Viral infections of the pediatric central nervous system (CNS) encompass a broad spectrum of both perinatally and postnatally acquired diseases with potentially devastating effects on the developing brain. In children, viral infections have been associated with chronic encephalopathy, encephalitis, demyelinating disease, tumors, and epilepsy. Older diagnostic techniques of biopsy, viral culture, electron microscopy, gel-based polymerase chain reaction (PCR), and viral titer quantification are being replaced with more rapid, sensitive, and specific real-time and microarray-based PCR technologies. Advances in neuroimaging technologies have provided for earlier recognition of CNS injury without elucidation of specific viral etiology. Although the mainstay therapy of many pediatric neurovirologic diseases, aside from HIV, includes intravenous acyclovir, much work is being done to develop novel antiviral immunotherapies aimed at both treating and preventing pediatric CNS viral disease.

Introduction

The object of this review is to describe the choroid plexus tumors (CPTs) occurring in the fetus and neonate with regard to clinical presentation, location, pathology, treatment, and outcome.

Materials and methods

Case histories and clinical outcomes were reviewed from 93 cases of fetal and neonatal tumors obtained from the literature and our own institutional experience from 1980 to 2016.

Results

Choroid plexus papilloma (CPP) is the most common tumor followed by choroid plexus carcinoma (CPC) and atypical choroid plexus papilloma (ACPP). Hydrocephalus and macrocephaly are the presenting features for all three tumors. The lateral ventricles are the main site of tumor origin followed by the third and fourth ventricles, respectively. CPTs of the fetus are detected most often near the end of the third trimester of pregnancy by fetal ultrasound. The extent of surgical resection plays an important role in the treatment and outcome. In spite of excellent survival, which is especially true in the case of CPP, surgical resection may carry significant risks in an immature baby. Given the neonatal low blood volume and increased vascularity of the tumors, there is potential risk for hemorrhage. Although advances in neurosurgical techniques have led to a greater degree of complete surgical resections, survival for the perinatal CPC group remains low even with multimodality therapies.

Conclusion

Perinatal CPTs have variable overall survivals depending on degree of surgical resection and tumor biology. An increased understanding of the molecular features of these tumors may lead to improved therapies and ultimately survival.

Primary central nervous system (CNS) tumors cause significant morbidity and mortality in both adults and children. While some of the genetic and molecular mechanisms of neuro-oncogenesis are known, much less is known about possible epigenetic contributions to disease pathophysiology. Over the last several decades, chronic viral infections have been associated with a number of human malignancies. In primary CNS malignancies, two families of viruses, namely polyomavirus and herpesvirus, have been detected with varied frequencies in a number of pediatric and adult histological tumor subtypes. However, establishing a link between chronic viral infection and primary CNS malignancy has been an area of considerable controversy, due in part to variations in detection frequencies and methodologies used among researchers. Since a latent viral neurotropism can be seen with a variety of viruses and a widespread seropositivity exists among the population, it has been difficult to establish an association between viral infection and CNS malignancy based on epidemiology alone. While direct evidence of a role of viruses in neuro-oncogenesis in humans is lacking, a more plausible hypothesis of neuro-oncomodulation has been proposed. The overall goals of this review are to summarize the many human investigations that have studied viral infection in primary CNS tumors, discuss potential neuro-oncomodulatory mechanisms of viral-associated CNS disease and propose future research directions to establish a more firm association between chronic viral infections and primary CNS malignancies.

INTRODUCTION:Seizure is a common comorbidity in patients with brain tumor. It may be the presenting symptom or develop after the tumor diagnosis. The underlying pathophysiology of brain tumor-related epilepsy remains poorly understood. METHODS:A comprehensive literature review of Pubmed English articles from 1980-2017 was performed to summarize current knowledge and treatment options of brain tumor-related epilepsy. RESULTS:Multiple factors have been found to contribute to tumor-related epilepsy, including tumor type, speed of tumor growth, location, and tumor burden. The underlying pathogenesis of epilepsy is not clear but perturbations in the peri-tumoral regions, both structural and cellular communications, have been implicated. CONCLUSIONS:Surgical and medical treatments of tumor-related epilepsy remain challenging as additional factors such as the extent of surgical resection, interactions with tumor-related oncological treatments and anti-epileptic medication related side effects need to be considered.

MEK inhibitors are an emerging therapy with increasing use in mitogen-activated protein kinase-driven central nervous system (CNS) tumors. There is limited data regarding efficacy and toxicity in pediatric patients. We report our clinical experience with trametinib-based therapy for the treatment of 14 consecutive pediatric patients with recurrent low-grade glioma (N=11) or high-grade CNS tumors (N=3) with MAP kinase pathway mutations. Patients received trametinib as monotherapy (N=9) or in combination (N=5) with another antineoplastic agent. Nine patients (64%) were progression free during treatment. Five patients showed a partial response, while 4 had stable disease. Two patients (14%) progressed on therapy. All partial responses were in patients with low-grade tumors. The remaining 3 patients were not evaluable due to toxicity limiting duration of therapy. Two of 3 patients with low-grade glioma with leptomeningeal dissemination showed radiographic treatment response. Five patients reported improved clinical symptoms while on trametinib. Adverse events on trametinib-based therapy included dermatologic, mouth sores, fever, gastrointestinal, infection, neutropenia, headache, and fatigue, and were more common in patients using combination therapy. Trametinib-based therapy demonstrated signals of efficacy in our single institutional cohort of pediatric patients with mitogen-activated protein kinase-driven CNS tumors. Our observations need to be confirmed in a clinical trial setting.

Background and Purpose- Stroke is a leading cause of long-term disability. Limited treatment options exist for patients with chronic stroke and substantial functional deficits. The current study examined safety and preliminary efficacy estimates of intravenous allogeneic mesenchymal stem cells in this population. Methods- Entry criteria included ischemic stroke >6 months prior and substantial impairment (National Institutes of Health Stroke Scale score ≥6) and disability. Enrollees received a single intravenous dose of allogeneic ischemia-tolerant mesenchymal stem cells. Phase 1 used a dose-escalation design (3 tiers, n=5 each). Phase 2 was an expanded safety cohort. The primary end point was safety over 1-year. Secondary end points examined behavioral change. Results- In phase 1 (n=15), each dose (0.5, 1.0, and 1.5 million cells/kg body weight) was found safe, so phase 2 subjects (n=21) received 1.5 million cells/kg. At baseline, subjects (n=36) averaged 4.2±4.6 years poststroke, age 61.1±10.8 years, National Institutes of Health Stroke Scale score 8 (6.5-10), and Barthel Index 65±29. Two were lost to follow-up, one was withdrawn and 2 died (unrelated to study treatment). Of 15 serious adverse events, none was possibly or probably related to study treatment. Two mild adverse events were possibly related to study treatment, a urinary tract infection and intravenous site irritation. Treatment was safe based on serial exams, electrocardiograms, laboratory tests, and computed tomography scans of chest/abdomen/pelvis. All behavioral end points showed significant gains over the 12-months of follow-up. For example, Barthel Index scores increased by 6.8±11.4 points (mean±SD) at 6-months (P=0.002) and by 10.8±15.5 points at 12-months (P<0.001) post-infusion; the proportion of patients achieving excellent functional outcome (Barthel score ≥95) increased from 11.4% at baseline to 27.3% at 6-months and to 35.5% at 12-months. Conclusions- Intravenous transfusion of allogeneic ischemia-tolerant mesenchymal stem cell in patients with chronic stroke and substantial functional deficits was safe and suggested behavioral gains. These data support proceeding to a randomized, placebo-controlled study of this therapy in this population. Clinical Trial Registration- URL: https://www.clinicaltrials.gov. Unique identifier: NCT01297413.

INTRODUCTION:Bevacizumab-based therapy has been demonstrated to be effective in the treatment of refractory or recurrent pediatric low-grade glioma (LGG); however its efficacy as a single agent is less understood. METHODS:We report our experience with single-agent bevacizumab for the treatment of recurrent or refractory LGG treated with either standard 2 week dosing (10 mg/kg/dose every 2 weeks) or with a standard 2 week dosing followed by an increased interval dosing (10 mg/kg/dose every 4 weeks). RESULTS:From 2012 to 2017, 15 patients (five males and 10 females) with recurrent/refractory LGG (nine suprasellar, three thalamic, two brainstem, and one intramedullary spinal cord) were treated with a total of 156 doses of bevacizumab (115 every 2 week dosing, 41 every 4 week dosing, median 10 doses). Patients were refractory to a median of one nonsurgical therapy (range 0-3) prior to treatment with bevacizumab. Twelve of 15 demonstrated radiographic response (three complete, nine partial, and three stable disease). Significant clinical responses including improved visual fields (four), cranial neuropathy (three3), strength (seven), and gait (two) were observed. Bevacizumab was discontinued in 12 patients (resolution, one; disease stability, seven; progression, two; toxicity, one; and other, one) and three patients continue to receive monthly bevacizumab. Eleven patients eventually had radiographic progression (median 5 months, range 0.5-31) without clinical progression, and four of five receiving bevacizumab rechallenge had lpartial response. CONCLUSION:Single-agent bevacizumab is efficacious in the management of recurrent or refractory pediatric LGG with radiographic and clinical responses similar to those reported for bevacizumab-based therapies.

BACKGROUND:Pediatric intracavernous sinus tumors are exceedingly rare and thus poorly characterized. Their neurosurgical management is challenging and diagnostic, and management guidelines are limited. OBJECTIVE:To report our institutional experience with the surgical resection of pediatric intracavernous sinus tumors. We also compare and contrast our results with the 14 cases of pediatric intracavernous sinus lesions in the current literature. METHODS:A retrospective descriptive analysis of consecutive pediatric patients (ages 0-18 yr) presenting to our institution with a diagnosis of an intracavernous sinus lesion was performed. From January 2012 to January 2017, 5 cases were identified. Eleven patients with secondary invasion of the cavernous sinus (2 meningiomas, 7 pituitary adenomas) or dermoid tumors involving the cavernous sinus (2) were not included in our review. RESULTS:Surgical resection via a frontotemporal orbitozygomatic approach was performed in all cases by a single senior neurosurgeon (M.L.). There were no perioperative or postoperative complications attributable to the surgery or approach. Four of 5 patients remained neurologically stable throughout the perioperative and postoperative period. The fifth patient had a complete resolution of their cranial neuropathies postoperatively. A pathological diagnosis that guided long-term management was obtained in all cases. CONCLUSION:Neurosurgical management of pediatric cavernous sinus lesions can be safely performed and critically guide future therapies. Surgeon familiarity with cavernous sinus and skull-base anatomy is critical to the successful management of these patients. The benefits of surgery should be balanced against the potential complications and need for a tissue diagnosis in children. The senior author had a significant experience with cavernous sinus approaches in adults prior to initiating use of the approach in the pediatric population.

Successful use of immune checkpoint inhibitors in a variety of cancers has generated interest in using this approach in pediatric brain tumors. We performed a retrospective review of 10 consecutive children (6 boys, 4 girls; ages, 2 to 17 y), with recurrent or refractory pediatric brain tumors (5 high-grade glioma, 1 low-grade glioma, pineoblastoma, medulloblastoma, ependymoma, and CNS embryonal tumor, NOS) treated at Rady Children's Hospital San Diego from 2015 to 2017 with the immune checkpoint inhibitor nivolumab (3 mg/kg every 2 wk). Eight of 10 patients received prior chemotherapy and 9 radiation therapy. Nine patients had radiographic disease progression (median, 2.5 doses). Median time to progression was 5.5 weeks (1.6 to 24 wk). Three patients (2 with high-grade glioma, 1 with CNS embryonal tumor NOS) showed a partial response to treatment at the primary tumor site and 2 of 3 had progression of metastatic disease. Grade 2 toxicities were observed without dose limiting side effects. Tumor mutation burden (TMB) was low to intermediate (median, 1.3; range, 0 to 6.3). Median survival for PD-L1 positive patients was 13.7 weeks versus 4.2 weeks for PD-L1 negative patients (ρ=0.08) nivolumab was well tolerated in our series of pediatric recurrent brain tumors with some transient partial responses in patients with positive PD-L1 expression and higher TMB. Our findings suggest that the use of immune checkpoint inhibitors in pediatric brain tumor patients should be limited to those with elevated PD-L1 expression and TMB.

To determine the relationship between clinical presentation, radiographic features, pathology, and treatment on overall survival of newly diagnosed pediatric primary spinal cord tumors (PSCT). Retrospective analysis of all previously healthy children with newly diagnosed PSCT at a single institution from 1995 to present was performed. Twenty-five pediatric patients (15 boys, average 7.9 years) were diagnosed with PSCT. Presenting symptoms ranged from 0.25 to 60 months (average 7.8 months). Symptom duration was significantly shorter for high grade tumors (average 1.65 months) than low grade tumors (average 11.2 months) (P = 0.05). MRI revealed tumor (8 cervical, 17 thoracic, 7 lumbar, 7 sacral) volumes of 98–94,080 mm3 (average 19,474 mm3). Homogeneous gadolinium enhancement on MRI correlated with lower grade pathology (P = 0.003). There was no correlation between tumor grade and volume (P = 0.63) or edema (P = 0.36) by MRI analysis. Median survival was 53 months and was dependent on tumor grade (P = 0.05) and gross total resection (P = 0.01) but not on gender (P = 0.49), age of presentation (P = 0.82), duration of presenting symptoms (P = 0.33), or adjuvant therapies (P = 0.17). Stratified Kaplan–Meier analysis confirmed the association between degree of resection and survival after controlling for tumor grade (P = 0.01). MRI homogeneous gadolinium enhancement patterns may be helpful in distinguishing low grade from high grade spinal cord malignancies. While tumor grade and gross total resection rather than duration of symptoms correlated with survival in our series, greater than one-third of patients had reported symptoms greater than 6 months duration prior to diagnosis.