Radiation-Induced Moyamoya Syndrome in Children with Brain Tumors: Case Series and Literature Review

Advances in moyamoya disease: pathogenesis, diagnosis, and therapeutic interventions

Moyamoya disease (MMD) is a type of cerebrovascular disease characterized by occlusion of the distal end of the internal carotid artery and the formation of collateral blood vessels. Over the past 20 years, the landscape of research on MMD has significantly transformed. In this review, we provide insights into the pathogenesis, diagnosis, and therapeutic interventions in MMD. The development of high-throughput sequencing technology has expanded our understanding of genetic susceptibility, identifying MMD-related genes beyond RNF213, such as ACTA2, DIAPH1, HLA, and others. The genetic susceptibility of MMD to its pathological mechanism was summarized and discussed. Based on the second-hit theory, the influences of inflammation, immunity, and environmental factors on MMD were also appropriately summarized. Despite these advancements, revascularization surgery remains the primary treatment for MMD largely because of the lack of effective in vivo and in vitro models. In this study, 16 imaging diagnostic methods for MMD were summarized. Regarding therapeutic intervention, the influences of drugs, endovascular procedures, and revascularization surgeries on patients with MMD were discussed. Future research on the central MMD vascular abnormalities and peripheral circulating factors will provide a more comprehensive understanding of the pathogenic mechanisms of MMD.

Exploration of the risk factor for infarction after revascularization in moyamoya disease

RESULTS

Eventually, 108 consecutive patients received 174 surgeries were enrolled, experienced new or expanded infarction occured in 13 (7.47%) surgeries, which showed higher Suzuki stage on the non-operative side, more posterior cerebral artery (PCA) involvement, and more intraoperative hypotension compared to those without infarction(p < .05). The Suzuki stage on the non-operative side had the highest area under the curve (AUC) of 0.737, with a sensitivity of 0.692 and specificity of 0.783. Combination of the three factors showed better efficiency, with an AUC of 0.762, a sensitivity of 0.692, and a specificity of 0.907.

CONCLUSIONS

Revascularization was a safe option for patients with MMD, higher Suzuki stage on the non-operative side, PCA involvement, and intraoperative hypotension might be the risk factors for new or expanded infarction after revascularization in patients with MMD.

Long-term quality of survival after pediatric low-grade glioma

BACKGROUND

Low-grade glioma is the most common brain tumor in children with different modes of treatment and a high overall survival. Low-grade glioma is considered a chronic disease, since residual tumor is present in many children. The tumor and its treatment lead to acquired brain injury with diverse consequences for later life based on factors like the diverse tumor locations, treatment(s) applied, neurofibromatosis type 1, and age at diagnosis.

METHODS

An overview of affected domains is provided based upon cohort studies from literature and partially based on clinical experience with a practical approach regarding each domain of functioning in order to provide insight in the requirements for long-term care assistance after childhood low-grade glioma.

RESULTS

The diverse domains that can potentially be affected are described as follows: motor function, speech, eating and swallowing, sensory functions, seizures, neuropathy, organ function after systemic treatment, late effects due to cranial radiation (vascular changes and secondary tumors, endocrine and hypothalamic function, sleep and energy, neuro-cognition and education, psychosocial effects, and quality of life.

CONCLUSION

Insight in affected domains guides advices for medical follow-up, diagnostics, supportive instructions, and assistive measures per domain of functioning and provide insight in the requirements for long-term care assistance after childhood low-grade glioma.

Post-infectious Moyamoya Syndrome: A Review of Existing Scientific Literature From 2000 to 2023

Moyamoya disease (MMD) is considered a primary disorder of an unknown etiology. In contrast, Moyamoya syndrome (MMS) refers to MMD associated with other underlying diseases, such as meningitis in childhood, neurofibromatosis type II, Down syndrome, cranial irradiation, and different types of anemias, particularly hemoglobinopathies. We aimed to provide a comprehensive clinicopathological overview of MMS. All case reports and case series published from 2000 to 2023 pertaining to MMD were included in the study. Case studies, original articles, editorials, letters to editors, and clinical images were excluded. The search was conducted using the Boolean operators ("AND" and "OR") on PubMed and Google Scholar. A total of 13 case reports and one case series study were included. The study suggests infection might be a trigger in susceptible individuals. The autoimmune antibody findings (anti-double stranded DNA IgG) suggest a potential autoimmune component in some cases. There were diverse presentations and outcomes of post-infectious MMS, with a striking predominance of pediatric cases (66.66%) and a possible female predominance. Both computerized tomography (CT) and magnetic resonance imaging (MRI) showed evidence of restricted blood flow. CT showed that stenosis, occlusion, and collateral formation were frequent vascular findings, but often unspecified in severity. Infarction, hypodensities, and hematoma were the most common parenchymal findings (22.22% each). The findings on MRI were stenosis (50%) and collateral formation (44.44%). Infarction was the most common finding (66.66%) in parenchyma. Hydrocephalus, encephalomalacia, and atrophy were less frequent. Lesions were most frequent in the internal carotid artery (66.66%), middle cerebral artery (66.66%), and anterior cerebral artery (50%). Lesions were less frequent in the posterior cerebral, vertebral, and basilar arteries. The frontal lobe (38.89%) and basal ganglia (33.33%) were commonly affected parenchymal regions. The most common risk factor was human immunodeficiency virus (HIV) infection (50%), followed by trisomy 21, cryptococcal, and other types of meningitides. Aspirin (50%) and antiretroviral therapy (38.89%) were the cornerstones of treatment for MMS. This review accentuates the noteworthy obstacles presented by post-infectious MMS, especially its catastrophic effect on children and its correlation with HIV/AIDS. According to our elaborate literature search using PubMed and Google Scholar, this is the first narrative review in the existing scientific literature summarizing the literature on post-infectious MMS.

Neuropsychiatric Symptoms of Moyamoya Disease: Considerations for the Clinician

Neurocognitive impairment in moyamoya disease is common, under recognized, and potentially devastating. The purpose of this paper is to provide an updated overview on this topic for the practicing clinician. We searched PubMed for keywords including cognitive impairment, neurocognitive dysfunction, and neuropsychological recovery in moyamoya disease. We summarized the literature to provide a concise review of the treatment and management of neuropsychiatric symptoms associated with moyamoya disease. Neuropsychiatric sequelae have conventionally been attributed to chronic cerebral hypoperfusion and/or stroke. Cognitive dysfunction in adults with moyamoya disease is most commonly in the form of impaired executive function, whereas intelligence is the predominant impairment in children with moyamoya disease. Pharmacotherapy for treatment of the neuropsychiatric symptoms associated with moyamoya disease is appropriate and can improve quality of life; however, careful consideration is needed to avoid adverse cerebrovascular events. It remains unclear as to whether surgical revascularization improves or stabilizes cognitive performance and outcomes. Additional prospective studies are warranted to better understand the long-term impact of revascularization on cognitive functioning in moyamoya disease.

Rupture of a flow aneurysm secondary to spontaneous extracranial to intracranial revascularisation in the posterior fossa following radiation-induced vasculopathy for cerebellar tumour

Paediatric patients receiving cranial irradiation therapy for brain tumours are at increased risk of cerebrovascular complications. Radiation-induced moyamoya syndrome (MMS) is a well-recognised complication of this. We present a case of an 8-year-old boy with a history of medulloblastoma, who underwent surgical excision followed by post-operative adjuvant oncological treatment. Six years later, he developed cerebellar/intraventricular haemorrhage. He underwent an emergency external ventricular drain (EVD) insertion followed by posterior fossa suboccipital craniotomy. On dural opening, an abnormal vessel was visualised on the surface of the right cerebellar hemisphere, which was not disturbed. No obvious abnormalities were identified intra-operatively. Cerebral catheter angiography confirmed the presence of a right-sided occipital artery (OA) to posterior inferior cerebellar artery (PICA) extracranial to intracranial (EC-IC) bypass with a zone of the distal PICA territory supplied by this EC-IC bypass. A presumed flow aneurysm originated from the bypass in the distal PICA, identified as cause for the haemorrhage. We highlight a rare cause for intracranial haemorrhage in this cohort of patients. Children who have undergone radiotherapy may have exquisitely sensitive cerebral vasculature and need careful vigilance and evaluation for vasculopathic complications following spontaneous haemorrhage.

Approaches to Minimise the Neurodevelopmental Impact of Choroid Plexus Carcinoma and Its Treatment

Choroid plexus carcinomas (CPC) are rare aggressive tumours that primarily affect very young children. Treatment for CPC typically involves a combination of surgery, chemotherapy, and radiation therapy. Whilst considered necessary for a cure, these therapies have significant neurocognitive consequences for patients, negatively impacting cognitive function including memory, attention, executive functioning, and full-scale intelligence quotients (FSIQ). These challenges significantly impact the quality of life and ultimately socioeconomic parameters such as the level of educational attainment, marital status, and socioeconomic status. This review looks at the tumour- and treatment-related causes of neurocognitive damage in CPC patients and the progress made in finding strategies to reduce these. Opportunities to mitigate the neurodevelopmental consequences of surgery, chemotherapy, and radiation therapy are explored in the context of CPC treatment. Evaluation of the pathological and biological mechanisms of injury has identified innovative approaches to neurocognitive protection and neurorehabilitation, which aim to limit the neurocognitive damage. This review aims to highlight multiple approaches physicians can use when treating young children with CPC, to focus on neurocognitive outcomes as a measure of success.

Complications of Cancer Therapy in Children: A Comprehensive Review of Neuroimaging Findings

ABSTRACT

Complications of cancer therapy in children can result in a spectrum of neurologic toxicities that may occur at the initiation of therapy or months to years after treatment. Although childhood cancer remains rare, increasing survival rates mean that more children will be living longer after cancer treatment. Therefore, complications of cancer therapy will most likely occur with increasing frequency.At times, it is very difficult to differentiate between therapeutic complications and other entities such as tumor recurrence, development of secondary malignancy, and infection (among other conditions). Radiologists often play a key role in the diagnosis and evaluation of pediatric patients with malignancies, and thus, awareness of imaging findings of cancer complications and alternative diagnoses is essential in guiding management and avoiding misdiagnosis. The aim of this review article is to illustrate the typical neuroimaging findings of cancer therapy-related toxicities, including both early and late treatment effects, highlighting pearls that may aid in making the appropriate diagnosis.

Moyamoya Vasculopathy in Neurofibromatosis Type 1 Pediatric Patients: The Role of Rare Variants of RNF213

Neurofibromatosis type 1 (NF1) is a neurocutaneous disorder caused by mutations in NF1 gene, coding for neurofibromin 1. NF1 can be associated with Moyamoya disease (MMD), and this association, typical of paediatric patients, is referred to as Moyamoya syndrome (MMS). MMD is a cerebral arteriopathy characterized by the occlusion of intracranial arteries and collateral vessel formation, which increase the risk of ischemic and hemorrhagic events. RNF213 gene mutations have been associated with MMD, so we investigated whether rare variants of RNF213 could act as genetic modifiers of MMS phenotype in a pediatric cohort of 20 MMS children, 25 children affected by isolated MMD and 47 affected only by isolated NF1. By next-generation re-sequencing (NGS) of patients' DNA and gene burden tests, we found that RNF213 seems to play a role only for MMD occurrence, while it does not appear to be involved in the increased risk of Moyamoya for MMS patients. We postulated that the loss of neurofibromin 1 can be enough for the excessive proliferation of vascular smooth muscle cells, causing Moyamoya arteriopathy associated with NF1. Further studies will be crucial to support these findings and to elucidate the possible role of other genes, enhancing our knowledge about pathogenesis and treatment of MMS.

Acute ischemic stroke secondary to ventriculoperitoneal shunt dysfunction in a child with Moyamoya syndrome

Background:

Patients with brain vascular disease and hydrocephalus may be predisposed to acute ischemic stroke in case of shunt dysfunction and subsequent increased intracranial pression. Patients with brain tumor may develop hydrocephalus as a consequence of obstruction of cerebrospinal fluid pathways and radiation-induced moyamoya syndrome secondary (RIMS) to radiotherapy (RT).

Case Description:

A 15-year-old male patient, affected by hydrocephalus and RIMS, presented acute cerebral ischemia after an episode of shunt malfunction. The shunt was promptly revised and the areas of ischemia visible at magnetic resonance imaging significantly decreased.

Conclusion:

Children who receive RT for brain tumor, particularly if the circle of Willis region is involved, require close surveillance for the development of vasculopathy and consequent stroke. This surveillance must be even tighter if the patient has been treated with ventricular shunt for the possible synergistic interaction between the two causes on reducing cerebral perfusion and increasing the risk of acute ischemic events.

Review: Neurological Complications From Therapies for Pediatric Brain Tumors

Surgery, chemotherapy and radiation have been the mainstay of pediatric brain tumor treatment over the past decades. Recently, new treatment modalities have emerged for the management of pediatric brain tumors. These therapies range from novel radiotherapy techniques and targeted immunotherapies to checkpoint inhibitors and T cell transfer therapies. These treatments are currently investigated with the goal of improving survival and decreasing morbidity. However, compared to traditional therapies, these novel modalities are not as well elucidated and similarly has the potential to cause significant short and long-term sequelae, impacting quality of life. Treatment complications are commonly mediated through direct drug toxicity or vascular, infectious, or autoimmune mechanisms, ranging from immune effector cell associated neurotoxicity syndrome with CART-cells to neuropathy with checkpoint inhibitors. Addressing treatment-induced complications is the focus of new trials, specifically improving neurocognitive outcomes. The aim of this review is to explore the pathophysiology underlying treatment related neurologic side effects, highlight associated complications, and describe the future direction of brain tumor protocols. Increasing awareness of these neurologic complications from novel therapies underscores the need for quality-of-life metrics and considerations in clinical trials to decrease associated treatment-induced morbidity.

Glioblastoma with concomitant moyamoya vasculopathy in neurofibromatosis type 1: illustrative case

BACKGROUND

In a case of concurrent glioblastoma and moyamoya vasculopathy, it is arduous to safely perform surgery because the brain is highly vulnerable and collaterals are sometimes well developed. In addition, radiotherapy carries a risk of aggravating moyamoya vasculopathy, and chemotherapeutic agents also have a risk of interfering with collateral development.

OBSERVATIONS

A 48-year-old woman with neurofibromatosis type 1 was admitted because of left hemiparesis and hemispatial neglect. Brain imaging studies revealed a large mass with peripheral enhancement in the right frontal lobe and occlusion of the bilateral middle cerebral arteries with an abnormal vascular network at the base of the brain. Total tumor resection was performed, and the pathological diagnosis was isocitrate dehydrogenase-mutant glioblastoma. Radiotherapy with a total dose of 60 Gy was delivered with concurrent temozolomide, and thereafter six cycles of adjuvant temozolomide were given. Progression of moyamoya vasculopathy without symptoms was observed after the completion of each of radiotherapy and adjuvant temozolomide.

LESSONS

The authors present the first adult case of glioblastoma with moyamoya vasculopathy. Careful consideration and attention should be given throughout treatment to avoiding moyamoya vasculopathy-related ischemic and hemorrhagic events. Although the patient did not exhibit neurological deterioration, progression of moyamoya vasculopathy occurred early after radiotherapy and continued thereafter.

Delineation atlas of the Circle of Willis and the large intracranial arteries for evaluation of doses to neurovascular structures in pediatric brain tumor patients treated with radiation therapy

BACKGROUND

Survivors of pediatric brain tumors are susceptible to neurovascular disease after radiotherapy, with dose to the chiasm or Circle of Willis (CW) as risk factors. The aims of this study were to develop a delineation atlas of neurovascular structures, to investigate the doses to these structures in relation to tumor location and to investigate potential dose surrogates for the CW dose.

MATERIAL AND METHODS

An atlas of the CW, the large intracranial arteries and the suprasellar cistern (SC) was developed and validated. Thirty proton plans from previously treated pediatric brain tumor patients were retrieved and grouped according to tumor site: 10 central, 10 lateralized, and 10 posterior fossa tumors. Based on the atlas, neurovascular structures were delineated and dose metrics (mean dose (D_mean) and maximal dose (D_max)) to these structures and the already delineated chiasm were evaluated. The agreement between dose metrics to the CW vs. chiasm/SC was investigated. The minimal Hausdorff distance (HD_min) between the target and SC was correlated with the SC D_mean.

RESULTS

The median D_mean/D_max to the CW were 53 Gy(RBE)/55 Gy(RBE) in the central tumors, 18 Gy(RBE)/25 Gy(RBE) in the lateralized tumors and 30 Gy(RBE)/49 Gy(RBE) in the posterior fossa tumors. There was a good agreement between the D_max/D_mean to the CW and the SC for all cases (R²=0.99), while in the posterior fossa group, the CW D_max was underestimated when using the chiasm as surrogate (R²=0.76). Across all patients, cases with HD_min < 10 mm between the target and the SC received the highest SC D_mean.

CONCLUSION

The pattern of dose to neurovascular structures varied with the tumor location. For all locations, SC doses could be used as a surrogate for CW doses. A minimal distance larger than 10 mm between the target and the SC indicated a potential for neurovascular dose sparing.

A rare triad of morning glory disc anomaly, moyamoya vasculopathy, and transsphenoidal cephalocele: pathophysiological considerations and surgical management

Morning glory disc anomaly is a congenital abnormality of the optic disc and peripapillary retina reported as an isolated condition or associated with various anomalies, including basal encephaloceles and moyamoya vasculopathy. However, the co-occurrence of these three entities is extremely rare and the pathogenesis is still poorly understood. Moreover, data on the surgical management and long-term follow-up of the intracranial anomalies are scarce. Here, we describe the case of a 11-year-old boy with morning glory disc anomaly, transsphenoidal cephalocele, and moyamoya vasculopathy, who underwent bilateral indirect revascularization with encephalo-duro-myo-arterio-pericranio-synangiosis at the age of 2 years, and endoscopic repair of the transsphenoidal cephalocele at the age of 6 years. A rare missense variant (c.1081T>C,p.Tyr361His) was found in OFD1, a gene responsible for a X-linked ciliopathy, the oral-facial-digital syndrome type 1 (OFD1; OMIM 311200). This case expands the complex phenotype of OFD1 syndrome and suggests a possible involvement of OFD1 gene and Shh pathway in the pathogenesis of these anomalies.

Limits and pitfalls of indirect revascularization in moyamoya disease and syndrome

Moyamoya vasculopathy is a rare chronic cerebrovascular disorder characterized by the stenosis of the terminal branches of the internal carotid arteries and the proximal tracts of anterior and middle cerebral arteries. Although surgical revascularization does not significantly change the underlying pathogenic mechanisms, it plays a pivotal role in the management of affected individuals, allowing to decrease the risk of ischemic and hemorrhagic complications. Surgical approaches may be direct (extracranial-intracranial bypass), indirect, or a combination of the two. Several indirect techniques classifiable according to the tissue (muscle, periosteum, galea, dura mater, and extracranial tissues) or vessel (artery) used as a source of blood supply are currently available. In this study, we reviewed the pertinent literature and analyzed the advantages, disadvantages, and pitfalls of the most relevant indirect revascularization techniques. We discussed the technical aspects and the therapeutical implications of each procedure, providing a current state-of-the-art overview on the limits and pitfalls of indirect revascularization in the treatment of moyamoya vasculopathy.