Pediatric Neuro-oncology

OBJECTIVE

This article reviews the most common pediatric brain tumors, neurocutaneous syndromes, treatment-related neurotoxicities, and the long-term outcomes of survivors.

LATEST DEVELOPMENTS

In the era of molecular diagnostics, the classification, management, and prognostication of pediatric brain tumors and neurocutaneous syndromes has been refined, resulting in advancements in patient management. Molecular diagnostics have been incorporated into the most recent World Health Organization 2021 classification. This knowledge has allowed for novel therapeutic approaches targeting the biology of these tumors with the intent to improve overall survival, decrease treatment-related morbidity, and improve quality of life. Advances in management have led to better survival, but mortality remains high and significant morbidity persists. Current clinical trials focus on tumor biology targeted therapy, deescalation of therapy, and multimodal intensified approaches with targeted therapy in more high-risk tumors.

ESSENTIAL POINTS

Molecular diagnostics for pediatric brain tumors and neurocutaneous syndromes have led to novel therapeutic approaches targeting the biology of these tumors with the goals of improving overall survival and decreasing treatment-related morbidity. Further understanding will lead to continued refinement and improvement of tumor classification, management, and prognostication.

PHACE syndrome: not always 'tilting telephones' and Dandy-Walker malformations…

Linked article: This Editorial comments on Pomar et al. Click here to view the article.

Neurofibromatosis type1, type 2, tuberous sclerosis and Von Hippel-Lindau disease

Neurocutaneous syndromes (also known as phakomatoses) are heterogenous group of disorders that involve derivatives of the neuroectoderm. Each disease has diagnostic and pathognomonic criteria, once identified, thorough clinical examination to the patient and the family members should be done. Magnetic resonance imaging (MRI) is used to study the pathognomonic findings withing the CNS (Evans et al. in Am J Med Genet A 152A:327-332, 2010). This chapter includes the 4 most common syndromes faced by neurosurgeons and neurologists; neurofibromatosis types 1 and 2, tuberous sclerosis and Von Hippel-Lindau disease. Each syndrome has specific genetic anomaly that involves a tumor suppressor gene and the loss of inhibition of specific pathways. The result is a spectrum of cutaneous manifestations and neoplasms.

Isolated retinal astrocytic hamartoma with 7-year follow-up: A case report

RATIONALE

Retinal astrocytic hamartoma (RAH) is a rare benign tumor originating from astrocytic cells located in the neural cell layer of the retina. It is commonly seen in patients with phakomatoses such as tuberous sclerosis complex or neurofibromatosis, rarely as an isolated retinal mass. This lesion is usually asymptomatic; however, these located in the area of the optic nerve, macula, or exhibiting the features of exudation, neovascularization may present visual disturbances and decreased visual acuity.

PATIENT CONCERNS

We present a rare case of a 15-year-old boy, with no significant past medical history, whose cause of visual disturbances turned out to be isolated RAH.

DIAGNOSES

Based on the results of color images of the fundus, fluorescein angiography as well as the analysis of magnetic resonance imaging, the patient was diagnosed with RAH.

INTERVENTIONS

Additionally an B-scan ultrasonography, static and kinetic perimetry were performed.

OUTCOMES

Fundoscopic examination showed a unilateral yellowish, well-circumscribed, mulberry-like lesion with a wide base, located in inferosnasal quadrant, in the vinicity of the optic nerve. The patient underwent neurological, pediatric, and genetic evaluations that excluded other pathological findings or underlying systemic disease.

LESSONS

The prognosis for RAH is generally good, however, the lesion requires regular ophthalmologic follow-up to rule out the progression of the tumor mass. The patient 7-year follow-up history is without evidence of tumor growth, local or general deterioration of the condition.

[Cosmetic and functional results after resection of cutaneous neurofibroma in neurofibromatosis type 1 : Operation of neurofibroma improves quality of life while having moderate complications]

BACKGROUND

Neurofibromatosis type 1, also known as Recklinghausen's disease, is a neurocutaneous tumor syndrome that is genetically determined and is associated with infestation of the integument with neurofibromas (nerve sheath tumors). The occurrence of neurofibromas can be very stressful for patients and often contributes to a reduced quality of life for patients, especially if externally visible body parts are affected. The aim of this study is to show to what extent the resection of cutaneous neurofibromas can improve patients' quality of life.

MATERIALS AND METHODS

For this study, we conducted a retrospective data collection via questionnaire on the quality of life before and after the surgical removal of cutaneous neurofibromas at the Department of Dermatology, University Hospital of Tübingen. An adapted dermatological quality of life index and a postoperative questionnaire on patient satisfaction were used. In addition, patient data were taken from doctor's notes, surgical reports, and outpatient documentation. A total of 30 patients with neurofibromatosis type 1 who underwent inpatient or outpatient surgery for cutaneous neurofibromas at the Tübingen dermatology hospital between 2016 and 2020 were surveyed. The survey results were statistically analyzed and represented as absolute and relative frequencies.

RESULTS

Our study indicates an improved quality of life after surgery for cutaneous neurofibromas, especially regarding limitations in everyday life, self-consciousness, the choice of clothing, and leisure activities. The majority of our patients showed no new occurrence of neurofibromas in the surgical area and postoperative bleeding or wound infections were rare.

CONCLUSION

In relation to the high level of satisfaction with the surgical and cosmetic results and also the positive influence on quality of life, our study indicates a favorable risk-benefit ratio for the resection of cutaneous neurofibromas in neurofibromatosis I.

Selenium Status in Paediatric Patients with Neurodevelopmental Diseases

Neurodevelopmental diseases are often associated with other comorbidities, especially inflammatory processes. The disease may affect the trace element (TE) status, which in turn may affect disease severity and progression. Selenium (Se) is an essential TE required for the biosynthesis of selenoproteins including the transporter selenoprotein P (SELENOP) and extracellular glutathione peroxidase (GPX3). SELENOP deficiency in transgenic mice resulted in a Se status-dependent phenotype characterized by impaired growth and disturbed neuronal development, with epileptic seizures on a Se-deficient diet. Therefore, we hypothesized that Se and SELENOP deficiencies may be prevalent in paediatric patients with a neurodevelopmental disease. In an exploratory cross-sectional study, serum samples from children with neurodevelopmental diseases (n = 147) were analysed for total serum Se, copper (Cu), and zinc (Zn) concentrations as well as for the TE biomarkers SELENOP, ceruloplasmin (CP), and GPX3 activity. Children with epilepsy displayed elevated Cu and Zn concentrations but no dysregulation of serum Se status. Significantly reduced SELENOP concentrations were found in association with intellectual disability (mean ± SD (standard deviation); 3.9 ± 0.9 mg/L vs. 4.4 ± 1.2 mg/L, p = 0.015). A particularly low GPX3 activity (mean ± SD; 172.4 ± 36.5 vs. 192.6 ± 46.8 U/L, p = 0.012) was observed in phacomatoses. Autoantibodies to SELENOP, known to impair Se transport, were not detected in any of the children. In conclusion, there was no general association between Se deficiency and epilepsy in this observational analysis, which does not exclude its relevance to individual cases. Sufficiently high SELENOP concentrations seem to be of relevance to the support of normal mental development. Decreased GPX3 activity in phacomatoses may be relevant to the characteristic skin lesions and merits further analysis. Longitudinal studies are needed to determine whether the observed differences are relevant to disease progression and whether correcting a diagnosed TE deficiency may confer health benefits to affected children.

Identification of Codon 146 KRAS Variants in Isolated Epidermal Nevus and Multiple Lesions in Oculoectodermal Syndrome: Confirmation of the Phenotypic Continuum of Mosaic RASopathies

Mosaic RASopathies are a molecularly heterogeneous group of (neuro)cutaneous syndromes with high phenotypical variability. Postzygotic variants in KRAS have been described in oculoectodermal syndrome (OES), encephalocraniocutaneous lipomatosis (ECCL) and epidermal nevus syndrome (ENS). This study confirms the continuum of mosaic neurocutaneous RASopathies showing codon 146 KRAS variants in an individual with OES and, for the first time, in an individual with (isolated) epidermal nevus. The presence of a nevus psiloliparus in individuals with OES indicates that this finding is not specific for ECCL and highlights the phenotypical overlap between ECCL and OES. The presence of the somatic KRAS variant in the nevus psiloliparus resolves the underlying molecular etiology of this fatty-tissue nevus. In addition, this finding refutes the theory of non-allelic twin-spotting as an underlying hypothesis to explain the concurrent presence of two different mosaicisms in one individual. The identification of codon 146 KRAS variants in isolated epidermal nevus introduces a new hot spot for this condition, which is useful for increasing molecular genetic testing using targeted gene sequencing panels.

Rare diagnosis of Melkersson-Rosenthal syndrome in a paediatric patient

Melkersson-Rosenthal syndrome (MRS) is a rare neurocutaneous syndrome characterised by the triad of recurrent orofacial swelling, facial nerve palsy and fissured tongue. This diagnosis is particularly rare in children. We aim to increase awareness of the syndromic association of these clinical features since most patients present with a monosymptomatic form, reiterating the importance of detailed history and thorough physical examination, for the timely identification of these patients. Not only the recurring of symptoms, but also the association of MRS with other medical conditions, make 'earlier' diagnosis of the Syndrome beneficial. The average delay in diagnosis is 4-9 years. Although most cases resolve without treatment, when treated,steroids are most commonly used. Variable options have been tried for refractory and frequently recurrent cases. We present a case of MRS in a 12-year-old girl, diagnosed 3 years after onset of symptoms. We reviewed updated literature for MRS and associated clinical conditions as well as published treatment options.

[Parry-Romberg, a neurocutaneous syndrome: presentation of three cases]

BACKGROUND

Parry-Romberg syndrome is characterized by progressive hemiatrophy of the skin, subcutaneous tissue, muscle and bones of the skull. Its incidence is low, with a progressive and slow course. Its etiology is unknown, but it has been associated with several factors. Its clinical presentation involves dermatological, musculoskeletal and neuropsychiatric manifestations. The treatment consists of medical and surgical strategies. The use of steroids, alone or in combination with immunomodulators, has the objective of slowing down progression. The surgical treatment lies in facial reconstruction or volumetric regeneration, to correct the appearance and function of facial structures. The objective is to show three cases of Parry-Romberg syndrome with the representative characteristics of the disease.

CLINICAL CASES

1) A 41-year-old woman with atrophy and right supraciliary hypochromia associated with seizures and headache. 2) A 43-year-old woman with parietal deformation and right supraciliary atrophy, associated with facial paralysis, depression and headache. 3) A 36-year-old woman with right hemifacial atrophy associated with ocular involvement and headache. The indicated treatment was based on a systemic steroid plus a cytostatic agent. The surgical treatment was evaluated according to the affection of facial structures.

CONCLUSIONS

Parry-Romberg syndrome is a rare disease, characterized by progressive atrophy. Clinical manifestations determine the diagnosis and early start of medical and surgical treatment.

Neurofibromatosis Type 1: Review and Update on Emerging Therapies

Neurofibromatosis type 1 is an autosomal dominant neurocutaneous disorder affecting 1 in 3000 births. This familial tumor predisposition syndrome is diagnosed clinically and affects the skin, bones, and nervous system. Malignant tumors can arise in childhood or adulthood and are the most common cause of mortality in this population. Early diagnosis and management led by a multidisciplinary team remains the standard of care, particularly in the management of optic pathway glioma. Emerging concepts in the genetic patterns of this condition have led to the introduction of new treatment modalities that target the mitogen-activated protein kinase and the mammalian target of rapamycin pathways. In this review, the role of the ophthalmologist and approach to screening for optic pathway glioma are outlined based on previous recommendations. Updates on choroidal involvement, as a diagnostic criterion, will also be discussed, further highlighting the pivotal role of the ophthalmologist in the diagnosis and management of this complex condition.

Neurocutaneous Disorders

PURPOSE OF REVIEW

This article presents an up-to-date summary of the genetic etiology, diagnostic criteria, clinical features, and current management recommendations for the most common neurocutaneous disorders encountered in clinical adult and pediatric neurology practices.

RECENT FINDINGS

The phakomatoses are a phenotypically and genetically diverse group of multisystem disorders that primarily affect the skin and central nervous system. A greater understanding of the genetic and biological underpinnings of numerous neurocutaneous disorders has led to better clinical characterization, more refined diagnostic criteria, and improved treatments in neurofibromatosis type 1, Legius syndrome, neurofibromatosis type 2, Noonan syndrome with multiple lentigines, tuberous sclerosis complex, Sturge-Weber syndrome, and incontinentia pigmenti.

SUMMARY

Neurologists require a basic knowledge of and familiarity with a wide variety of neurocutaneous disorders because of the frequent involvement of the central and peripheral nervous systems. A simple routine skin examination can often open a broad differential diagnosis and lead to improved patient care.

Covalent Surface Modification of Gallium Arsenide Photocathodes for Water Splitting in Highly Acidic Electrolyte

Efficient water splitting using light as the only energy input requires stable semiconductor electrodes with favorable energetics for the water-oxidation and proton-reduction reactions. Strategies to tune electrode potentials using molecular dipoles adsorbed to the semiconductor surface have been pursued for decades but are often based on weak interactions and quickly react to desorb the molecule under conditions relevant to sustained photoelectrolysis. Here, we show that covalent attachment of fluorinated, aromatic molecules to p-GaAs(1 0 0) surfaces can be employed to tune the photocurrent onset potentials of p-GaAs(1 0 0) photocathodes and reduce the external energy required for water splitting. Results indicate that initial photocurrent onset potentials can be shifted by nearly 150 mV in pH -0.5 electrolyte under 1 Sun (1000 W m^-2 ) illumination resulting from the covalently bound surface dipole. Though X-ray photoelectron spectroscopy analysis reveals that the covalent molecular dipole attachment is not robust under extended 50 h photoelectrolysis, the modified surface delays arsenic oxide formation that results in a p-GaAs(1 0 0) photoelectrode operating at a sustained photocurrent density of -20.5 mA cm^-2 within -0.5 V of the reversible hydrogen electrode.

Encephalocraniocutaneous lipomatosis, a rare neurocutaneous disorder: report of additional three cases

PURPOSE

Encephalocraniocutaneous lipomatosis (ECCL) is a rare congenital neurocutaneous disorder. It was described by Haberland in 1970 and is also called Haberland syndrome. It is characterized by unilateral skin lesions such as lipomas, connective tissue nevi, and alopecia with ipsilateral ophthalmological and cerebral malformations with or without psychomotor and mental retardation and early-onset seizure.

METHODS

We present three pediatric cases (two boys, one girl) with ECCL. All the patients' sociodemographic, clinical, and neuroradiological data was collected.

RESULTS

We describe two male (5 and 1.3 years old) and one female (15 years old) cases. All patients have unilateral left-sided alopecia with ipsilateral ocular lesion and the cerebral lesion. All patients were born at term; their past history and family histories were unremarkable. Their electroencephalograms showed hemispheric asymmetry. All of the cases had right-sided mild to moderate hemiparesis. In addition, our second case is having optic glioma and this case is the fifth case with glioma associated with ECCL.

CONCLUSIONS

We describe three additional cases with ECCL which is an extremely rare neurocutaneous syndrome. Also, case 2 has optic glioma and according to the literature this is the fifth case of low-grade gliomas with ECCL. We suggest that patients who have ocular lesion and ipsilateral skin lesion must be examined for ECCL, and the patients must be followed up with cerebral MRI once a year for low-grade gliomas.

Mutations in the glycosylphosphatidylinositol gene PIGL cause CHIME syndrome

CHIME syndrome is characterized by colobomas, heart defects, ichthyosiform dermatosis, mental retardation (intellectual disability), and ear anomalies, including conductive hearing loss. Whole-exome sequencing on five previously reported cases identified PIGL, the de-N-acetylase required for glycosylphosphatidylinositol (GPI) anchor formation, as a strong candidate. Furthermore, cell lines derived from these cases had significantly reduced levels of the two GPI anchor markers, CD59 and a GPI-binding toxin, aerolysin (FLAER), confirming the pathogenicity of the mutations.

The group of epidermal nevus syndromes Part I. Well defined phenotypes

The epidermal nevus syndromes represent a group of distinct disorders that can be distinguished by the type of associated epidermal nevus and by the criterion of presence or absence of heritability. Well defined syndromes characterized by organoid epidermal nevi include Schimmelpenning syndrome, phacomatosis pigmentokeratotica, nevus comedonicus syndrome, angora hair nevus syndrome, and Becker nevus syndrome. The molecular basis of these disorders has so far not been identified. By contrast, the group of syndromes characterized by keratinocytic nevi comprises three phenotypes with a known molecular etiology in the form of CHILD (congenital hemidysplasia with ichthyosiform nevus and limb defects) syndrome, type 2 segmental Cowden disease, and fibroblast growth factor receptor 3 epidermal nevus syndrome (García-Hafner-Happle syndrome), whereas Proteus syndrome is still of unknown origin. From this overview, it is clear that a specific type of these disorders cannot be classified by the name "epidermal nevus syndrome" nor by the terms "organoid nevus syndrome" or "keratinocytic nevus syndrome."

LEARNING OBJECTIVES

After completing this learning activity, participants should be able to distinguish nine different epidermal nevus syndromes by their characteristic features, understand the practical significance of avoiding terms like "epidermal nevus syndrome" or "keratinocytic nevus syndrome" to define any specific entity within this group of disorders, and differentiate between nonhereditary traits and those bearing a genetic risk because of either Mendelian or non-Mendelian inheritance.

Isoprenylated proteins

Isoprenoids are synthesized in all living organisms and are incorporated into diverse classes of end-products that participate in a multitude of cellular processes relating to cell growth, differentiation, cytoskeletal function and vesicle trafficking. In humans, the non-sterol isoprenoids, farnesyl pyrophosphate and geranylgeranyl-pyrophosphate, are synthesized via the mevalonate pathway and are covalently added to members of the small G protein superfamily. Isoprenylated proteins have key roles in membrane attachment and protein functionality, have been shown to have a central role in some cancers and are likely also to be involved in the pathogenesis and progression of atherosclerosis and Alzheimer disease. This review details current knowledge on the biosynthesis of isoprenoids, their incorporation into proteins by the process known as prenylation and the complex regulatory network that controls these proteins. An improved understanding of these processes is likely to lead to the development of novel therapies that will have important implications for human health and disease.

Perioperative management of infants with the linear naevus sebaceous syndrome of Jadassohn: a report of two cases

Neurofibromatosis and tuberous sclerosis are the most well-recognized of the congential phakomatoses, a group of six hereditary neuro-oculo-cutaneous disorders. Although easily diagnosed at birth by a parasagittal line of facial sebaceous naevi, the linear naevus sebaceous syndrome (LNSS) of Jadassohn is the rarest phakomatosis, one often characterized by airway and anaesthetic considerations that do not apply to the other phakomatoses. In addition to its obvious cutaneous manifestations, LNSS is characterized by hemifacial asymmetry, an anatomic predictor of difficult trachael intubation, and intractable seizure activity, a condition that limits selection of anaesthetics. The perioperative management challenges of LNSS are depicted in the presentation of two cases of LNSS with different outcomes and contrasted with the major anaesthetic considerations in the perioperative management of other, more common phakomatoses.