Pediatric Primary Intracranial Malignant Melanoma: Case Report and Literature Review.

INTRODUCTION: Primary intracranial malignant melanoma (PIMM) is an extremely rare primary brain tumor with most cases diagnosed in adults. To date, there are only a few cases reported in the pediatric population. Owing to its infrequency, there are no established guidelines to treat this aggressive neoplasm. Recent insights suggest that PIMM are molecularly different between adults and children, whereby NRAS mutations drive tumor growth in the latter group. We present a unique case of PIMM in a pediatric patient and discuss the case in corroboration with current literature. CASE PRESENTATION: A previously well 15-year-old male presented with progressive symptoms of raised intracranial pressure. Neuroimaging reported a large solid-cystic lesion with significant mass effect. He underwent gross total resection of the lesion that was reported to be a PIMM with pathogenic single nucleotide variant NRAS p.Gln61Lys. Further workup for cutaneous, uveal, and visceral malignant melanoma was negative. A trial of whole-brain radiotherapy followed by dual immune checkpoint inhibitors was commenced. Despite concerted efforts, the patient had aggressive tumor progression and eventually demised from his disease. CONCLUSION: We therein report a case of pediatric PIMM, in the context of the patient's clinical, radiological, histopathological, and molecular findings. This case highlights the therapeutic difficulties faced in disease management and contributes to the very limited pool of medical literature for this devastating primary brain tumor.

Neuroblastoma patient-derived cultures are enriched for a mesenchymal gene signature and reflect individual drug response.

Ex vivo evaluation of personalized models can facilitate individualized treatment selection for patients, and advance the discovery of novel therapeutic options. However, for embryonal malignancies, representative primary cultures have been difficult to establish. We developed patient-derived cell cultures (PDCs) from chemo-naïve and post-treatment neuroblastoma tumors in a consistent and efficient manner, and characterized their in vitro growth dynamics, histomorphology, gene expression, and functional chemo-response. From 34 neuroblastoma tumors, 22 engrafted in vitro to generate 31 individual PDC lines, with higher engraftment seen with metastatic tumors. PDCs displayed characteristic immunohistochemical staining patterns of PHOX2B, TH, and GD2 synthase. Concordance of MYCN amplification, 1p and 11q deletion between PDCs and patient tumors was 83.3%, 72.7%, and 80.0% respectively. PDCs displayed a predominantly mesenchymal-type gene expression signature and showed upregulation of pro-angiogenic factors that were similarly enriched in culture medium and paired patient serum samples. When tested with standard-of-care cytotoxics at human Cmax -equivalent concentrations, MYCN-amplified and non-MYCN-amplified PDCs showed a differential response to cyclophosphamide and topotecan, which mirrored the corresponding patients' responses, and correlated with gene signatures of chemosensitivity. In this translational proof-of-concept study, early-phase neuroblastoma PDCs enriched for the mesenchymal cell subpopulation recapitulated the individual molecular and phenotypic profile of patient tumors, and highlighted their potential as a platform for individualized ex vivo drug-response testing.

Cerebrospinal fluid cytokines in metastatic group 3 and 4 medulloblastoma.

BACKGROUND: Metastatic medulloblastoma (MB) portends a poor prognosis. Amongst the 4 molecular subtypes, Group 3 and Group 4 patients have a higher incidence of metastatic disease, especially involving the neuroaxis. At present, mechanisms underlying MB metastasis remain elusive. Separately, inflammation has been implicated as a key player in tumour development and metastasis. Cytokines and their inflammation-related partners have been demonstrated to act on autocrine and, or paracrine pathways within the tumour microenvironment for various cancers. In this study, the authors explore the involvement of cerebrospinal fluid (CSF) cytokines in Group 3 and 4 MB patients with disseminated disease. METHODS: This is an ethics approved, retrospective study of prospectively collected data based at a single institution. Patient clinicpathological data and corresponding bio-materials are collected after informed consent. All CSF samples are interrogated using a proteomic array. Resultant expression data of selected cytokines are correlated with each individual's clinical information. Statistical analysis is employed to determine the significance of the expression of CSF cytokines in Group 3 and 4 patients with metastatic MB versus non-metastatic MB. RESULTS: A total of 10 patients are recruited for this study. Median age of the cohort is 6.6 years old. Based on Nanostring gene expression analysis, 5 patients have Group 3 as their molecular subtype and the remaining 5 are Group 4. There are 2 non-metastatic versus 3 metastatic patients within each molecular subtype. Proteomic CSF analysis of all patients for both subtypes show higher expression of CCL2 in the metastatic group versus the non-metastatic group. Within the Group 3 subtype, the MYC-amplified Group 3 MB patients with existing and delayed metastases express higher levels of CXCL1, IL6 and IL8 in their CSF specimens at initial presentation. Furthermore, a longitudinal study of metastatic Group 3 MB observes that selected cytokines are differentially expressed in MYC-amplified metastatic Group 3 MB, in comparison to the non-MYC amplified metastatic Group 3 MB patient. CONCLUSION: This study demonstrates higher expression of selected CSF cytokines, in particular CCL2, in metastatic Group 3 and 4 MB patients. Although our results are preliminary, they establish a proof-of-concept basis for continued work in a larger cohort of patients affected by this devastating disease.

Primary paediatric epidural sarcomas: molecular exploration of three cases.

BACKGROUND: Primary paediatric epidural sarcomas are extremely rare. Overall, there remains a paucity of knowledge in paediatric epidural sarcomas owing to the infrequent number of cases. The Archer FusionPlex Sarcoma Kit (ArcherDX, Inc) is a next-generation sequencing assay that has been reported to be a useful technique to detect recurrent fusion in sarcomas. We report the molecular exploration of 3 primary paediatric epidural sarcomas-one in the cranium (mesenchymal chondrosarcoma) and 2 in the spine (mesenchymal chondrosarcoma and Ewing sarcoma respectively). CASE PRESENTATION: This is a study approved by the hospital ethics board. Clinico-pathological information from 3 consenting patients with primary epidural sarcomas was collected. These selected tumours are interrogated via Archer FusionPlex Sarcoma Kit (ArcherDX, Inc) for genomic aberrations. Results were validated with RT-PCR and Sanger sequencing. All findings are corroborated and discussed in concordance with current literature. Our findings show 2 variants of the HEY1-NCOA2 gene fusion: HEY1 (exon 4)-NCOA2 (exon 13) and HEY1 (exon 4)-NCOA2 (exon 14), in both mesenchymal chondrosarcoma patients. Next, the Ewing sarcoma tumour is found to have EWSR1 (exon 10)-FLI1 (exon 8) translocation based on NGS. This result is not detected via conventional fluorescence in situ testing. CONCLUSIONS: This is a molecularly-centered study based on 3 unique primary paediatric epidural sarcomas. Our findings to add to the growing body of literature for these exceptionally rare and malignant neoplasms. The authors advocate global collaborative efforts and in-depth studies for targeted therapy to benefit affected children.

A germline variant of TP53 in paediatric diffuse leptomeningeal glioneuronal tumour.

PURPOSE: Diffuse leptomeningeal glioneuronal tumour (DLGNT) is an extremely rare tumour involving the neuroaxis. At present, its exact pathogenesis and associated factors remain incompletely characterised. Recent molecular investigations in a small cohort have offered some insights into this disease. However, the role of germline findings has not yet been fully explored in affected patients. The authors present a case of DLGNT, focusing on the clinical and molecular features with reference to current disease knowledge. METHODS: A 4-year-old male presented with raised intracranial pressure symptoms secondary to extensive leptomeningeal disease of the brain and spine. Preliminary impression was that of an inflammatory lesion. RESULTS: A lumbar biopsy of the lesion confirmed DLGNT on routine diagnostic examination. Further molecular analysis of his tumour and blood demonstrated a previously unreported TP53 exon 5 (c.147V > I) germline variant. Based on the latest DLGNT molecular subtyping classification, his tumour falls into the group with better clinical outcome. However, his germline findings may add an extra layer of uncertainty to his overall prognosis. CONCLUSION: Given that much remains unknown in many rare paediatric tumours at this stage, isolated findings found in an individual may be of significance. Supplementary genetic information, together with tumour molecular analysis, add to our current understanding of this uncommon disease. This case highlights the benefit of combined clinical and molecular efforts, including germline testing, especially for children affected by such challenging neoplasms.

The type II RAF inhibitor tovorafenib in relapsed/refractory pediatric low-grade glioma: the phase 2 FIREFLY-1 trial.

BRAF genomic alterations are the most common oncogenic drivers in pediatric low-grade glioma (pLGG). Arm 1 (n = 77) of the ongoing phase 2 FIREFLY-1 (PNOC026) trial investigated the efficacy of the oral, selective, central nervous system-penetrant, type II RAF inhibitor tovorafenib (420 mg m-2 once weekly; 600 mg maximum) in patients with BRAF-altered, relapsed/refractory pLGG. Arm 2 (n = 60) is an extension cohort, which provided treatment access for patients with RAF-altered pLGG after arm 1 closure. Based on independent review, according to Response Assessment in Neuro-Oncology High-Grade Glioma (RANO-HGG) criteria, the overall response rate (ORR) of 67% met the arm 1 prespecified primary endpoint; median duration of response (DOR) was 16.6 months; and median time to response (TTR) was 3.0 months (secondary endpoints). Other select arm 1 secondary endpoints included ORR, DOR and TTR as assessed by Response Assessment in Pediatric Neuro-Oncology Low-Grade Glioma (RAPNO) criteria and safety (assessed in all treated patients and the primary endpoint for arm 2, n = 137). The ORR according to RAPNO criteria (including minor responses) was 51%; median DOR was 13.8 months; and median TTR was 5.3 months. The most common treatment-related adverse events (TRAEs) were hair color changes (76%), elevated creatine phosphokinase (56%) and anemia (49%). Grade ≥3 TRAEs occurred in 42% of patients. Nine (7%) patients had TRAEs leading to discontinuation of tovorafenib. These data indicate that tovorafenib could be an effective therapy for BRAF-altered, relapsed/refractory pLGG. ClinicalTrials.gov registration: NCT04775485 .

Monomodality versus Combined Therapy in Optic Pathway Gliomas-20-Year Experience from a Singapore Children's Hospital.

Introduction: The treatment of pediatric optic pathway gliomas (OPG) is challenging. At present, most centers provide individualized treatment to maximize progression free survival (PFS) and minimize morbidity. We aim to report our experience in the management of pediatric OPG, and investigate factors associated with an increased duration of remission after treatment. Methods: This is a single-institution study approved by the hospital ethics board. A retrospective review of consecutive OPGs managed from 2000 to 2020 was performed. Patients were divided into those managed with monomodality treatment (MT) and those who received combined therapy (CT). MT included various forms of surgery, chemotherapy and radiotherapy given alone, while CT involves a combination of surgery and adjuvant chemotherapy and/or radiotherapy. Results: Twenty-two patients were selected for this study. They had 40 treatment cycles; and a total follow up duration of 194.8 patient-years. Most of them were male (63.6%) and presented with visual deficits (72.7%). The mean age at initial presentation was 65 months and majority (86.4%) had their tumors arising directly from the optic chiasm, with 77.3% with hypothalamic extension. One patient had Neurofibromatosis type I (4.5%). The most common histological diagnosis was pilocytic astrocytoma (90.9%), followed by pilomyxoid astrocytoma (9.1%). The 5- and 10- year PFS were 46.2% and 36.4% respectively, while the 5- and 10-year OS were both 100%. When accounting for treatment type, there were 24 treatment cycles with MT (60.0%) and 16 CT (40.0%). After adjustment, treatments with MT were shown to have a shorter mean duration of remission (MT: 45 ± 49, CT: 84 ± 79 months; p = 0.007). Cox regression curve plotted after adjusting for patient's age at treatment demonstrated a significantly longer PFS in the CT group (p = 0.037). Conclusions: Our results suggest a significant survival benefit of CT over MT for affected patients due to the prolonged the duration of disease remission, for both primary and subsequent treatments. Nonetheless, we acknowledge that our study reflects the outcomes of treatment strategies that have evolved over time. We emphasize the need for collective efforts from a dedicated multidisciplinary team and international collaborations for better disease understanding.

Integrated Genomic Profiling and Drug Screening of Patient-Derived Cultures Identifies Individualized Copy Number-Dependent Susceptibilities Involving PI3K Pathway and 17q Genes in Neuroblastoma.

Neuroblastoma is the commonest extracranial pediatric malignancy. With few recurrent single nucleotide variations (SNVs), mutation-based precision oncology approaches have limited utility, but its frequent and heterogenous copy number variations (CNVs) could represent genomic dependencies that may be exploited for personalized therapy. Patient-derived cell culture (PDC) models can facilitate rapid testing of multiple agents to determine such individualized drug-responses. Thus, to study the relationship between individual genomic aberrations and therapeutic susceptibilities, we integrated comprehensive genomic profiling of neuroblastoma tumors with drug screening of corresponding PDCs against 418 targeted inhibitors. We quantified the strength of association between copy number and cytotoxicity, and validated significantly correlated gene-drug pairs in public data and using machine learning models. Somatic mutations were infrequent (3.1 per case), but copy number losses in 1p (31%) and 11q (38%), and gains in 17q (69%) were prevalent. Critically, in-vitro cytotoxicity significantly correlated only with CNVs, but not SNVs. Among 1278 significantly correlated gene-drug pairs, copy number of GNA13 and DNA damage response genes CBL, DNMT3A, and PPM1D were most significantly correlated with cytotoxicity; the drugs most commonly associated with these genes were PI3K/mTOR inhibitor PIK-75, and CDK inhibitors P276-00, SNS-032, AT7519, flavopiridol and dinaciclib. Predictive Markov random field models constructed from CNVs alone recapitulated the true z-score-weighted associations, with the strongest gene-drug functional interactions in subnetworks involving PI3K and JAK-STAT pathways. Together, our data defined individualized dose-dependent relationships between copy number gains of PI3K and STAT family genes particularly on 17q and susceptibility to PI3K and cell cycle agents in neuroblastoma. Integration of genomic profiling and drug screening of patient-derived models of neuroblastoma can quantitatively define copy number-dependent sensitivities to targeted inhibitors, which can guide personalized therapy for such mutationally quiet cancers.

Right middle cerebral artery infarct after minor head trauma in an infant: Case report and literature review.

Ishaemic stroke (IS) in the paediatric population is extremely rare. In this age group, the occurrence of IS often concurs with underlying congenital heart disease, haematological, metabolic or immunological conditions. In contrast, the association between IS and minor head injury in children has been sparse in current literature. The authors report a case of a healthy 9-month-old male who was found to have a right middle cerebral artery territory infarct after a minor head injury. An extensive medical workup was performed, and it was negative for any previously undiagnosed co-morbidities. Given the paucity of such cases, the condition and its management are discussed in corroboration with current literature.

Hearing Loss in Newborns with Cleft Lip and/or Palate.

INTRODUCTION: This study aims to review the results of hearing screens in newborns with cleft deformities. MATERIALS AND METHODS: A retrospective audit of 123 newborns with cleft deformities, born between 1 April 2002 and 1 December 2008, was conducted. Data on the results of universal newborn hearing screens (UNHS) and high-risk hearing screens, age at diagnosis, severity/type of hearing loss and mode of intervention were obtained from a prospectively maintained hearing database. RESULTS: Thirty-one of 123 newborns (25.2%) failed the first automated auditory brainstem response (AABR). Seventy percent of infants (56 out of 80) who passed the UNHS failed the high-risk hearing screens which was conducted at 3 to 6 months of age. Otolaryngology referral rate was 67.5% (83/123); 90.3% of 31 newborns who failed the first AABR eventually required otolaryngology referrals. Incidence of hearing loss was 24.4% (30/123; 25 conductive, 2 mixed and 3 sensorineural), significantly higher than the hospital incidence of 0.3% (OR: 124.9, 95% CI, 81.1 to 192.4, P <0.01). In terms of severity, 8 were mild, 15 moderate, 5 severe, 2 profound. Eighteen out of 30 infants (60%) were detected from the high-risk hearing screens after passing the first AABR. CONCLUSION: These newborns had a higher risk of failing the UNHS and high-risk hearing screen. There was a higher incidence of hearing loss which was mainly conductive. Failure of the first AABR was an accurate predictor of an eventual otolaryngology referral, suggesting that a second AABR may be unnecessary. High-risk hearing screens helped to identify hearing loss which might have been missed out early on in life or which might have evolved later in infancy.