Indirect revascularization for pediatric moyamoya disease

OBJECTIVE

Indirect revascularization is a common and effective treatment for pediatric moyamoya disease. However, in several cases postoperative angiogenesis is not sufficient. It is not fully understood which factors are involved in the development of postoperative collateral circulation. In this study, the authors aimed to elucidate the factors related to postoperative angiogenesis in indirect revascularization.

METHODS

Among the patients who underwent indirect revascularization for moyamoya disease from January 2015 to December 2022, those whose angiogenesis was evaluated using angiography were included. Age, onset symptoms, comorbidities, preoperative imaging findings, surgical details, perioperative complications, postoperative imaging findings, and modified Rankin Scale (mRS) score at the last outpatient visit were retrospectively examined.

RESULTS

Ninety cases (53 patients; 37 bilateral, 16 unilateral) were included. Sixty-eight cases (75.6%) were symptomatic. The mean age at surgery was 7.9 years, and the mean postoperative follow-up duration was 48.5 months. Frontotemporal encephalo-duro-arterio-synangiosis (EDAS) was performed in all cases, and simultaneous frontal encephalo-galeo-synangiosis (EGS) was performed in 34 cases. Postoperative angiography revealed insufficient angiogenesis in 14 of 90 cases (15.6%) after frontotemporal EDAS and in 8 of 34 cases (23.5%) after frontal EGS. A high degree of ivy sign depicted on preoperative MRI was found to be significantly correlated with good angiogenesis after both surgical procedures (p = 0.00030 for EDAS and p = 0.0039 for frontal EGS). In addition, an advanced preoperative Suzuki stage was significantly correlated with good postoperative angiogenesis after EDAS (p = 0.00040). Good angiogenesis was significantly correlated with postoperative improvement of the ivy sign in both procedures (p = 0.0005 in EDAS and p = 0.030 in frontal EGS) as well as correlated with a better mRS score at long-term follow-up after EDAS (p = 0.018).

CONCLUSIONS

Preoperative ivy sign and Suzuki classification are related to the degree of angiogenesis achieved after indirect revascularization for pediatric moyamoya disease.

Two Cases of Children With Black Hairy Tongue and Tooth Discoloration Caused by Antibacterial Agents

Black hairy tongue (BHT) is a lesion in which the filiform papillae of the tongue are significantly extended by hyperkeratosis, thereby giving the tongue a hairy appearance. Here, we report two rare cases of children with BHT and tooth discoloration caused by antimicrobial agents. Case 1: A four-year-old female patient received intravenous linezolid after spinal surgery, and BHT developed on day eight of treatment. Subsequently, the patient developed teeth discoloration. Linezolid was continually administered for 50 days, and BHT and teeth discoloration improved 10 days after the end of linezolid treatment. Case 2: A two-year-old male patient with a brain abscess received intravenous meropenem and vancomycin. On the fourth day of treatment, BHT developed, and teeth discoloration was subsequently observed. Antibiotic therapy was continued for 82 days, and BHT and tooth discoloration improved 20 days after the treatment was discontinued.

Alteration of major venous drainage routes in a patient with achondroplasia after ventriculoperitoneal shunt placement

Achondroplasia is the most common form of dwarfism, caused by a mutation in fibroblast growth factor receptor 3 gene, leading to multiple pathological conditions. Herein, we present a case of an infant with achondroplasia associated with hydrocephalus and severe foramen magnum stenosis. Computed tomography (CT) venography showed prominent suboccipital emissary veins comprising major venous drainage routes and hypoplastic transverse sinuses, which increased the risk of foramen magnum decompression. The infant was initially treated with ventriculo-peritoneal (VP) shunt. After 8 months, CT venography showed regression of suboccipital emissary veins and more prominent transverse sinuses. Subsequently, foramen magnum decompression was safely performed without sacrificing major venous drainage routes.

Atretic cephalocele associated with sinus pericranii: a single-center analysis

PURPOSE

The purpose of this report is to investigate the association of atretic cephalocele (AC) with sinus pericranii (SP) in order to improve the management of AC.

METHODS

Pediatric patients with AC who underwent repair surgeries were retrospectively analyzed. Anomalies including SP were evaluated using computed tomography angiography and venography (CTA/V) as well as magnetic resonance imaging.

RESULTS

Fourteen patients were identified, comprising of 5 males and 9 females. The AC was located interparietally in 8 cases and occipitally in 6 cases. Seven cases (50%) were found to be associated with SP, all of which did not involve major intracranial venous circulation. Five out of 8 parietal ACs (63%) were accompanied by SP, while 2 out of 6 occipital ACs (33%) exhibited SP. All of the SP associated with AC only contributed to a small portion of the venous outflow, and the repair surgeries were successfully performed without excessive bleeding.

CONCLUSION

More than half of the ACs were associated with SP, with a higher prevalence in the parietal region compared to the occipital region. For the appropriate management of AC, preoperative investigation of SP using CT venography is considered important.

Cranial distraction osteogenesis for craniosynostosis associated with osteopetrosis: A case report

Background

Osteopetrosis is a rare disease characterized by systemic osteosclerosis and hematopoietic disturbances. Childhood-onset cases are often accompanied by hydrocephalus and craniosynostosis; however, there have been no established treatments. We performed cranial distraction in a child with osteopetrosis who presented with craniosynostosis and intracranial hypertension.

Case Description

The patient was a 4-year-1-month-old boy. His pregnancy and birth were normal, but at 4 months of age, he was diagnosed with osteopetrosis based on generalized osteosclerosis and family history. A computed tomography scan of the head revealed early sagittal suture fusion and ventricular enlargement. A ventriculoperitoneal shunt was placed for intracranial hypertension; however, slit ventricle syndrome ensued and pansynostosis developed. To improve uncontrolled high intracranial pressure, cranial distraction was performed for intracranial volume expansion. No perioperative hemorrhagic or infectious complications were observed. After the start of distraction, the intracranial pressure gradually decreased, and clinical findings such as disturbance of consciousness and bradycardia disappeared. Bone regeneration in the defect site was good, and the extension device was removed 6 months after the operation.

Conclusion

For osteopetrosis with poorly controlled intracranial hypertension, cranial distraction was considered to be an effective treatment.

Pineal/germ cell tumors and pineal parenchymal tumors

INTRODUCTION

Pineal region tumors (PRTs) are tumors arising from the pineal gland and the paraspinal structures. These tumors are rare and heterogeneous that account for 2.8-10.1% and 0.6-3.2% of tumors in children and in all ages, respectively. Almost all types and subtypes of CNS tumors may be diagnosed in this region. These tumors come from cells of the pineal gland (pinealocytes and neuroglial cells), ectopic primordial germ cells (PGC), and cells from adjacent structures. Hence, PRTs are consisted of pineal parenchyma tumors (PPTs), germ cell tumors (GCTs), neuroepithelial tumors (NETs), other miscellaneous types of tumors, cystic tumors (epidermoid, dermoid), and pineal cyst in addition. The symptoms of PRTs correlate to the increased intracranial cranial pressure due to obstructive hydrocephalus and dorsal midbrain compression. The diagnostic imaging studies are mainly MRI of brain (with and without gadolinium) along with a sagittal view of whole spine. Serum and/or CSF AFP/β-HCG helps to identify GCTs. The treatment of PRTs is consisted of the selection of surgical biopsy/resection, handling of hydrocephalus, neoadjuvant and/or adjuvant therapy according to age, tumor location, histopathological/molecular classification, grading of tumors, staging, and threshold value of markers (for GCTs) in addition.

METHODS

In this article, we review the following focus points: 1. Background of pineal region tumors. 2. Pineal GCTs and evolution of management. 3. Molecular study for GCTs and pineal parenchymal tumors. 4. Review of surgical approaches to the pineal region. 5. Contribution of endoscopy. 6. Adjuvant therapy (chemotherapy, radiotherapy, and combination). 7.

FUTURE DIRECTION

RESULTS

In all ages, the leading three types of PRTs in western countries were PPTs (22.7-34.8%), GCTs (27.3-34.4%), and NETs (17.2-28%). In children and young adults, the leading PRTs were invariably in the order of GCTs (40-80.5%), PPTs (7.6-21.6%), NETs (2.4-37.5%). Surgical biopsy/resection of PRTs is important for precision diagnosis and therapy. Safe resection with acceptable low mortality and morbidity was achieved after 1970s because of the advancement of surgical approaches, CSF shunt and valve system, microscopic and endoscopic surgery. Following histopathological diagnosis and classification of types and subtypes of PRTs, in PPTs, through molecular profiling, four molecular groups of pineoblastoma (PB) and their oncogenic driver were identified. Hence, molecular stratified precision therapy can be achieved.

CONCLUSION

Modern endoscopic and microsurgical approaches help to achieve precise histopathological diagnosis and molecular classification of different types and subtypes of pineal region tumors for risk-stratified optimal, effective, and protective therapy. In the future, molecular analysis of biospecimen (CSF and blood) along with AI radiomics on tumor imaging integrating clinical and bioinformation may help for personalized and risk-stratified management of patients with pineal region tumors.

Second-look surgery for pineal region tumors

PURPOSE

Surgical resection of pineal region tumors is challenging because of close proximity to the vein of Galen draining system and the quadrigeminal plate. Surgical resection usually is performed through the narrow corridor by piecemeal resection and en bloc resection is difficult in cases of large tumors. Moreover, in cases of hypervascular tumors, surgical resection through the narrow corridor could entail massive intraoperative bleeding. The effectiveness of neoadjuvant chemotherapy and second-look surgery for pineal region tumors for maximal safe resection was evaluated.

METHODS

Retrospective institutional review of pediatric patients with pineal region tumors who underwent second look surgery after neoadjuvant chemotherapy was performed.

RESULTS

Nine patients underwent surgical resection after neoadjuvant chemotherapy over the period of September 2017 to February 2022. The mean age was 7.7 years (ranged from 1.4 to 15.3 years). Three patients underwent partial resection via open craniotomy, and 6 underwent endoscopic biopsy as an initial surgery. The histopathological diagnoses were germ cell tumors in 5 patients (yolk sac tumors in 2, germinoma in 2, choriocarcinoma in 1), /rhabdoid tumor (AT/RT) in 2, medulloblastoma in 1, and high-grade glioneuronal tumor in 1. After several courses of chemotherapy, the second-look surgery was performed. The tumor volume was reduced in 8 patients (89%) after chemotherapy except for 1 case of growing teratoma syndrome. The tumor was extended laterally to the ambient cistern in 2 patients, and posteriorly to the tentorial surface of the cerebellum in 3 patients. The lesion was approached through occipital transtentorial approach in 8 patients and infratentorial supracerebellar approach in 1. Intraoperatively, the high vascularity of the tumor was not observed in all cases. Gross total resection (8 patients, 89%) or near total resection (1, 11%) was achieved in all cases. No complications were observed postoperatively in all cases. Eight patients subsequently underwent additional chemo-radiation therapy according to the initial diagnosis. All patients are alive with no evidence of recurrence with a mean follow-up of 33 months.

CONCLUSIONS

Neoadjuvant chemotherapy and second-look surgery for pediatric pineal region tumors was considered to be effective in reducing the tumor volume and vascularity, which facilitates the safe maximal tumor resection.

Prevention of retethering in untethering surgery of a tight filum terminale

OBJECTIVE

Untethering surgery for a tight filum terminale is a common treatment with considerable efficacy and safety. On the other hand, retethering has been reported to occur. One of the major mechanisms of retethering is adherence of the cut end of the sectioned filum to the midline dorsal dural surface. To prevent retethering, the authors sectioned a filum terminale at the rostral level to the dural incision to keep the distance between the cut end of the sectioned filum and the dural incision and investigated whether this procedure decreased the occurrence of retethering.

METHODS

Among the patients who underwent untethering surgery for a tight filum terminale between 2012 and 2016, patients followed up more than 5 years were included in the study. Symptoms, comorbid malformations, preoperative imaging, surgical details, perioperative complications, and long-term outcomes were reviewed retrospectively.

RESULTS

Retrospective data for a total of 342 cases were included. The median age at surgery was 11 months (range 3-156 months). Preoperative MRI revealed 254 patients (74.3%) had a low-set conus. There were 142 patients (41.5%) with filar lipoma and 42 patients (12.3%) with terminal cyst. Syringomyelia was found in 29 patients (8.5%). In total, 246 patients (71.9%) were symptomatic and 96 patients (28.1%) were asymptomatic. There were no perioperative complications that required surgical intervention or prolonged hospitalization. The mean postoperative follow-up was 88 months (range 60-127 months). There were 4 patients (1.2%) with retethering who presented with bladder and bowel dysfunction. The mean time from initial untethering to retethering was 54 months (range 36-80 months). All 4 patients underwent untethering surgery, and preoperative symptoms resolved in 3 patients.

CONCLUSIONS

The retethering rate after untethering surgery for a tight filum terminale in our series was lower than those in previously reported studies. Sectioning the filum terminale at the rostral level to the dural incision was considered an effective way to prevent retethering.

Spinal Subarachnoid Hematoma After Cardiac Angiography in an Infant: A Case Report

Spinal subarachnoid hematoma may result in sequelae such as bilateral lower extremity paralysis and vesicorectal disturbances. Although spinal subarachnoid hematoma is rare in infants, early intervention has been suggested to improve neurological prognosis. Therefore, clinicians are encouraged to make early diagnosis and surgical intervention. A 22-month-old boy was prescribed aspirin for a congenital heart disease. A routine cardiac angiography was performed under general anesthesia. Fever and oliguria developed on the next day, followed by flaccid paralysis of the lower limbs four days later. Five days later, he was diagnosed with spinal subarachnoid hematoma and associated spinal cord shock. Even after emergent posterior spinal decompression, hematoma removal, and rehabilitation, the patient remained with bladder rectal disturbance and flaccid paralysis of both lower limbs. Diagnosis and treatment of this case were delayed mainly because of his difficulty to complain of back pain and paralysis. The neurogenic bladder was one of the first neurological symptoms in our case, so it may be important to consider spinal cord involvement in infants with bladder compromise. Risk factors for spinal subarachnoid hematoma in infants are largely unknown. The patient had undergone a cardiac angiography the day before the onset of the symptoms, which may be related to subarachnoid hematoma. However, similar reports are scarce, with only one case of spinal subarachnoid hematoma reported in an adult following cardiac catheter ablation. Accumulation of evidence regarding risk factors for subarachnoid hematoma in infants is warranted.

Evaluation of radiation dose reduction in head CT using the half-dose method

PURPOSE

The present study introduced the half-dose method (HDM), which halves the radiation dose for conventional head computed tomography (CT), for postoperative hydrocephalus and follow-up for craniosynostosis at a children's hospital. This study aimed to evaluate the contribution of selective head CT scanning optimization towards the overall reduction of radiation exposure.

MATERIALS AND METHODS

We retrospectively assessed 1227 and 1352 head CT examinations acquired before and after the introduction of the HDM, respectively, in children aged 0-15 years. The radiation exposure was evaluated using the CT dose index volume (CTDI-vol), dose-length product (DLP), rate of HDM introduction, and effect of reducing in-hospital radiation dose before and after the introduction of the HDM. For an objective evaluation of the image quality, head CT scans acquired with HDM and full-dose method (FDM) were randomly selected, and the image noise standard deviation (SD) was measured for each scan. In addition, some HDM images were randomly selected and independently reviewed by two radiologists.

RESULTS

The HDM was introduced in 27.9% of all head CTs. The mean CTDI-vol of all head CTs was 21.5 ± 6.9 mGy after the introduction, a 14.9% reduction. The mean DLP was 418.4 ± 152.9 mGy.cm after the introduction, a 17.2% reduction. Compared to the FDM images, the noise SD of the HDM ones worsened by almost 0.9; however, none of the images were difficult or impossible to evaluate.

CONCLUSION

The HDM yielded diagnostically acceptable images. In addition, a change in protocol for only two diseases successfully reduced the patients' overall radiation exposure by approximately 15%. Introducing and optimizing the HDM for frequently performed target diseases will be useful in reducing the exposure dose for the hospital's patient population.

BOT-3 GENOME-WIDE ASSOCIATION STUDY OF INTRACRANIAL GERM CELL TUMORS: A COMMON DELETION ATBAK1 ATTENUATES THE ENHANCER ACTIVITY AND CONFERS RISK FOR THE BRAIN TUMORS IN CHILDREN ADOLESCENTS AND YOUNG ADULTS

Intracranial germ cell tumors (IGCTs) are rare brain tumors that mainly occur in children, adolescents and young adults with a particularly high incidence in East Asian populations. The biological basis of these tumors is still largely unknown. We conduct a genome-wide association study (GWAS) of 133 patients with IGCTs and 762 controls of Japanese ancestry by using Infinium Asian Screening Array and other molecular biology methods. A common 4-bp deletion polymorphism in an enhancer adjacent to BAK1 is significantly associated with the disease risk (rs3831846; P = 2.4 × 10−9, odds ratio = 2.46 [95% CI: 1.83-3.31], minor allele frequency = 0.43). Rs3831846 is in strong linkage disequilibrium with a testicular GCTs susceptibility variant rs210138. Expression quantitative trait locus (eQTL) analysis using the GTEx dataset reveals that the risk allele of rs3831846 has a down-regulating effect on BAK1 expression in a wide range of tissues. Further in-vitro reporter assays reveal rs3831846 to be a functional variant attenuating the enhancer activity. BAK1 is a pro-apoptotic member of the BCL-2 family, thus our results suggested that the risk allele may contribute to IGCTs predisposition through down-regulating BAK1 expression. Risk alleles of testicular GCTs derived from the European GWAS show significant positive correlations in the effect sizes with the Japanese IGCTs GWAS (P = 1.3 × 10-4, Spearman’s ρ = 0.48). Of the 57 loci, 11 exhibit significant association with IGCTs and these loci were implicated in a broad range of biological pathways, including KIT/KITLG signaling, apoptosis regulation, and telomerase activity. The risk allele frequency of rs3831846 is higher in east Asia than Europe (0.49 vs. 0.20), which may provide a partial explanation for the ethnic difference in incidence. Nevertheless, our results suggest the shared genetic susceptibility of GCTs beyond ethnicity and primary sites.

Longstanding overt ventriculomegaly diagnosed in adolescents, not adults: a pediatric case report

BACKGROUND

Longstanding overt ventriculomegaly in adults (LOVA) is a new form of progressive hydrocephalus characterized by onset in early childhood and gradual progression into adulthood. Patients with LOVA are usually asymptomatic in childhood. The diagnosis of LOVA in adolescence has not been reported.

CASE REPORT

A patient with macrocephaly and mild ventriculomegaly from infancy developed headache exacerbation and cognitive dysfunction at the age of 11 years. Brain magnetic resonance imaging showed mild tri-ventriculomegaly with no radiological aggravation compared to imaging at the age of 8 years. No papilledema was observed. Drainage of 15 ml of spinal fluid via a lumbar puncture relieved the headache and cognitive dysfunction. Based on repeated improvements in cognitive function and headaches after spinal fluid drainage, we diagnosed the patient with LOVA with symptom onset in early adolescence. A ventriculoperitoneal shunt was placed, and the headaches disappeared completely. The full-scale intellectual quotient, verbal comprehension, and working memory improved significantly.

CONCLUSIONS

LOVA may manifest as early as adolescence. The clinical presentation, age, clinical, radiological features, and management vary, and a spinal tap exam is useful for diagnosing LOVA, even in children. The spinal tap exam may be indicated in children with longstanding ventriculomegaly and deteriorating neurological symptoms to diagnose this "treatable intellectual disability."

[Pediatric Posterior Fossa Tumors]

Posterior fossa tumors tend to entail obstructive hydrocephalus, and urges initiating prompt treatment. Prevalent pathologies include medulloblastoma, ependymoma, pilocytic astrocytoma, and atypical teratoid/rhabdoid tumor(AT/RT). In most cases, maximal safe resection is related to better prognosis. In some cases of ependymoma and AT/RT with high vascularity, second-look surgery with neoadjuvant chemotherapy is effective. The treatment strategy should be tailored according to each tumor.

A neonatal purely prepontine arachnoid cyst: a case report and review of the literature

Purely prepontine arachnoid cysts not extending into the suprasellar region in neonates are rare. Herein, we report a purely prepontine arachnoid cyst in a neonate which caused central apnea and was successfully treated with microscopic cyst fenestration and C1 laminectomy.

Endoscopic third ventriculostomy and cerebrospinal fluid shunting for pure communicating hydrocephalus in children

PURPOSE

Recent reports regarding endoscopic third ventriculostomy (ETV) for pediatric hydrocephalus revealed that ETV could avoid cerebrospinal fluid (CSF) shunting in certain types of hydrocephalus. However, the effectiveness of ETV for "pure" communicating hydrocephalus that has no obstruction through CSF pathway is still unknown. In this study, we report clinical outcome of ETV and CSF shunting for communicating hydrocephalus and discuss the efficacy of ETV for pure communicating hydrocephalus.

METHODS

Children less than 15 years old who underwent ETV or CSF shunting for communicating hydrocephalus were retrospectively reviewed. The absence of obstruction through CSF circulation was confirmed by CT cisternography or cine-contrast image in MRI.

RESULTS

Sixty-three patients (45 CSF shunting and 18 ETV) were included. The mean follow-up period was 6.1 years. The success rate was 60% in CSF shunting and 67% in ETV at the last visit (p = 0.867). Normal development was observed in 24 patients (53%) in CSF shunting and 12 patients (67%) in ETV (p = 0.334). There was a significant difference in the mean time to failure (CSF shunting: 51.1 months, ETV 3.6 months, p = 0.004). The factor that affected success rate in ETV was the age at surgery (success 21.6 months, failure 4.4 months, p = 0.024) and ETV success score (success 66.7, failure 50.0, p = 0.047).

CONCLUSION

Clinical outcomes of ETV were not inferior to those of CSF shunting in patients with communicating hydrocephalus. Further studies is required to elucidate to establish the consensus of ETV as a treatment option for communicating hydrocephalus.

[Pediatric Glioma]

Pediatric gliomas include various types of glioma broadly categorized as low- or hi-grade based on histopathological features. Clinically significant types include cerebellar astrocytomas, optic pathway / hypothalamic pilocytic astrocytomas, and brainstem gliomas. Neurosurgical roles vary for different kinds of pediatric gliomas. Since these representative tumors remain rare, the patients should be directed toward facilities with experienced neurosurgeons. Radiotherapy and chemotherapy are very important as either adjuvant or primary treatment modalities. Recent advancements in molecular biology have revealed unique genetic aberrations in different types of pediatric gliomas. The RAS/MAPK pathway anomalies, including BRAF-KIAA1549 fusion and BRAF V600E mutation, are present in most low-grade gliomas. BRAF/MEK-inhibitors have yielded promising clinical study results. Diffuse midline gliomas, including diffuse intrinsic pontine gliomas, often harbor H3 mutations such as H3K27M. Agents that target these molecular aberrations are unavailable. Because gliomas in infants are sub-categorized by their genetic abnormalities, novel agents targeting ALK, ROS1, or NTRK fusions are promising treatments.

Initial symptoms and diagnostic delay in children with brain tumors at a single institution in Japan

Background

A prolonged interval between onset of symptoms and diagnosis of childhood brain tumor is associated with worse neurological outcomes. The objectives of this study are to determine factors contributing to diagnostic delay and to find an interventional focus for further reduction in the interval between symptom onset and diagnosis in Japan.

Methods

We retrospectively analyzed 154 patients younger than 18 years with newly diagnosed brain tumors who visited our institution from January 2002 to March 2013.

Results

The median age at diagnosis was 6.2 years and the median total diagnostic interval (TDI) was 30 days. Patients with low-grade tumors and cerebral midline tumor location had significantly long TDI. Durations between the first medical consultation and diagnosis (diagnostic interval, DI) were exceedingly longer for patients with visual, hearing, or smelling abnormalities as the first symptom (median, 303 days). TDI and DI of patients who visited ophthalmologists or otolaryngologist for the first medical consultation were significantly longer. Among these patients, longer DI was associated with worse visual outcome.

Conclusion

Raising awareness of brain tumor diagnosis among ophthalmologists and otolaryngologists may reduce diagnostic delay and may improve the neurological impairment of children with brain tumors in Japan.

ATRT-11. PREVALENCE OF GERMLINE VARIANTS IN SMARCB1 INCLUDING SOMATIC MOSAICISM IN AT/RT AND OTHER RHABDOID TUMORS

BACKGROUND

Genetic hallmark of atypical teratoid/rhabdoid tumor (AT/RT) is loss-of-function variants or deletions in SMARCB1 gene on 22q11.2 chromosome, which is common to extracranial malignant rhabdoid tumors (MRT). Previous studies demonstrated that approximately one-thirds of AT/RT and extracranial MRT patients harbored germline SMARCB1 variants as the rhabdoid tumor predisposing syndrome. We studied herein intensive analysis of the SMARCB1 gene in AT/RT and extracranial MRT patients focusing on prevalence of germline genetic variants. PROCEDURE: In total, 16 patients were included. Both tumor-derived DNA and germline DNA were obtained from all patients. First, screening for SMARCB1 alterations in the tumor specimens was done by direct sequencing, ddPCR and SNP array analysis. Then, analysis of germline DNA samples focusing on the genomic abnormalities detected in the paired tumors in each case was performed.

RESULTS

In eight of 16 cases (50%), genomic alterations observed in the tumor-derived DNA were also detected in the germline DNA. It is worth noting that three patients had germline mosaicism. Two of three patients had mosaic deletion, including SMARCB1 region, and the average copy number of the deleted region in the SMARCB1 gene in the germline was 1.60 and 1.76. For another patient, the fraction of SMARCB1 variants in normal cells was as low as 1.7%.

CONCLUSIONS

Approximately half the MRT cases in this study had SMARCB1 germline alterations. Considering the presence of low-frequency mosaicisms which conventional methods might overlook, inherited germline variants in predisposition genes are more important than previously assumed for the pathogenesis of pediatric cancers.

RARE-16. SEVEN CASES OF RETINOBLASTOMA WITH CNS INVOLVEMENTS

Treatment strategy for trilateral retinoblastoma (TRb: very rare RB with brain tumor) or retinoblastoma with central nervous system (CNS) involvement is not established yet. We retrospectively reviewed our seven cases of these rare almost fatal tumors. Their ages at diagnosis are 0y3m-1y10m (median 1y3m) (Male 4, Female 3). Only one had RB family history. Their affected eyes were bilateral 3, unilateral 3 and no 1. Their CNS involvements were suprasellar tumor 4, pineal tumor 1 and cerebrospinal fluid (CSF) cytology positive 2. Three of the suprasellar tumor patients had spinal metastasis. Four of the seven patients were TRb and one were genetically classified suprasellar retinoblastoma. All of them were treated with chemotherapy and four received high-dose chemotherapy. Three brain tumors of four TRb almost disappeared with chemotherapy. Two of them also received radiotherapy but relapsed. Although one radiation-free long-term TRb survivor developed secondary osteosarcoma, he got remission again and live 5 more years. One CSF positive Rb patient with chiasm invasion died of disease 11 months later. The other patient had no chiasm invasion nor CSF involvement at diagnosis, but his CSF cytology turned to positive after his second cycle of chemotherapy. He got remission with radiotherapy and high-dose chemotherapy, and alive without disease for 4 years. 2-year RFS and 2-year OS of all patients were 40% and 60%. Although our TRb patients responded to chemotherapy, it was difficult to avoid radiotherapy except one. Data accumulation is necessary for better treatment of these cancer-predisposed patients.

ETMR-11. A CASE OF PRIMARY DIFFUSE LEPTOMENINGEAL PRIMITIVE NEUROECTODERMAL TUMOR

BACKGROUND

Primary diffuse leptomeningeal primitive neuroectodermal tumor (PDL PNET) is a rare embryonal brain tumor which arises primarily in the meninges without an intraparenchymal mass. Few previous reports of this condition exist, and the clinical outcomes are poor. We herein report a case of a child with PDL PNET and present a cursory review of the literature. CASE: A 3-year-old female patient was seen at a local clinic due to vomiting, headaches, and seizures. As a head MRI revealed hydrocephalus but no mass, acute encephalopathy was initially diagnosed. She received steroid pulse therapy, but the symptoms progressed to hallucination and lethargy. Another MRI at the 1-month follow-up revealed diffuse leptomeningeal enhancement. Thereafter she was transferred to our hospital. A spine MRI revealed spinal dissemination. She underwent a dura mater biopsy, and the pathological analysis led to the diagnosis of PDL PNET. She received chemotherapy consisting of vincristine, cyclophosphamide, etoposide, cisplatin, and intrathecal methotrexate injections two months after the initial presentation. The progressive hydrocephalus was managed with external ventricular drainage. Two weeks after the first cycle of chemotherapy the hydrocephalus resolved, and the external ventricular drainage was removed. A follow-up MRI showed that the leptomeningeal enhancement decreased during the four cycles of chemotherapy without radiotherapy. The patient is scheduled to receive high-dose chemotherapy as consolidation therapy.

CONCLUSION

PDL PNET is extremely rare, and its diagnosis is often delayed. Treatment of PDL PNET is very difficult due to its aggressive course, and surgical resection is impossible. Early diagnosis may help improve outcomes.

HGG-49. A PEDIATRIC THALAMIC HIGH-GRADE GLIOMA WITH H3F3A K27M AND BRAF V600E DOUBLE MUTATIONS

CASE

A 18-month-old boy presented with approximately 2 months history of progressive left hemiparesis and left exotropia. MRI study showed a 3–4 cm T1-iso, T2-high tumor at right thalamus to midbrain with little contrast enhancement. The patient underwent endoscopic biopsy of the tumor, which showed relatively dense proliferation of small cells with round nuclei, mitosis of the tumor cell, but no necrosis. Immunohistochemical showed positive stain of GFAP and Olig2. Ki-67 was 34%. The histopathological diagnosis was compatible with high grade glioma. Chemotherapy with vincristine, cyclophosphamide, cisplatin and etoposide was initiated. Molecular testing of the tumor revealed H3F3A K27M and BRAF V600E double mutations in DNA from frozen tumor tissue.

DISCUSSION

The concurrent mutation of H3F3A K27M and BRAF V600E in pediatric glioma is very rare, but there are several cases previously reported in literature. Interestingly those cases are heterogenous in age, location, histopathological subtypes and clinical outcome.

GCT-14. SECOND-LOOK SURGERY FOR INTRACRANIAL GERM CELL TUMORS

OBJECTIVE

The authors present their experiences of second-look surgery in patients with intracranial GCTs who showed less than complete response despite normalizing or decreasing tumor markers after chemotherapy.

METHODS

Retrospective review of 14 patients who underwent second-look surgery for an intracranial GCT was performed.

RESULTS

Of 40 consecutive patients with newly diagnosed intracranial GCTs treated between August 2003 and 2019, 14 patients (35%) underwent second-look surgery. The mean age was 9.2 years. The initial diagnoses were mixed germ cell tumor in 6, immature teratoma in 4, yolk sac tumor in 2, and germinoma 2. Second-look surgery was performed after 1–3 courses of chemotherapy. Magnetic resonance imaging (MRI) at the surgery demonstrated increasing residual tumor in 8 and stable residual tumor in 6. Tumor markers were normalized in 10 and nearly-normalized in 4. Gross total resection was achieved in 12 patients and near-total resection in 2. Histopatholgy at second-look surgery revealed mature teratoma in 6, immature teratoma in 3, fibrosis with atypical cells in 2, and fibrosis in 3. Eleven patients subsequently underwent additional chemo-radiation therapy according to the initial diagnosis. All patients are alive with no evidence of recurrence with a mean follow-up of 69 months.

CONCLUSIONS

Second-look surgery plays an important role in the treatment of intracranial GCTs. Surgery may be encouraged at a relatively early phase after chemotherapy when the residual tumor increases or does not change the size despite normalized or nearly-normalized tumor markers in order to achieve complete resection and improve the outcome.

SURG-17. CLINICAL CHARACTERISTICS AND OUTCOMES OF EPILEPSY-RELATED BRAIN TUMOR IN CHILDREN

OBJECTIVE

Epilepsy is one of the earliest symptoms in pediatric brain tumor. Gross total resection (GTR) of the tumor does not necessarily achieve seizure free, therefore it is controversial whether surrounding epileptic foci should be resected at the initial surgery. The aims of this study are to report clinical characteristics and outcome of pediatric epilepsy-related brain tumor (ERBT) and to discuss treatment strategy.

METHODS

Subjects were children less than 18 years old who underwent surgery for ERBT. Patients in whom epilepsy had been controlled before surgery were excluded. Data were collected from medical record and retrospectively reviewed.

RESULTS

Twenty-one children (8 boys and 13 girls) were analyzed in this study. The mean age at surgery was 6.8 years. Tumor was astrocytic tumor in 10, gangliogioma in 4 and dysembryoplastic neuroepithelial tumor in 3. Intracranial subdural electrodes were placed prior to tumor resection in 5 cases. GTR was achieved in 14 (67%). Seizure free was achieved in 15 (71.4%). GTR was significantly associated with seizure free (p=0.002).

CONCLUSION

In most of ERBT, seizure free can be achieved by lesionectomy alone. However, the resection of surrounding epileptic foci is required in some cases. Detailed examinations to detect the epileptic foci should be performed in ERBT, particularly in case of drug-resistant intractable epilepsy.

Surgical outcomes by sectioning a filum terminale in patients with terminal syringomyelia

BACKGROUND

Although terminal syringomyelia suggests a tethered spinal cord, a consensus has still not been established for surgical indications, when there are no associated abnormalities or only minor associated abnormalities. We analyzed surgical outcomes of sectioning a filum terminale in patients with terminal syringomyelia to elucidate the significance of untethering surgery.

METHODS

Fifty-seven pediatric patients with terminal syringomyelia who underwent untethering via sectioning the filum terminale between 2007 and 2018 were retrospectively analyzed. Postoperative outcomes of symptoms and MRI findings were evaluated.

RESULTS

Of 57 patients, 40 had other associated abnormalities (25 with filar lipoma and 29 with low conus medullaris) that could be responsible for tethered cord. Nineteen patients had symptoms. The mean age at the time of surgery was 18 months (3-96 months). The mean follow-up period was 3.3 years (1-9 years). Preoperative symptoms improved in 9 patients (47%) after surgery. At 1 year after the surgery, the size of syringomyelia decreased in 19 (33%), increased in 4 (8%), and did not change in 34 (69%) patients. Of 28 patients who were followed up for more than 3 years, the size decreased in 17 (61%), increased in 1 (4%), and did not change in 10 (35%).

CONCLUSION

When untethering was performed by sectioning a filum terminale, the size of terminal syringomyelia decreased in more than half of patients in the long term. Sectioning the filum terminale demonstrated the possibility of radiological and clinical improvement in patients with terminal syringomyelia.

Basal encephalocele: surgical strategy and functional outcomes in the Tokyo experience

OBJECTIVE

The basal encephalocele (BEC) is the rarest form of encephalocele, with an incidence of about 1/35,000 live births. The incidence of its subtype, sphenoidal BEC, is even lower at about 1/700,000 live births. The aim of this study was to propose the optimal surgical approach to repairing BEC, with special attention to the reconstruction of the skull base bone defect.

METHODS

Fourteen consecutive pediatric patients with BEC who underwent surgical repair between March 2004 and March 2020 (10 boys and 4 girls, age 25 days to 7 years, median age 4 months) were enrolled. The follow-up period of the surviving patients ranged from 53 to192 months (mean 119.8 months). The patient demographics, BEC subtypes, preoperative clinical condition, radiographic findings, surgical procedures, and postoperative course were retrospectively analyzed.

RESULTS

There were 4, 8, and 2 cases of sphenoidal BEC, sphenoethmoidal BEC, and ethmoidal BEC, respectively. The size of the bone defect was small in 3 patients, medium in 7, and large in 4 patients. All the patients with sphenoethmoidal and ethmoidal BEC showed associated congenital anomalies other than cleft palate. In total, 25 operations were performed. Two patients underwent multiple operations, whereas the remaining 9 patients received only 1 operation. The transoral transpalatal approach was the initial procedure used in all 14 patients. The transfrontobasal approach was applied as an additional procedure in 2 patients and as part of a 1-stage combined operation in 2 patients. Autograft bone alone was used for skull base reconstruction in 17 early operations. A titanium mesh/plate was used in the remaining 8 operations without any perioperative complications. All BECs were successfully repaired. Three patients died during the clinical course due to causes unrelated to their surgery. All but one of the surviving patients started growth hormone replacement therapy before school age.

CONCLUSIONS

Based on the authors' limited experience, the key to successful BEC repair involves circumferential dissection of the BEC and a firm reconstruction of the skull base bone defect with a titanium plate/mesh. The transoral transpalatal approach is a promising, reliable procedure that may be used in the initial operation. When a cleft palate is absent, transnasal endoscopic repair is recommended. The transfrontobasal approach should be reserved for cases with a huge BEC and other anomalies. Long-term prognosis is apparently favorable in survivors.

Radiologically occult cervical intradural dermal sinus tract: a case report and review of literature

We report the unusual case of a 7-month-old girl presenting with congenital cervical dermal sinus tract in which the intradural tract was not detected on preoperative imaging and was identified intraoperatively. Considering possible devastating sequelae of infection, excision of dermal sinus tract might be justified even in the case with radiologically undetected intradural tract.

Is the Postoperative Horizontal Decubitus Position Following Transection of a Tight Filum Terminale in Pediatric Patients Necessary? - A Retrospective Cohort Study

After untethering surgery of a tethered spinal cord of a tight filum terminale, patients are usually kept in the horizontal decubitus position to prevent cerebrospinal fluid (CSF) leakage. However, the optimal period for keeping these patients in this position has not been established yet. Surgical results in two groups of pediatric patients with a tight filum terminale were retrospectively analyzed. Group A was maintained in the horizontal decubitus position for 72 h and group B was managed without being kept in this position postoperatively. A total of 313 patients underwent sectioning of a tight filum terminale. Of these patients, 144 were maintained horizontally for 72 h postoperatively (group A) and 169 were managed without this position (group B). Among the patients who were maintained horizontally for 72 h, one (0.7%) developed pseudomeningocele. No patients experienced CSF leakage in this group. Among the patients who were not horizontal, one (0.6%) developed CSF leakage and one (0.6%) developed pseudomeningocele. Maintaining patients without restriction of their position does not appear to change the rate of postoperative CSF leakage or pseudomeningocele. This suggests that maintaining patients horizontally after transection of a tight filum terminale is not necessary for preventing CSF leakage.

Neoadjuvant chemotherapy for atypical teratoid rhabdoid tumors (AT/RTs)

PURPOSE

Atypical teratoid rhabdoid tumor (AT/RT) is a rare, clinically highly malignant tumor. The extent of the surgical resection may affect survival. However, it is often difficult to perform gross total resection (GTR) at an initial surgery because of the large tumor size and high vascularity. Neoadjuvant chemotherapy may reduce not only the size but also the vascularity. We report our experience, review the literature, and analyze its effectiveness.

METHODS

A retrospective chart review of patients who underwent neoadjuvant chemotherapy and second-look surgery was performed. Demographic data, treatment courses, changes in tumor after the chemotherapy, extent of resection and estimated blood loss (EBL) during the second-look surgery, and outcome of each children were evaluated.

RESULTS

There are 4 cases. The average age at diagnosis was 13.3 months (2-30 months). Two to 4 courses of neoadjuvant chemotherapy were performed. MRI after the chemotherapy showed reduction of tumor volume, and tumor vascularity at the second-look surgery decreased in all cases. GTR was achieved in 3 cases, and NTR in 1 case. The mean EBL/estimated blood volume (EBL/EBV) was 21.3% (1.5-39%). The mean follow-up period was 23 months (2-48 months). At the last follow-up, 2 patients were alive without recurrence of the tumor (the follow-up periods were 48 and 16 months).

CONCLUSIONS

Neoadjuvant chemotherapy for AT/RTs might reduce both tumor size and vascularity, which enabled the maximal tumor resection. It may contribute to improve the prognosis of AT/RT through facilitating the tumor resection.

PEDT-04 SIX CASES OF RETINOBLASTOMA WITH CNS INVOLVEMENT

Although the survival rate of intraocular retinoblastoma (RB) is nearly 100%, the outcome of central nervous system (CNS) involvement or Trilateral retinoblastoma (TRb: very rare RB which associated with brain tumor) is dismal. We retrospectively reviewed our six cases of these rare tumors. Their ages at diagnosis are 0y3m-1y10m (median 1y3m) (Male 4, Female 2). Only one had RB family history. Their affected eyes were bilateral 2, unilateral 3 and no 1. Their CNS diseases were suprasellar tumor 3, pineal tumor 1 and cerebrospinal fluid (CSF) cytology positive 2. Two of the suprasellar tumor patients had spinal metastasis. Three of the six patients were TRb. One TRb patient was treated with chemotherapy and high-dose chemotherapy without radiotherapy. Although he suffered with secondary osteosarcoma seven years later, he got complete remission and alive 5 years more without any tumor recurrence. The second TRb patient was treated with chemotherapy and local radiotherapy but relapsed 20 months later. The third TRb patient was chemotherapy resistant. Two CSF positive patients had optic nerve invasion. One patient with chiasm invasion died 11 months later because of treatment resistance. The other patient with optic nerve invasion before optic canal had no CNS tumor nor CSF involvement at diagnosis. Chemotherapy before enucleation was given to avoid dissemination. However, CSF cytology became positive after enucleation and remained even with intensified chemotherapy. Finally, he got remission with radiotherapy and high-dose chemotherapy, and alive without disease for 3.8 years. The last patient had suprasellar genetically classified retinoblastoma tumor and cerebrospinal metastasis. This patient showed good chemotherapy response and is still under treatment. Even with &quotso called° fatal RB cases, some case could survive with intensified therapy. Data accumulation is necessary for better survival of these tumors.

Long-term outcomes in pediatric unruptured brain arteriovenous malformation treated by nonconservative management: a single center analysis

PURPOSE

The best management of pediatric unruptured brain arteriovenous malformations (ubAVM) should be further elucidated.

METHODS

Pediatric patients who presented to our facility with ubAVM and were treated nonconservatively were retrospectively analyzed regarding demographics, presenting symptoms, AVM characteristics, treatment modality, and outcome.

RESULTS

Thirteen patients were included. There were 9 male and 4 female patients with an average age (± SD) of 7.8 ± 4.6 years. The most common presenting symptom was seizure. The mean Spetzler Martin (SM) grade was 3.2. Seven patients were treated by surgical excision, 8 by embolization, 6 by radiosurgery, and during the mean follow-up period of 8.9 years (2.6-14.4 years), there were no hemorrhage. Complete ubAVM obliteration was achieved in all 7 patients (100%) who underwent surgical excision. AVM was obliterated in 5 out of 9 patients whose SM grade was 3 or 4. Modified Rankin scale was good (mRS 0-2) in all 13 patients.

CONCLUSIONS

Since the lifetime hemorrhage rate of pediatric ubAVM is high, it may be better to proceed with nonconservative treatment, especially when surgical excision is amenable. Nonconservative treatment could be an appropriate treatment with acceptable neurological outcome even in those with moderate to high-grade AVMs in selected cases.

Pediatric intracranial lower cranial nerve schwannoma unassociated with neurofibromatosis type 2: case report and review of the literature

INTRODUCTION

Pediatric schwannomas are rare, and most of them are associated with neurofibromatosis type 2 (NF2) and usually located in the vestibular nerve. Herein, we present the first pediatric case of intracranial schwannoma derived from the IX/X nerve complex unrelated to NF2.

CASE REPORT

The patient was a 9-year-old boy who presented with a 3-month history of headache and nausea. There was no family history of NF2. Imaging studies revealed a cystic lesion with enhanced wall in the left cerebellomedullary fissure. During the operation, the IX/X nerve complex was strongly adhered to the tumor at the jugular foramen. The tumor was totally excised, and the postoperative MRI demonstrated no residual tumor. Histopathological diagnosis was schwannoma. Genetic analysis revealed no mutation associated with NF2 and schwannomatosis.

CONCLUSION

We reported the first case of pediatric lower cranial nerve schwannoma which was not associated with NF2. The schwannoma should be included as differential diagnosis of pediatric posterior fossa tumors.

Characteristics of Recurrent Congenital Sinus Pericranii: Case Report and Review of the Literature

INTRODUCTION

Sinus pericranii (SP) involves transosseous vessels that connect the intra- and extracranial venous systems. Accessory-type SP can be cured by surgical or endovascular treatment. Reports of recurrence are, however, rare.

CASE

A boy presented with a soft-tissue mass on the left parietal region of the head. Computed tomography and magnetic resonance imaging revealed the congenital SP with several small transosseous vessels surrounded by an area of thin bone. At the initial surgery, the vascular mass was completely excised by coagulating and cutting the -transosseous vessels. The skull defect was filled with bone wax. Two years later, SP recurred at the same site. At the second surgery, the skull defect and surrounding area were sealed with acrylic resin. The boy has been followed up for 6 years without recurrence.

DISCUSSION

Potential risk factors for recurrence proposed in the existing literature include an unusually large number of emissary veins, rich circulation between intra- and extracranial venous systems, large bone defects, raised intracranial pressure, and association of other developmental venous anomalies. Our case demonstrates that thin skull bone around the original lesion can be another risk factor for recurrence.

CONCLUSION

Removing all abnormal vessels and sealing the skull defect as well as the surrounding thin bone area are important to prevent recurrence of congenital SP.

Long-term follow-up for patients with infantile hydrocephalus treated by choroid plexus coagulation

OBJECTIVEShunt surgery is the most common treatment for hydrocephalus, but it is associated with several long-term complications. Endoscopic choroid plexus coagulation (CPC) and endoscopic third ventriculostomy (ETV) are alternative surgeries that may avoid the need for shunt surgery. Although the short-term efficacy and safety of CPC have been reported in previous studies, long-term outcome, including not only avoiding shunt placement but also intellectual development, remains to be elucidated. The purpose of the present study was to investigate the long-term outcome of CPC.METHODSThe study population comprised patients who had infantile hydrocephalus treated by endoscopic CPC before the age of 24 months and who were followed until at least 5 years of age. Retrospective review was performed using the medical charts. The authors assessed educational status and the full-scale intelligence quotient (FSIQ) using the Wechsler Intelligence Scale for Children (WISC) IV as the means to evaluate the intellectual development.RESULTSFourteen patients with infantile hydrocephalus underwent CPC with or without ETV as a primary surgery. There were no intraoperative complications. In 7 patients (50%), hydrocephalus was successfully controlled without shunt placement. Six patients (43%) eventually required shunt placement. In one patient hydrocephalus was controlled by additional ETV. In the shunt-independent group, 4 patients went to age-appropriate school or achieved age-appropriate development according to intelligence quotient (IQ), 1 patient went to specialized school, and 2 patients had disabilities. In the shunt-dependent group, 4 patients went to an age-appropriate school or achieved age-appropriate development by IQ, 1 patient went to specialized school, and 1 patient had disabilities. The mean FSIQ score in 3 patients without shunts was 90 (range 89-91) and the mean FSIQ score in 4 patients with shunts was 80 (range 48-107). There was no significant difference in the rate of normal development between the shunt-independent group and the shunt-dependent group (p = 0.72).CONCLUSIONSThe CPC with or without ETV can be a safe and effective treatment in children with infantile hydrocephalus. Long-term control of hydrocephalus and normal intellectual development can be achieved in successful cases. Further prospective studies should be required to elucidate appropriate indications.

The long-term outcomes of endoscopic third ventriculostomy in pediatric hydrocephalus, with an emphasis on future intellectual development and shunt dependency

OBJECTIVEThe goal of this study was to clarify the long-term outcome of endoscopic third ventriculostomy (ETV) in pediatric hydrocephalus in light of the ETV Success Score (ETVSS), shunt dependency, and intellectual development.METHODSThe authors retrospectively analyzed pediatric patients with hydrocephalus who underwent ETV between 2002 and 2012 and who were followed for longer than 5 years as a single-center cohort. The data of the patients' pre- and postoperative status were collected. The relationships between ETVSS and the full-scale IQ as well as shunt dependency were analyzed. The usefulness of ETVSS for repeat ETV and the change of radiological parameters of ventricle size before and after ETV were also analyzed. The success of ETV was defined as no requirement for further CSF diversion procedures.RESULTSFifty ETVs were performed in 40 patients. The average ETVSS was 61 and the success rate at 6 months was 64%. The mean follow-up was 9.9 years (5.2-15.3 years), and the long-term success rate of ETV was 50%. The Kaplan-Meier survival curve continued to show a statistically significant difference among patients with a low, moderate, and high ETVSS, even after 6 months (p = 0.002). After 15 months from the initial ETV, no patients required additional CSF diversion surgery. There was no statistical significance between ETVSS and the long-term full-scale IQ or shunt dependency (p = 0.34 and 0.12, respectively). The radiological improvement in ventricle size was not associated with better future educational outcome.CONCLUSIONSThe ETVSS was correlated with the long-term success rate. After 15 months from the initial ETV, no patients required an additional CSF diversion procedure. The ETVSS was not considered to be correlated with long-term intellectual status.

Surgical management of cervical spine deformity in chondrodysplasia punctata

OBJECTIVE Chondrodysplasia punctata (CDP), a rare skeletal dysplasia, can lead to cervical spine instability and deformity. However, an optimal neurosurgical intervention has yet to be established. Thus, a retrospective study was conducted to assess the efficacy of various surgical interventions for children with CDP. METHODS The authors retrospectively reviewed 9 cases of CDP in which cervical decompression with or without posterior fusion was performed between April 2007 and May 2016. Patient demographics, preoperative clinical conditions, radiographic findings, surgical procedures, and the postoperative course were analyzed in detail. RESULTS A total of 12 operations were carried out in 9 patients (8 male, 1 female) during the study period. The patients' ages at the initial surgery ranged from 2 months to 2 years. Seven of the children had CDPX1, 1 had CDPX2, and 1 had tibia-metacarpal type CDP (CDP-TM). The lesion occurred at the craniovertebral junction (CVJ) in 7 cases and involved a subaxial deformity in 2 cases. The initial surgery was C-1 laminectomy with occipitocervical fusion (OCF) followed by halo external fixation in 5 cases, OCF alone in 1 case, and C-1 laminectomy alone in 3 cases. Three children required additional surgery. In one of these cases, a staged operation was required because the patient's head was too small to attach a halo ring at the time of the initial procedure (C-1 laminectomy). In another case, OCF was performed 11 months after C-1 laminectomy because of intramedullary signal change on serial MRI, although the child remained asymptomatic. In the third case, additional posterior fusion was performed 17 months after an initial laminectomy and OCF due to newly developed cervical dislocation caudal to the original fusion. This last patient required a third operation 9 months after the second because of deep wound infection. Surgery improved the motor function of all 7 children with CDPX1, but 3 children who had already suffered respiratory failure preoperatively required continued respiratory support. At the time of this report, 7 of the 9 children were alive and in stable condition. One child died due to restrictive respiratory insufficiency, and another died in an accident unrelated to CDP. CONCLUSIONS Surgical decompression with or without fusion for CVJ and subaxial cervical lesions in infants and toddlers with CDP generally saves lives and increases the likelihood of motor function recovery. However, in this case series the patients' preoperative condition had a strong effect on postoperative respiratory function. The surgery was not straightforward, and a second operation was required in some cases. Nevertheless, the findings indicate that early surgical intervention for CDP with cervical involvement is feasible, suggesting that the role of neurosurgery should be reevaluated.

Radiologically occult medulloblastoma with hydrocephalus: case report

INTRODUCTION

There have been no reports of occult medulloblastoma nor noncommunicating hydrocephalus due to radiologically occult brain tumors. Herein, we report radiologically occult medulloblastoma with noncommunicating hydrocephalus.

CASE REPORT

A 3-year-old boy presented with macrocephaly, visual field constriction, and papilledema. Neuroimagings showed enlargement of the ventricles without any mass lesions. The CT cisternography did not show influx of the contrast into the ventricles, which suggested local cerebrospinal fluid (CSF) circulatory disturbance at the outlet of the fourth ventricle. Due to possible obstructive nature of hydrocephalus, endoscopic third ventriculostomy (ETV) was performed. Three months after the ETV, he presented with repeated vomiting. Neuroimagings showed a 3-cm fourth ventricular mass with progressive hydrocephalus. Surgical resection was performed, which revealed the pathology was medulloblastoma.

CONCLUSION

We report the case of radiologically occult medulloblastoma which was demonstrated radiologically in the follow-up period of ETV for noncommunicating hydrocephalus of uncertain etiology. This is the first description of a radiologically occult medulloblastoma and also the first description of an occult brain tumor with noncommunicating hydrocephalus. The occult brain tumor may be included in the etiology of hydrocephalus.

New classification of spinal lipomas based on embryonic stage

OBJECTIVE Spinal lipomas are generally thought to occur as a result of failed primary neurulation. However, some clinical features cannot be explained by this theory. The authors propose a novel classification of spinal lipomas based on embryonic changes seen during primary and secondary neurulation. METHODS A total of 677 patients with occult spinal dysraphism underwent 699 surgeries between August 2002 and May 2015 at the National Center for Child Health and Development and Tokyo Metropolitan Children's Medical Center. This group of patients had 378 spinal lipomas, including 119 conus spinal lipomas, 27 lipomyelomeningoceles, and 232 filum lipomas, which the authors classified into 4 types based on neural tube formation during embryonic development. Type 1 is defined as pure primary neurulation failure; Type 2 ranges from primary to secondary neurulation failure; Type 3 consists of secondary neurulation failure (early phase); and Type 4 is defined as secondary neurulation failure (late phase). The authors also review embryogenesis in secondary neurulation and analyze the clinical utility of the new classification. RESULTS There were 55 Type 1 spinal lipomas, 29 Type 2, 62 Type 3, and 232 Type 4. All filum lipomas fell into the Type 4 spinal lipoma category. Association with anorectal and/or sacral anomalies was seen in none of the Type 1 cases, 15 (52%) of Type 2, 35 (56%) of Type 3, and 31 (13%) of Type 4. Urogenital anomalies were observed in none of the Type 1 or Type 2 cases, 1 (2%) of Type 3, and 28 (12%) of Type 4. Anomaly syndromes were present in none of the Type 1 cases, 6 (21%) of Type 2, 3 (5%) of Type 3, and 16 (7%) of Type 4. Associated anomalies or anomaly syndromes were clearly observed only for Type 2-4 spinal lipomas encompassing failed secondary neurulation. Radical resection was feasible for Type 1 spinal lipomas. CONCLUSIONS Secondary neurulation of the spinal cord gives rise to the conus medullaris and filum terminale, which are often involved in spinal lipomas. Formation of spinal lipomas seems to be a continuous process overlapping primary and secondary neurulation in some cases. Association with other anomalies was higher in Type 2-4 spinal lipomas, which included failed secondary neurulation, than in Type 1 lipomas, with failed primary neurulation. On the other hand, radical resection was indicated for Type 1, but not for Type 2, spinal lipomas. The new classification of spinal lipomas based on embryonic stage has the potential for clinical use and agrees well with both clinical and surgical findings. The classification proposed here is still preliminary. Further studies and verification are necessary to establish its clinical utility.

Pediatric intraventricular arachnoid cysts in the body of lateral ventricle: surgical outcome and its embryologic background

PURPOSE

The aim of this study is for the surgical treatment and outcome of the endoscopic fenestration of the arachnoid cyst located in the ventricular body to trigone in the pediatric population. Special concern was paid for the developmental origin of the intraventricular cysts estimated from the postoperative follow-up neuroimagings.

PATIENTS AND METHODS

Between July 2002 and June 2015, we performed endoscopic and partly CT/MRI navigated fenestrations of intraventricular arachnoid cysts located at the body to trigone of the lateral ventricle in ten pediatric patients aged 2 months to 5 years. Based on the long axis of the cyst, we have opted for two surgical approaches: anterior approach via burr hole at Kocher's point and posterior approach via burr hole at the posterior occipital region. Fenestration was performed based on the intraoperative findings, either ventriculocystostomy, ventriculocystoventriculostomy, or ventriculocystocisternostomy.

RESULTS

Intraventricular arachnoid cysts located in the body-trigone region showed a favorable outcome after endoscopic fenestration. All of the cysts shrank postoperatively. Follow-up neuroimagings taken between 6 and 126 months after surgery strongly suggested its relationship with the midline cisterns. Of our ten cases, eight were suggestive for originating from the velum interpositum cistern while two seemed to root from the quadrigeminal cistern.

CONCLUSION

In the present study, we found that endoscopic fenestration of intraventricular arachnoid cysts in the body to trigone is a safe procedure with a satisfactory outcome. In our limited experience, there are two anatomic backgrounds; velum interpositum cistern and quadrigeminal cistern. Differentiation can be possible by neuroimagings, especially those obtained after surgery.

Endoscopic third ventriculostomy for hydrocephalus in brainstem glioma: a case series

OBJECT

A brainstem glioma is an incurable brain tumor that can be complicated by hydrocephalus. A ventriculoperitoneal (VP) shunt is generally performed for the control of hydrocephalus. This study aimed to reveal the safety and efficacy of an endoscopic third ventriculostomy (ETV) for hydrocephalus in brainstem gliomas.

METHODS

Six patients who had pontine glioma with hydrocephalus underwent an ETV between May 2010 and November 2015. In all the cases, there were one or more symptoms of hydrocephalus (headache, nausea, vomiting, or lethargy). Retrospective review of these patients was performed using the medical records and neuroimagings.

RESULT

The ETV was performed safely and there were no intraoperative complications in all patients. The mean follow-up period was 12.3 months. An immediate symptomatic relief of hydrocephalus and an adequate control of symptoms were achieved without a VP shunt in all patients.

CONCLUSIONS

The ETV is considered to be an effective and safe procedure for the treatment of hydrocephalus in brainstem gliomas. Determining the ventriculostomy site according to the preoperative MRI in each case is considered to be important for the safe procedure.

Second-Look Surgery for Intracranial Germ Cell Tumors

BACKGROUND:

The role of second-look surgery in intracranial germ cell tumors (GCTs) needs to be reviewed.

OBJECTIVE:

To present our experience of second-look surgery in patients with intracranial GCTs who showed less than complete response despite normalizing or decreasing tumor markers after chemotherapy.

METHODS:

Retrospective review of 7 patients who underwent second-look surgery for an intracranial GCT was performed.

RESULTS:

Of 23 consecutive patients with newly diagnosed intracranial GCTs treated between August 2003 and August 2013, 7 patients (30%) underwent second-look surgery. The mean age was 9.4 years. The initial diagnoses were mixed germ cell tumor in 5 and immature teratoma in 2. Second-look surgery was performed after 1 to 3 courses of chemotherapy. Magnetic resonance imaging at the surgery demonstrated increasing residual tumor in 4 and stable residual tumor in 3. Tumor markers were normalized in 5 and nearly normalized in 2. Gross total resection was achieved in all patients. Histopathology at second-look surgery revealed mature teratoma in 5, fibrosis with atypical cells in 1, and fibrosis in 1. All patients subsequently underwent additional chemoradiation therapy according to the initial diagnosis. All patients are alive with no evidence of recurrence, with a mean follow-up of 48 months.

CONCLUSION:

Second-look surgery plays an important role in the treatment of intracranial GCTs. Surgery may be encouraged at a relatively early phase after chemotherapy when the residual tumor increases or does not change size despite normalized or nearly normalized tumor markers in order to achieve complete resection and improve outcome.

Neoadjuvant chemotherapy for brain tumors in infants and young children

OBJECT

Because of their large size and high vascularity, complete removal of brain tumors in infants and young children is often difficult. In most cases the degree of resection is associated with prognosis. Neoadjuvant chemotherapy may facilitate resection by reducing the vascularity of the tumor. The authors evaluated the effectiveness of neoadjuvant chemotherapy in the management of these tumors.

METHODS

The authors performed a retrospective review of infants and young children who underwent tumor removal after neoadjuvant chemotherapy.

RESULTS

Nine consecutive patients underwent resection after neoadjuvant chemotherapy during the period February 2004 to December 2012. The mean age at diagnosis was 18 months (range 2-50 months). The average largest tumor diameter was 71 mm (range 30-130 mm) at initial surgery. Five patients underwent partial resection, and 4 underwent biopsy as the initial surgery. The histopathological diagnoses were ependymoma in 2 patients, anaplastic ependymoma in 1, primitive neuroectodermal tumor (PNET) in 2, choroid plexus carcinoma in 1, atypical teratoid/rhabdoid tumor (AT/RT) in 1, glioblastoma in 1, and embryonal tumor with abundant neuropil and true rosettes in 1. After 2-4 courses of multiagent chemotherapy (mainly with vincristine, cyclophosphamide, etoposide, and cisplatin), the second-look surgery was performed. In 1 patient with a PNET, intratumoral hemorrhage was observed after 2 courses of chemotherapy. The mean interval between the initial and the second-look surgery was 3 months. The tumor volume was reduced to varying degrees in 5 patients (56%) after chemotherapy. Intraoperatively, the vascularity of the tumor was considerably reduced, and the tumor was more circumscribed in all cases. Gross-total resection was achieved in 8 patients (89%) and neartotal resection in 1 (11%). Histopathological examination demonstrated fibrotic tissue circumscribing the tumor in 6 of 9 cases (67%). The average blood loss was 20% of the estimated blood volume, and 3 patients (33%) required a blood transfusion. There was no surgical mortality. One patient had transient dysphasia postoperatively. The mean follow-up period was 28 months. At the last follow-up, 2 patients (22%) had died (1 died of tumor progression and 1 of sepsis), and 4 patients (44%) had no tumor recurrence.

CONCLUSIONS

Neoadjuvant chemotherapy for brain tumors in infants and young children was effective in reduction of tumor vascularity and clarification of the tumor-brain interface, which significantly facilitated maximal tumor resection.

Duration of the horizontal decubitus position for prevention of cerebrospinal fluid leakage following transection of a tight filum terminale

OBJECT

The untethering of a tethered spinal cord in patients with a tight filum terminale is a relatively simple procedure that can prevent or improve neurological symptoms. Postoperatively, patients are usually kept in the horizontal decubitus position to prevent a CSF leak. However, the optimal period for keeping patients flat has not been determined yet. The authors compared 2 cohorts with different periods of horizontal decubitus; one with 72 hours and the other with 8 days.

METHODS

The authors retrospectively analyzed surgical results in 2 cohorts of pediatric patients who had tethered spinal cord with a tight filum terminale. One cohort was maintained flat for 8 days and the other cohort for 72 hours postoperatively. The patients' charts were reviewed for demographic data, clinical presentation, surgical therapy, and clinical course.

RESULTS

Three hundred fifty-four patients underwent sectioning of a tight filum terminale. Of those, 238 were kept lying flat for 8 days postoperatively, and 116 were maintained flat for 72 hours. Magnetic resonance imaging was performed 1 to 2 weeks after the surgery. None of the patients in either cohort developed a CSF leak. Pseudomeningocele, which was confirmed by MRI, developed in 1 patient who had been kept flat for 8 days. The occurrence rates of a CSF leak and pseudomeningocele were not significantly different in either cohort.

CONCLUSIONS

Keeping patients flat for longer than 72 hours did not change the rate of postoperative CSF leakage or pseudomeningocele. Seventy-two hours or less would be an appropriate period for maintaining patients flat after transection of a tight filum terminale.