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We describe a 46,XX girl with Denys-Drash syndrome (DDS), showing both kidney disease and genital abnormalities, in whom a misdiagnosis of hyperandrogenism was made. A 15 year-old girl was affected by neonatal nephrotic syndrome, progressing to end stage kidney failure. Hair loss and voice deepening were noted during puberty. Pelvic ultrasound and MRI showed utero-tubaric agenesis, vaginal atresia and urogenital sinus, with inguinal gonads. Gonadotrophin and estradiol levels were normal, but testosterone levels increased up to 285 ng/dL at Tanner stage 3. She underwent prophylactic gonadectomy and histopathology reported fibrotic ovarian cortex containing numerous follicles in different maturation stages and rudimental remnants of Fallopian tubes. No features of gonadoblastoma were detected. Unexpectedly, testosterone levels were found elevated 4 months after gonadectomy (157 ng/dL). Recent medical history revealed a chronic assumption of a high daily dose of biotin, as a therapeutic support for hair loss. Laboratory immunoassay instruments used streptavidin-biotin interaction to detect hormones and, in competitive immunoassays, high concentrations of biotin can result in false high results. Total testosterone, measured using liquid chromatography tandem mass spectrometry (LC-MS/MS), was found within reference intervals. Similar testosterone levels were detected repeating the immunoassay two weeks after biotin uptake interruption. Discordance between clinical presentation and biochemical results in patients taking biotin, should rise the suspicion of erroneous results. Improved communication among patients, health care providers, and laboratory professionals is required concerning the likelihood of biotin interference with immunoassays.

Purpose: To develop a predictive grading model based on diffusion kurtosis imaging (DKI) metrics in children affected by gliomas, and to investigate the clinical impact of the predictive model by correlating with overall survival and progression-free survival. Materials and methods: 59 patients with a histological diagnosis of glioma were retrospectively studied (33 M, 26 F, median age 7.2 years). Patients were studied on a 3T scanner with a standardized MR protocol, including conventional and DKI sequences. Mean kurtosis (MK), axial kurtosis (AK), radial kurtosis (RK), fractional anisotropy (FA), and apparent diffusion coefficient (ADC) maps were obtained. Whole tumour volumes (VOIs) were segmented semi-automatically. Mean DKI values were calculated for each metric. The quantitative values from DKI-derived metrics were used to develop a predictive grading model to develop a probability prediction of a high-grade glioma (pHGG). Three models were tested: DTI-based, DKI-based, and combined (DTI and DKI). The grading accuracy of the resulting probabilities was tested with a receiver operating characteristics (ROC) analysis for each model. In order to account for dataset imbalances between pLGG and pHGG, we applied a random synthetic minority oversampling technique (SMOTE) analysis. Lastly, the most accurate model predictions were correlated with progression-free survival (PFS) and overall survival (OS) using the Kaplan–Meier method. Results: The cohort included 46 patients with pLGG and 13 patients with pHGG. The developed model predictions yielded an AUC of 0.859 (95%CI: 0.752–0.966) for the DTI model, of 0.939 (95%CI: 0.879–1) for the DKI model, and of 0.946 (95%CI: 0.890–1) for the combined model, including input from both DTI and DKI metrics, which resulted in the most accurate model. Sample estimation with the random SMOTE analysis yielded an AUC of 0.98 on the testing set. Model predictions from the combined model were significantly correlated with PFS (25.2 months for pHGG vs. 40.0 months for pLGG, p < 0.001) and OS (28.9 months for pHGG vs. 44.9 months for pLGG, p < 0.001). Conclusions: a DKI-based predictive model was highly accurate for pediatric glioma grading. The combined model, derived from both DTI and DKI metrics, proved that DKI-based model predictions of tumour grade were significantly correlated with progression-free survival and overall survival.

Infant high-grade gliomas appear clinically distinct from their counterparts in older children, indicating that histopathologic grading may not accurately reflect the biology of these tumors. We have collected 241 cases under 4 years of age, and carried out histologic review, methylation profiling, and custom panel, genome, or exome sequencing. After excluding tumors representing other established entities or subgroups, we identified 130 cases to be part of an “intrinsic” spectrum of disease specific to the infant population. These included those with targetable MAPK alterations, and a large proportion of remaining cases harboring gene fusions targeting ALK (n = 31), NTRK1/2/3 (n = 21), ROS1 (n = 9), and MET (n = 4) as their driving alterations, with evidence of efficacy of targeted agents in the clinic. These data strongly support the concept that infant gliomas require a change in diagnostic practice and management. Significance: Infant high-grade gliomas in the cerebral hemispheres comprise novel subgroups, with a prevalence of ALK, NTRK1/2/3, ROS1, or MET gene fusions. Kinase fusion–positive tumors have better outcome and respond to targeted therapy clinically. Other subgroups have poor outcome, with fusion-negative cases possibly representing an epigenetically driven pluripotent stem cell phenotype. See related video: https://vimeo.com/438254885 See related commentary by Szulzewsky and Cimino, p. 904. This article is highlighted in the In This Issue feature, p. 890

As a relevant element of novelty, the fifth CNS WHO Classification highlights the distinctive pathobiology underlying gliomas arising primarily in children by recognizing for the first time the families of paediatric-type diffuse gliomas, both high-grade and low-grade. This review will focus on the family of paediatric-type diffuse high-grade gliomas, which includes four tumour types: 1) Diffuse midline glioma H3 K27-altered; 2) Diffuse hemispheric glioma H3 G34-mutant; 3) Diffuse paediatric-type high-grade glioma H3-wildtype and IDH-wildtype; and 4) Infant-type hemispheric glioma. The essential and desirable diagnostic criteria as well as the entities entering in the differential will be discussed for each tumour type. A special focus will be given on the issues encountered in the daily practice, especially regarding the diagnosis of the diffuse paediatric-type high-grade glioma H3-wildtype and IDH-wildtype. The advantages and the limits of the multiple molecular tests which may be utilised to define the entities of this tumour family will be evaluated in each diagnostic context.

Purpose: Testicular germ cell tumors are the fourth most common neoplasm in adolescents, accounting for 8% of all tumors in the age group 15–19 years. On rare instances, the primary testicular lesion is not clinically or radiologically evident while nodal or visceral metastases represent the clinical manifestations of the disease. This phenomenon is described as “burned-out testicular tumor.” In this paper, the authors report a single-institution experience with burned-out testicular tumors in adolescents and discuss their clinical implications.Patients and Methods: All the patients diagnosed with metastatic testicular germ cell tumors at Bambino Gesù Children Hospital between January 1, 2010, and June 30, 2020, were included in the study. Patients were categorized into two groups: “primary testicular” and “burned out.” All the patients were staged and treated according to the AIEOP–TCGM 2004 protocol.Results: Eleven patients were classified as “primary testicular,” and five patients were classified as “burned out.” “Burned-out” tumors were associated with the presence of systemic symptoms compared to “primary testicular” tumors (80 vs. 0%; p = 0.0027) and higher aFP, hCG, and LDH levels (p < 0.00001). The “burned-out” population had a statistically significant higher incidence of relevant toxicity than the “primary testicular” population (80 vs. 18%; p = 0.0357) and a worse outcome in terms of both mean overall survival (15 vs. 43 months; p = 0.0299) and mean event-free survival (12 vs. 38 months; p = 0.0164).Conclusion: “Burned-out” testicular tumors seem to be a well-distinct clinical entity with a high treatment-related toxicity and poor prognosis. Further studies are needed to clarify the “burned-out phenomenon” and to identify more effective therapeutic strategies for these patients.

The rare nevus sebaceous (NS) syndrome (NSS) includes cortical malformations and drug-resistant epilepsy. Somatic RAS-pathway genetic variants are pathogenetic in NS, but not yet described within the brain of patients with NSS. We report on a 5-year-old boy with mild psychomotor delay. A brown-yellow linear skin lesion suggestive of NS in the left temporo-occipital area was evident at birth. Epileptic spasms presented at aged six months. EEG showed continuous left temporo-occipital epileptiform abnormalities. Brain MRI revealed a similarly located diffuse cortical malformation with temporal pole volume reduction and a small hippocampus. We performed a left temporo-occipital resection with histopathological diagnosis of focal cortical dysplasia type Ia in the occipital region and hippocampal sclerosis type 1. Three years after surgery, he is seizure-and drug-free (Engel class Ia) and showed cognitive improvement. Genetic examination of brain and skin specimens revealed the c.35G > T (p.Gly12Val) KRAS somatic missense mutation. Literature review suggests epilepsy surgery in patients with NSS is highly efficacious, with 73% probability of seizure freedom. The few histological analyses reported evidenced disorganized cortex, occasionally with cytomegalic neurons. This is the first reported association of a KRAS genetic variant with cortical malformations associated with epilepsy, and suggests a possible genetic substrate for hippocampal sclerosis.

Von Hippel–Lindau (VHL) disease is a heritable cancer syndrome in which benign and malignant tumors and/or cysts develop throughout the central nervous system (CNS) and visceral organs. The disease results from mutations in the VHL tumor suppressor gene located on chromosome 3 (3p25-26). A majority of individuals (60–80%) with VHL disease will develop CNS hemangioblastomas (HMG). Endolymphatic sac tumor (ELST) is an uncommon, locally aggressive tumor located in the medial and posterior petrosal bone region. Its diagnosis is based on clinical, radiological, and pathological correlation, and it can occur in the setting of VHL in up to 10–15% of individuals. We describe a 17-year-old male who presented with a chief complaint of hearing loss. Brain and spine Magnetic Resonance Imaging documented the presence of an expansive lesion in the left cerebellar hemisphere, compatible with HMG in association with a second cerebellopontine lesion compatible with ELST. The peculiarity of the reported case is due to the simultaneous presence of two typical characteristics of VHL, which led to performing comprehensive genetic testing, thus allowing for the diagnosis of VHL. Furthermore, ELST is rare before the fourth decade of life. Early detection of these tumors plays a key role in the optimal management of this condition.

Purpose Our purpose was to better understand the pathogenesis of seizures associated with angiocentric glioma. Angiocentric glioma is an indolent and rare low-grade glioma. Its typical clinical presentation is with epileptic seizures. The pathogenesis of tumor-associated seizures is poorly understood. Among the possible pathomechanisms, the increased neurotoxic concentrations of the glutamate has been proposed. Glutamate transporters, pyruvate carboxylase and glutamine synthetase are involved in maintaining the physiological concentration of glutamate in the inter synaptic spaces. Methods We evaluated the immunohistochemical expression of EAAT2 (the most important glutamate transporter), pyruvate carboxylase and glutamine synthetase in 17 angiocentric gliomas. Results EAAT2 was never expressed (0%) in the neoplastic cells in none of the cases studied. Pyruvate carboxylase was expressed in the cytoplasm of the neoplastic cells in 16/17 cases (94 %). Glutamine synthetase was expressed in the cytoplasm of the neoplastic cells in 15/17 cases (88 %). Conclusion The net result of this enzymatic expression, in particular considering the loss of EAAT2, could be an increased glutamate concentration in the synaptic clef, which might increase local network excitability initially involving intratumoral neurons. The observation that the angiocentric glioma-associated epilepsy might be at least in part related to EAAT2 deficiency opens up interesting therapeutic perspectives.

We report on a case of EWSR1-PATZ1 rearranged brain tumor occurring in a 17 month-old child, originally interpreted as an infantile glioblastoma. Our case shows important analogies with the 2 previously reported cases, including the intraventricular location, the histologic appearance (pushing borders, oligodendrocyte-like morphology, rich vascular network) and the glioneural immunophenotype, supporting the role of these features as relevant clues to the diagnosis. On the other hand, our case displays unique characteristics, i.e. the onset in an infant, the presence of a focal high-grade component and the leptomeningeal dissemination, pointing to the importance of considering this entity in the differential diagnosis of an infantile glial/glioneural tumor.

Medulloblastoma (MB) is a childhood malignant brain tumour comprising four main subgroups characterized by different genetic alterations and rate of mortality. Among MB subgroups, patients with enhanced levels of the c-MYC oncogene (MBGroup3) have the poorest prognosis. Here we identify a previously unrecognized role of the pro-autophagy factor AMBRA1 in regulating MB. We demonstrate that AMBRA1 expression depends on c-MYC levels and correlates with Group 3 patient poor prognosis; also, knockdown of AMBRA1 reduces MB stem potential, growth and migration of MBGroup3 stem cells. At a molecular level, AMBRA1 mediates these effects by suppressing SOCS3, an inhibitor of STAT3 activation. Importantly, pharmacological inhibition of autophagy profoundly affects both stem and invasion potential of MBGroup3 stem cells, and a combined anti-autophagy and anti-STAT3 approach impacts the MBGroup3 outcome. Taken together, our data support the c-MYC/AMBRA1/STAT3 axis as a strong oncogenic signalling pathway with significance for both patient stratification strategies and targeted treatments of MBGroup3.

Pediatric low-grade gliomas (pLGGs) are the most frequent brain tumor in children. Adjuvant treatment, consisting in chemotherapy and radiotherapy, is often necessary if a complete surgical resection cannot be obtained. Traditional treatment approaches result in a significant long-term morbidity, with a detrimental impact on quality of life. Dysregulation of the mitogen-activated protein kinase (MAPK) pathway is the molecular hallmark of pLGGs and hyper-activation of the downstream mammalian target of rapamycin (mTOR) pathway is frequently observed. We report clinical and radiological results of front-line treatment with everolimus in 10 consecutive patients diagnosed with m-TOR positive pLGGs at the Bambino Gesu Children's Hospital in Rome, Italy. Median duration of treatment was 19 months (range from 13-60). Brain magnetic resonance imaging showed stable disease in 7 patients, partial response in 1 and disease progression in 2. Therapy-related adverse events were always reversible after dose reduction or temporary treatment interruption. To the best of our knowledge, this is the first report of everolimus treatment for chemo- and radiotherapy-naive children with pLGG. Our results provide preliminary support, despite low samples size, for the use of everolimus as target therapy in pLGG showing lack of progression with a manageable toxicity profile.

Background: Low-grade epilepsy-associated neuroepithelial tumors (LEATs) are a frequent etiology in pediatric patients with epilepsy undergoing surgery. Objective: To identify differences in clinical and post-surgical follow-up between patients with focal meningeal involvement (MI) and those without MI within our cohort of pediatric patients with LEATs. Methods: We retrospectively reviewed all pediatric patients (Results: We identified 37 patients: five with MI and 32 without. Half of patients (19) were drug sensitive at surgery; similar between groups. The group with MI differed mainly for age of epilepsy-onset (0.6 vs. 7.0 y) but not for epilepsy duration (0.9 vs. 1.5 y). Post-surgery radiological follow-up (median 4.0 y; IQR 2.8–5.0 y) did not indicate disease progression. Seizure outcome was excellent in both groups, with 34 patients overall being both drug- and seizure-free. Conclusions: Our study identified a new subgroup of LEATs with focal MI and excellent post-surgical outcome. Moreover, this highlights the effectiveness of early surgery in pediatric LEATs.

Noonan syndrome (NS) is a congenital autosomic dominant condition characterized by a variable spectrum from a clinical and genetical point of view. Germline mutations in more than ten genes involved in RAS–MAPK signal pathway have been demonstrated to cause the disease. An higher risk for leukemia and solid malignancies, including brain tumors, is related to NS. A review of the published literature concerning low grade gliomas (LGGs) in NS is presented. We described also a 13-year-old girl with NS associated with a recurrent mutation in PTPN11, who developed three different types of brain tumors, i.e., an optic pathway glioma, a glioneuronal neoplasm of the left temporal lobe and a cerebellar pilocytic astrocytoma. Molecular characterization of the glioneuronal tumor allowed to detect high levels of phosphorylated MTOR (pMTOR); therefore, a therapeutic approach based on an mTOR inhibitor (everolimus) was elected. The treatment was well tolerated and proved to be effective, leading to a stabilization of the tumor, which was surgical removed. The positive outcome of the present case suggests considering this approach for patients with RASopathies and brain tumors with hyperactivated MTOR signaling.

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No abstract available.

BACKGROUND: Neonatal acute liver failure (ALF) is a severe condition with a mortality rate up to 70%. Human enterovirus (HEV) infections are associated with serious diseases in newborns, including myocarditis, meningoencephalitis and, more rarely, ALF with a fulminant course. METHODS: Cases of neonatal-onset ALF were identified using the institutional clinical database. The history and clinical data of infants with HEV infection were collected by medical record revision. Viral testing by nested real- time PCR (nRT-PCR) was performed by the Bambino Gesù Children's Hospital Clinical Laboratory and by National Institute of Public Health in Rome. RESULTS: Among ten infants referred to our Institution with neonatal-onset ALF in the 2004-2018 period, we identified five cases due to HEV. In three of these, the mother reported an episode of mild fever and diarrhea during the last trimester of gestation, suggesting fetal-maternal transmission. All were late preterm infants (32-36 weeks). Two infants died as a result of ALF; the other three survived with full normalization of liver function. In four, the causing agents were coxsackie B serotypes 3 (n = 1), 4 (n = 1) and 5 (n = 2), in the fifth case we identified echovirus serotype 11. CONCLUSIONS: Human enterovirus (HEV) are a rare but relevant cause of ALF in neonates. HEV testing should be systematically performed in cases of neonatal ALF for diagnostic and management purposes.

BACKGROUND Medulloblastoma is the most frequent malignant brain tumor in children, still resulting fatal in about one third of affected patients. An accurate diagnosis is essential for correct therapeutic stratification. The DNA methylation profile (DMP) is a combination of changes in DNA methylation and genetic features that reflect the cell of tumor origin. DMP contributed to classify Medulloblastoma into four subgroups: WNT, SHH, Group 3/4 (the latter recently further subdivided into 8 subclasses). Each Methylation is associated with different genetic, demographic and clinical characteristics. We report our experience on Medulloblastoma molecular classification based on DMP. MATERIALS AND METHODS 54 Medulloblastoma patients (28 males, 26 females) were selected. The DMP analysis was carried out via IlluminaEPICarrays. The results were obtained using the brain tumor classifier (Capper, 2018). RESULTS In all cases the DMP allowed to classify the neoplasm, with an optimal score, in a defined methylation class. 10 WNTs, 15 SHHs, 10 Group 3, 19 Group 4 were found. Groups 3/4 were further refined based on the new consensus (Sharma 2019) in group I (n = 1); group II (n = 5); group III (n = 2); group IV (n = 4); group V (n = 3); group VI (n = 2); group VII (n = 6); group VIII (n = 7). CONCLUSIONS This study carried out the first classification of Medulloblastomas diagnosed in Italy through DMP, demonstrating its high reproducibility, precision and accuracy. The molecular classification improves diagnostic accuracy and provides further information that can guide personalized treatment.

INTRODUCTION Hematopoietic stem cell transplantation (HSCT) is increasingly used in the treatment of acute leukemias (AL), non-Hodgkin lymphomas and other primary malignancies. However, a growing number of neoplasms secondary to HSCT are reported. The combination of total body irradiation (TBI) and high dose chemotherapy (HD-CT) as conditioning regimen is considered a risk factor. We present four children who survived AL, treated with HSCT and conditioning regimens including TBI/HD-CT. These patients developed a high-grade-brain tumor. We analyzed histological and molecular characteristics of neoplasms. METHODS Histologically, tumors were assessed for: presence of mitosis, necrosis and vascular proliferation; expression of ki67; expression of neuronal and glial markers, p53 and therapeutic targets. We analyzed the DNA methylation profile (DMP) of all tumors using IlluminaEPICarrays and compared it to the brain tumor classifier which allowed to generate the CNVs. RESULTS Morphologically two cases were defined as anaplastic astrocytoma, two cases as glioblastoma. Based on the DMP, all cases were found to belong to the methylation class “glioblastoma, IDH wildtype, subclass midline”, hypermutants, with gain of chromosome 1q and loss of 1p. Two cases showed PDGFRA amplification. All patients were treated with Temozolomide combination therapy +/- Bevacizumab and radiation therapy. At progression three patients were treated with checkpoint inhibitors. CONCLUSIONS The improvement of the precision medicine is fundamental in the therapeutic decision of brain tumors and even more in neoplasms secondary to antiblastic treatments. DMP and CNV have proven to be useful tools to complement the histological characterization of the reported cases.

PURPOSE To develop a predictive grading model based on diffusion kurtosis imaging (DKI) metrics in children affected by gliomas, and to investigate the clinical impact of the model via correlations with overall survival and progression-free survival. MATERIALS AND METHODS We retrospectively studied 59 children (33M, 26F, median age 7.2 years) affected by gliomas on a 3T magnet. Patients with tumor locations other than infratentorial midline were included. Conventional and DKI sequences were obtained. Mean kurtosis (MK), axial kurtosis (AK), radial kurtosis (RK), fractional anisotropy (FA) and apparent diffusion coefficient (ADC) maps were obtained. Whole tumor volumes (VOIs) were segmented semiautomatically. Mean DKI values were calculated for each metric. The quantitative values from DKI-derived metrics were used to develop a predictive grading model with penalized logistic regression (glmnet package, R). Elasticnet regularization was used to avoid model overfitting. Fitted model coefficients from each metric were used to develop a probability prediction of a high-grade glioma (HGG). Grading accuracy of the resulting probabilities was tested with ROC analysis. Finally, model predictions were correlated to progression-free survival (PFS) with a Kaplan-Meier analysis. RESULTS The cohort included 46 patients with low-grade gliomas (LGG) and 13 patients with HGG. The developed model predictions yielded an AUC of 0.946 (95%CI: 0.890–1). Model predictions were significantly correlated with PFS (23.1 months for HGG vs 34.7 months for LGG, p CONCLUSION In our cohort, a DKI-based predictive model was highly accurate for pediatric glioma grading. DKI-based model predictions were significantly correlated with progression-free survival.

Background Development of in vitro models of pediatric brain tumors (pBT) is instrumental for both understanding the contributing oncogenic molecular mechanisms and identifying and testing new therapeutic strategies. Primary cell lines should be established and managed to prevent epigenetic and genetic alterations and thus recapitulating the original tumor. DNA methylation (DM) is a stable epigenetic modification, altered in cancer and recently used to classify tumors. We aim to apply DM and Copy Number Variation (CNV) profiling to characterize pBT primary cell lines and tumors. Methods We investigated 34 pBT tissues from different histology paired to 52 their derived primary cultures in both 2D and 3D conditions, as stem-cells or in serum-supplemented medium, and both short and long-terms in culture. We studied 18 additional pBT-derived cell-lines, 9 organoids, 5 commercial cell-lines, and 122 pBT tissues from the same histological categories, as controls, for a total of 240 genome-wide DM profiles. We analyzed DM and CNV profiles by using Illumina EPIC-arrays. By means of a bump hunting strategy, we identified differentially methylated regions in faithful vs unfaithful cell lines, and performed a functional characterization using over-representation analysis. Results The 69% (25/36) of cells at early passages retained genetic alteration and the same DM patterns of the original tumors, with no differences related to 2D/3D methods or the presence of serum in media. The 70% (24/34) of primary cell lines analyzed at later passages (>5 or >14 days in culture) diverged from the primary tumor, the totality of those cultured with serum. All divergent cells clustered together acquiring common deregulated epigenetic signature induced by serum culture media, 2D methods and longer time in culture. Conclusions We have shown that global DM profiles, along with CNV analysis are useful tools to detect the recapitulation of pBT-derived primary cell-lines from the original tumor. Whatever subgroups tested, our results suggest that in vitro models should be passaged as little as possible to retain the epigenetic and genetic alterations of the tumors and thus to be considered relevant for basic and translational biology.

Inherited optic neuropathies include complex phenotypes, mostly driven by mitochondrial dysfunction. We report an optic atrophy spectrum disorder, including retinal macular dystrophy and kidney insufficiency leading to transplantation, associated with mitochondrial DNA (mtDNA) depletion without accumulation of multiple deletions. By whole-exome sequencing, we identified mutations affecting the mitochondrial single-strand binding protein (SSBP1) in 4 families with dominant and 1 with recessive inheritance. We show that SSBP1 mutations in patient-derived fibroblasts variably affect the amount of SSBP1 protein and alter multimer formation, but not the binding to ssDNA. SSBP1 mutations impaired mtDNA, nucleoids, and 7S-DNA amounts as well as mtDNA replication, affecting replisome machinery. The variable mtDNA depletion in cells was reflected in severity of mitochondrial dysfunction, including respiratory efficiency, OXPHOS subunits, and complex amount and assembly. mtDNA depletion and cytochrome c oxidase-negative cells were found ex vivo in biopsies of affected tissues, such as kidney and skeletal muscle. Reduced efficiency of mtDNA replication was also reproduced in vitro, confirming the pathogenic mechanism. Furthermore, ssbp1 suppression in zebrafish induced signs of nephropathy and reduced optic nerve size, the latter phenotype complemented by WT mRNA but not by SSBP1 mutant transcripts. This previously unrecognized disease of mtDNA maintenance implicates SSBP1 mutations as a cause of human pathology.

Brain tumors are the most common solid neoplasms of childhood, but they are very rarely reported in children with Down Syndrome (DS), who develop more commonly different types of malignancies. In particular, we hereby report the case of an 8-years-old child with DS that presented to our attention for neurological and endocrinological issues. Brain imaging revealed the presence of a mass that was partially resected revealing a histological diagnosis of Pleomorphic Xanthoastrocytoma (PXA), a rare WHO grade II tumor extending from the diencephalic region into the surrounding brain tissue. These tumors can harbor the BRAF mutation p.V600E, targetable by the specific inhibitor Vemurafenib. After confirming the presence of the mutation in the tumor, the patient was treated with Vemurafenib. The treatment proved to be effective, leading to a partial response and a stabilization of the disease. Usually, in patients with DS a reduction of the dose of chemotherapeutic drugs is necessary. Vemurafenib was instead well-tolerated as the only observed adverse effect was grade I skin toxicity. This is, to our knowledge, the first case of a PXA reported in a child with DS and the first DS patient treated with Vemurafenib.

Solid tumours are characterized by a high structural complexity that is difficult to reproduce with common bidimensional (2D) systems. We developed an innovative fibrin-based hydrogel 3D model and tested it as platform to establish primary LGG cultures, otherwise difficult to maintain owing to the activation of senescence pathways. To date, 37 samples were cultured in both 2D and 3D platforms (19 astrocytomas and 18 gangliogliomas), with an average culture duration of 177+13 days, showing that the 3D-culture enables the stabilization of LGG. Whereas in the 2D-culture the cells showed overtime a significant reduction in the average culture days between each passage (average P1-P3:35+6 days; P3-P6: 29+5; >P6: 17+5), suggesting the selection of a peculiar clone, in the 3D-setting, we observed a more regular growth (average P1-P3:44+5 days; P3-P6: 64+20;>P6: 48+16). Cell lines identity was confirmed by short tandem repeats (STRs) and the immunohistochemical characterization (H&E, Ki67, tumour and differentiation markers) in 3D cultures revealed phenotype, cellular organization and proliferative rates closer to those observed in the onset samples, as compared to the 2D. We then analyzed the methylation profile and preliminary results suggest that the 2D lines evolve towards different lineages. The analysis of cell senescence using ß-galactosidase assay revealed a lower senescence in the 3D cultures (3D:12,28%+4,3% of the cells vs 2D:50,69%+18,46%; p=0,008). Lastly, we evaluated the responses to radiotherapy by MTS assay, and showed that 2D-cultured cells are more sensitive to treatment than 3D (2D: untreated, 0,0232+0,023, 160 Gy 0,089+0,025; 3D: untreated 0,235+0,09, 160 Gy 0,169+0,08), suggesting an overestimation of the efficacy of such treatment by the 2D-setting, therefore reducing the predictive power. The response to chemotherapy and more innovative approaches (i.e. Oncolytic Adenovirus) is currently under evaluation, the preliminary results confirming a similar finding. Overall, the 3D-culture offers an innovative platform for biological and therapeutic studies.

BACKGROUND Neurofibromatosis type 1 (NF1) is autosomal dominant neurogenetic disorder characterized by progressive cutaneous, neurologic, skeletal, and neoplastic manifestations. Plexiform neurofibromas (PN) are one of the different types of neurofibromas that occur in these patients. Complete surgical resection is difficult due to the tumor infiltrative behavior. We evaluated pegylated interferon- α-2b (PI) in patients with unresectable progressive or symptomatic PN. METHODS Pediatric patients (1–21 years old) affected by unresectable PN, followed at Bambino Gesù Hospital, were treated with PI. We administered PI as a weekly subcutaneous injection at a beginning dose of 1.0 mcg/kg/wk, increased to 3.0 mcg/kg/wk if well tolerated. Paracetamol (15mg/kg) was given 30 minutes prior the dose of PI and then every 4–6 hours as needed. Patients were evaluated with Magnetic Resonance Imaging (MRI) every 12 months after treatment start in case of stable disease. RESULTS 10 patients (3 females, 7 males) were enrolled. Median age was 12 years old. The median duration of treatment was 12,6 months. Grade 3 neutropenia (30%) and increased liver transaminases level (20%) were the most common toxicity. 6/10 patients experienced an improvement about pain. 7/10 patients showed clinical response. 1/10 patient had a radiological response at MRI, 1/10 experienced progression disease and 8/10 showed a stable disease at MRI evaluation. CONCLUSIONS Our study demonstrated that PI could be a suitable treatment for unresectable PN in terms of stabilization of the tumour size due to its antitumor activity although clinical response does not correlate with radiographic changes.

INTRODUCTION Pediatric brain tumors (PBT) represent the second most common pediatric cancer, with the highest mortality rate among childhood malignancies. Improvement of PBT diagnostic accuracy is fundamental to optimize treatment strategy. OBJECTIVES: We aimed to explore the impact of DNA methylation arrays implementation in PBT clinical practice. METHODS 214 PBT were analyzed by Illumina 850KEPICmethylation array. Low score and discordant cases were collegially reviewed. RESULTS Calibrated score was 0.8 or higher in 159 cases (74.3%), with pathological diagnosis confirmation in 132 cases and molecular subgroup definition in 47 of them, including cases of medulloblastoma, CNS neuroblastoma FOXR2, HGNET MN1; methylation profiling amended diagnosis in 10 cases, e.g. HGNET BCOR and anaplastic PXA, was non-contributory in 4 and misleading in 12 cases, including glioneural tumors and tumors arising in syndromic contexts. Calibrated score ranged between 0.8 and 0.3 in 37 cases (17.3%) and was below 0,3 (no match) in 18 cases (8.4%). Calibrated score below 0,8 was more frequently assigned to low grade gliomas and low grade glioneural tumors (p CONCLUSION Methylation profiling refine on diagnostic accuracy in PBT classification. Improvements are needed in classifying low grade glioma/glioneuronal tumors and challenging/very rare PBT. In syndromic cases, there is a high rate of misleading profiles and/or low scores.

Hemolytic uremic syndrome (HUS) is defined by the simultaneous occurrence of hemolytic anemia, thrombocytopenia, and acute kidney injury due to thrombotic microangiopathy (TMA) mainly occurring in renal and cerebral microvessels. Although the most common cause of HUS in children is Shiga toxin-producing Escherichia coli, atypical forms in which Shiga toxin is not the trigger may occur. Research over the last few years has shown that complement dysregulation secondary to mutations of genes coding for proteins involved in the regulation of the alternative pathway of complement account for most forms of atypical HUS (aHUS). Among these, thrombomodulin (THBD) gene mutations, representing 3–5% of all alternative pathway complement component abnormalities, correlate with early disease onset and rapid evolution to end-stage renal failure. aHUS onset is generally sudden, but occasionally the only manifestations of renal TMA are arterial hypertension, proteinuria, and a progressive increase in serum creatinine. Nephrotic syndrome at disease onset is exceptional. We describe the case of an adolescent female who presented with peripheral edema due to nephrotic-range proteinuria with bioptic evidence of TMA. Study of the alternative complement pathway showed a heterozygous missense THBD gene mutation (P501L variant) consistent with aHUS diagnosis. One year later she developed clinical signs of hemolytic anemia. Eculizumab, an anti-C5 monoclonal antibody, was started with rapid improvement. This case report highlights the phenotypic variability in aHUS due to THBD gene mutation. Early diagnosis by renal biopsy followed by genetic screening is required to optimize management in such a rare disease with a severe prognosis.

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Diffuse intrinsic pontine glioma (DIPG) and pediatric glioblastoma (pGBM) are heterogeneous brain tumors characterized by different anatomical and molecular subgroups and the presence of genetically and phenotypically distinct subclonal cell populations. It is recognized that exosomes mediate cross-talk among tumor cells. We hypothesize that there are different exosome-mediated paracrine signaling promoting tumour progression in DIPG and pGBM. Our aim was to determine the specific DIPG and pGBM-derived exosome oncogenic signatures. We used a panel of fifteen patient primary-derived cell lines, which included nine DIPG (seven H3.3 K27M, one H3.3 K27M/ACVR1 and one H3.1 K27M/ACVR1), one diffuse midline glioma H3.3 K27M and three GBM (one H3.3 G34R and two histone WT). Conditioned medium was collected from cells maintained under stem-cell culture condition, adherent on laminin and/or as neurospheres (NS), and exosomes harvested through serial centrifugations. Electron microscopy demonstrated that the isolated microvescicles are exosomes sized between 50–80 nm. DIPG derived-exosomes appeared to have a variable cargo of total protein (µg)/10(6) cells, which was higher than for pGBM-exosomes. Proteomic analysis revealed that proteins associated with vesicle docking, exocytosis and synaptic transmission were exclusively enriched in pontine-derived exosomes, while cell-cell and cell-matrix interaction proteinswere exclusive tohemispheric ones. Proteins in common to the two locations were involved in metabolism and energy pathways. Interestingly, principle component analysis on the different molecular subgroups suggests that ACVR1 may be not implicated in the exosomal proteomic signature. Exosomal miRNA profile appeared to be driven by the two main histone mutated subgroups H3.3 K27M and H3.1 K27M with the latter overexpressing hypoxia and angiogenic-associated miRNAs, leading to distinct oncogenic programs with different specific potential therapeutic targets. This study aimed to development new diagnostic/prognostic tools for DIPG and pGBM patients. Further investigations are aimed to identify new therapeutic strategies to inhibit the cross-talk among glioma subpopulations.

We present 47 consecutive patients operated at our Center for medulloblastoma in the last 5 years. Twenty five were males and mean age was 7 years. Eleven patients were infants. Surgery aimed at maximal safe resection in all cases. Molecular subgroup showed 7 WNT, 11 SHH, 14 Group 3, 15 Group 4. We tested a possible correlation between clinical variables relevant for surgery and molecular subgroup (Chi square test, significance = p

Extraventricular neurocytoma (EVN) is an extremely rare tumor of neuroglial origin with a tendency toward ganglionic or glial differentiation. In the 2016 World Health Organization Classification, EVN was classified as a grade II tumor and described as a neoplasm with good outcome. However, the presence of cellular atypia is an important unfavorable prognostic factor. Here, we describe the first case of a patient with a congenital EVN localized in the brainstem. After a sub-total resection, his disease rapidly progressed despite several chemotherapies, including molecular targeting approaches. He died 13 months after diagnosis. In conclusion, we report an atypical case of EVN presenting an extremely aggressive behavior, despite the absence of cellular atypia. The brainstem origin and the age of the patient may have represented two important prognostic factors for our patient.

Extraventricular neurocytoma (EVN) is a rare primary brain tumor occurring in brain parenchyma outside the ventricular system. Histopathological characteristics resemble those of central neurocytoma but exhibit a wider morphologic spectrum. Accurate diagnosis of these histologically heterogeneous tumors is often challenging because of the overlapping morphological features and the lack of defining molecular markers. Here, we explored the molecular landscape of 40 tumors diagnosed histologically as EVN by investigating copy number profiles and DNA methylation array data. DNA methylation profiles were compared with those of relevant differential diagnoses of EVN and with a broader spectrum of diverse brain tumor entities. Based on this, our tumor cohort segregated into different groups. While a large fraction (n = 22) formed a separate epigenetic group clearly distinct from established DNA methylation profiles of other entities, a subset (n = 14) of histologically diagnosed EVN grouped with clusters of other defined entities. Three cases formed a small group close to but separated from the epigenetically distinct EVN cases, and one sample clustered with non-neoplastic brain tissue. Four additional samples originally diagnosed otherwise were found to molecularly resemble EVN. Thus, our results highlight a distinct DNA methylation pattern for the majority of tumors diagnosed as EVN, but also indicate that approximately onethird of morphological diagnoses of EVN epigenetically correspond to other brain tumor entities. Copy number analysis and confirmation through RNA sequencing revealed FGFR1–TACC1 fusion as a distinctive, recurrent feature within the EVN methylation group (60%), in addition to a small number of other FGFR rearrangements (13%). In conclusion, our data demonstrate a specific epigenetic signature of EVN suitable for characterization of these tumors as a molecularly distinct entity, and reveal a high frequency of potentially druggable FGFR pathway activation in this tumor group.

Granular cell tumors (GCTs) or Abrikossoff's tumors are rare, soft tissue tumors of neural origin with a generally benign behavior. They can occur anywhere in the body (with up to 7%–16% situated in the vulva) and can occur in patients of any age, being considered rare in children. A 6 year-old girl presented with a clitoral mass, surgically removed. Pathology revealed GCT of clitoris. To our knowledge this is the first case of GCT of the clitoris in the pediatric (prepubertal) age group reported in English literature. Although rare in pediatric age, GCT has to be suspected as a cause of vulvar mass. Surgical treatment and clinical follow-up must consider the possibility of recurrence, multiple location and malignancy with time.

A two year-old male was seen to our Emergency Department for acute abdominal pain, urinary retention and worsening constipation. A first level diagnostic imaging showed a pelvic cystic mass between bladder and rectum. Left kidney was absent. Further workup with MRI and endoscopy demonstrated the cyst to be of urogenital origin. Rapid increase in size and clinical symptoms prompted surgery. Pathology and surgical specimen showed the mass to be a left seminal vesicle cyst secondary to a malformation of the eiaculatory duct and embriologically related to ipsilateral renal agenesis. Such findings were consistent with the diagnosis of Zinner’s syndrome (a clinical triad consisting of seminal vesicle cyst, ejaculatory duct obstruction and ipsilateral renal agenesis). Since the symptoms related to the seminal vesicle cyst coincide with the onset of a sexually active life, the majority of cases are generally observed and treated in the second and third decade. To our knowledge, this is the first case description in pediatric age.

Medulloblastoma (MB) is the most common malignant brain tumor in children. Despite therapeutic advancements, high-risk groups still present significant mortality. A deeper knowledge of the signaling pathways contributing to MB formation and aggressiveness would help develop new successful therapies. The target of rapamycin, mTOR signaling, is known to be involved in MB and is already targetable in the clinical setting. Furthermore, mTOR is a master metabolic regulator able to control cell growth versus autophagy decisions in conditions of amino-acid deprivation that can be due to IDO1 enzymatic activity. IDO1 has been also implicated in the regulation of inflammation, as well as of T cell-mediated immune responses, in a variety of pathological conditions, including brain tumors. In particular, IDO1 induces expansion of regulatory T-cells (Treg), preventing immune response against tumor cells. Analysis of 27 MB tissue specimens for the expression of both mTOR and IDO1 showed their widespread expression in all samples. Testing their cooperation in vitro, a significant involvement of IDO1 in mTOR immunogenic pathway was found, able to counteract the aim of rapamycin treatment. In MB cell lines, inhibition of mTOR strongly induced IDO1 expression and activity, corroborating its ability to recruit Treg cells in the tumor microenvironment. The mTOR/IDO1 cross talk was found to be strictly specific of MB cells. We demonstrated that mTOR pathway cross talks with IDO1 pathway to promote MB immune escape, possibly contributing to failure of mTOR- targeted therapy.