (13.99%, 632 cases), and pilocytic star cell tumor (9.96%, 450 cases), diffuse astrocytoma (9.74%, 440 cases), and anaplastic ependymoma (3.90%, 176 cases). All were the highest in the age group of 3-<9 years old [44.09% (194/440)-56.82% (100/176)], 15~<18 years old accounted for the lowest [3.41% (6/176)-10.00% (44/440)], and the proportion of males was higher than that of females (1.11-1.98 times). Among the 435 spinal cord tumors, the top 5 types with the highest proportion were lipoma (25.75%, 112 cases), perineurioma (17.47%, 76 cases), teratoma (12.87%, 56 cases), CNS neuroblastoma (7.59%, 33 cases) and ependymoma (5.52%, 24 cases). Between 2015 and 2019, there was an overall upward trend in the number of children with CNS tumors.

In general, pediatric CNS tumors show the characteristics that the proportion of males is higher than that of females, and there are more low-grade tumors than high-grade tumors. The common types of intracranial tumors and spinal cord tumors are different, but the distributions of age, gender and pathological grade are generally similar.