Nlrp2 deletion ameliorates kidney damage in a mouse model of cystinosis

Cystinosis is a rare autosomal recessive disorder caused by mutations in the CTNS gene that encodes cystinosin, a ubiquitous lysosomal cystine/H+ antiporter. The hallmark of the disease is progressive accumulation of cystine and cystine crystals in virtually all tissues. At the kidney level, human cystinosis is characterized by the development of renal Fanconi syndrome and progressive glomerular and interstitial damage leading to end-stage kidney disease in the second or third decade of life. The exact molecular mechanisms involved in the pathogenesis of renal disease in cystinosis are incompletely elucidated. We have previously shown upregulation of NLRP2 in human cystinotic proximal tubular epithelial cells and its role in promoting inflammatory and profibrotic responses. Herein, we have investigated the role of NLRP2 in vivo using a mouse model of cystinosis in which we have confirmed upregulation of Nlrp2 in the renal parenchyma. Our studies show that double knock out Ctns-/- Nlrp2-/- animals exhibit delayed development of Fanconi syndrome and kidney tissue damage. Specifically, we observed at 4-6 months of age that animals had less glucosuria and calciuria and markedly preserved renal tissue, as assessed by significantly lower levels of inflammatory cell infiltration, tubular atrophy, and interstitial fibrosis. Also, the mRNA expression of some inflammatory mediators (Cxcl1 and Saa1) and the rate of apoptosis were significantly decreased in 4-6-month old kidneys harvested from Ctns-/- Nlrp2-/- mice compared to those obtained from Ctns-/-mice. At 12-14 months of age, renal histological was markedly altered in both genetic models, although double KO animals had lower degree of polyuria and low molecular weight proteinuria and decreased mRNA expression levels of Il6 and Mcp1. Altogether, these data indicate that Nlrp2 is a potential pharmacological target for delaying progression of kidney disease in cystinosis.

Histologic and Clinical Factors Associated with Kidney Outcomes in IgA Vasculitis Nephritis

BACKGROUND

Nephritis is a common manifestation of IgA vasculitis and is morphologically indistinguishable from IgA nephropathy. While MEST-C scores are predictive of kidney outcomes in IgA nephropathy, their value in IgA vasculitis nephritis has not been investigated in large multiethnic cohorts.

METHODS

Biopsies from 262 children and 99 adults with IgA vasculitis nephritis ( N =361) from 23 centers in North America, Europe, and Asia were independently scored by three pathologists. MEST-C scores were assessed for correlation with eGFR/proteinuria at biopsy. Because most patients ( N =309, 86%) received immunosuppression, risk factors for outcomes were evaluated in this group using latent class mixed models to identify classes of eGFR trajectories over a median follow-up of 2.7 years (interquartile range, 1.2-5.1). Clinical and histologic parameters associated with each class were determined using logistic regression.

RESULTS

M, E, T, and C scores were correlated with either eGFR or proteinuria at biopsy. Two classes were identified by latent class mixed model, one with initial improvement in eGFR followed by a late decline (class 1, N =91) and another with stable eGFR (class 2, N =218). Class 1 was associated with a higher risk of an established kidney outcome (time to ≥30% decline in eGFR or kidney failure; hazard ratio, 5.84; 95% confidence interval, 2.37 to 14.4). Among MEST-C scores, only E1 was associated with class 1 by multivariable analysis. Other factors associated with class 1 were age 18 years and younger, male sex, lower eGFR at biopsy, and extrarenal noncutaneous disease. Fibrous crescents without active changes were associated with class 2.

CONCLUSIONS

Kidney outcome in patients with biopsied IgA vasculitis nephritis treated with immunosuppression was determined by clinical risk factors and endocapillary hypercellularity (E1) and fibrous crescents, which are features that are not part of the International Study of Diseases of Children classification.

PATZ1-Rearranged Tumors of the Central Nervous System: Characterization of a Pediatric Series of Seven Cases

PATZ1-rearranged sarcomas are well-recognized tumors as part of the family of round cell sarcoma with EWSR1-non-ETS fusions. Whether PATZ1-rearranged central nervous system (CNS) tumors are a distinct tumor type is debatable. We thoroughly characterized a pediatric series of PATZ1-rearranged CNS tumors by chromosome microarray analysis (CMA), DNA methylation analysis, gene expression profiling and, when frozen tissue is available, optical genome mapping (OGM). The series consisted of 7 cases (M:F=1.3:1, 1-17 years, median 12). On MRI, the tumors were supratentorial in close relation to the lateral ventricles (intraventricular or iuxtaventricular), preferentially located in the occipital lobe. Two major histologic groups were identified: one (4 cases) with an overall glial appearance, indicated as "neuroepithelial" (NET) by analogy with the corresponding methylation class (MC); the other (3 cases) with a predominant spindle cell sarcoma morphology, indicated as "sarcomatous" (SM). A single distinct methylation cluster encompassing both groups was identified by multidimensional scaling analysis. Despite the epigenetic homogeneity, unsupervised clustering analysis of gene expression profiles revealed 2 distinct transcriptional subgroups correlating with the histologic phenotypes. Interestingly, genes implicated in epithelial-mesenchymal transition and extracellular matrix composition were enriched in the subgroup associated to the SM phenotype. The combined use of CMA and OGM enabled the identification of chromosome 22 chromothripsis in all cases suitable for the analyses, explaining the physical association of PATZ1 to EWSR1 or MN1. Six patients are currently disease-free (median follow-up 30 months, range 12-92). One patient of the SM group developed spinal metastases at 26 months from diagnosis and is currently receiving multimodal therapy (42 months). Our data suggest that PATZ1-CNS tumors are defined by chromosome 22 chromothripsis as causative of PATZ1 fusion, show peculiar MRI features (eg, relation to lateral ventricles, supratentorial frequently posterior site), and, although epigenetically homogenous, encompass 2 distinct histologic and transcriptional subgroups.

Monogenic systemic lupus erythematosus onset in a 13-year-old boy with Noonan like-syndrome: a case report and literature review

BACKGROUND

Childhood systemic lupus erythematosus (cSLE) has been considered as a polygenic autoimmune disease; however, a monogenic lupus-like phenotype is emerging with the recent recognition of several related novel high-penetrance genetic variants. RASopathies, a group of disorders caused by mutations in the RAS/MAPK pathway, have been recently described as a cause of monogenic lupus.

CASE PRESENTATION

We present a 13-year-old boy with Noonan-like syndrome with loose anagen hair who developed a monogenic lupus. The renal biopsy confirmed a class III lupus nephritis and identified the presence of zebra bodies.

CONCLUSIONS

RASopathies represent a cause of monogenic lupus. We report a new case of monogenic lupus in a child with Noonan-like syndrome with loose anagen hair. Lupus nephritis which has never been described in this context, may be part of the presentation. The presence of zebra bodies in SLE or RASopathies in unclear, but no other known conditions (Fabry disease or drugs) were identified as the cause of zebra bodies in our patient.

Successful treatment with avacopan (CCX168) in a pediatric patient with C3 glomerulonephritis

BACKGROUND

C3 glomerulonephritis (C3GN) is a subtype of C3 glomerulopathy (C3G), characterized by dysregulation of the alternative pathway of complement and by dominant C3 by immunofluorescence on the kidney biopsy. There is no approved treatment for patients with C3G. Immunosuppressive drugs as well as biologics have been used with limited success. In recent decades, substantial advances in the understanding of the complement system have led to the development of new complement inhibitors. Avacopan (CCX168) is an orally administered small-molecule C5aR antagonist that blocks the effects of C5a, one of the most potent pro-inflammatory mediators of the complement system.

CASE REPORT

We describe a child with biopsy-proven C3GN treated with avacopan. She was enrolled in the ACCOLADE double-blind placebo-controlled Phase 2 study (NCT03301467), where during the first 26 weeks she was randomized to receive an avacopan-matching placebo orally twice daily, while in the following 26 weeks, the study was open-label and she received avacopan. After a wash-out period, she was restarted on avacopan through an expanded access program.

CONCLUSIONS

In this case, use of avacopan in a pediatric patient with C3GN was safe and well tolerated. On avacopan, the patient was able to discontinue mycophenolate mofetil (MMF) while maintaining remission.

A Rare Ovarian Tumor: The Sclerosing Stromal You Do Not Expect-A Case Series in the Adolescent Population and a Literature Review

Sclerosing stromal tumor (SST) is a rare ovarian tumor arising from the sex cord-stromal cells that occurs mainly in young adults during the second and third decades of life and rarely in pediatric and adolescent populations. The objective of this study is to report three illustrative cases of SST in young girls who had undergone surgery at our clinic in or after 2009, and to perform a literature review of this rare ovarian tumor. A retrospective chart review of female patients aged <18 years with a diagnosis of SST treated in a tertiary pediatric hospital was performed. Furthermore, a 10-year review of the SST literature was completed. Three cases of SST at our institution were outlined. After reviewing the literature, 18 SST cases were identified. The mean age at diagnosis was 13.4 years, and the reported clinical presentations were abdominal or pelvic pain and menstrual irregularity. Seven patients had abnormal hormone tests or CA-125 levels. In approximately 30% of cases, conservative surgery was performed, preserving residual ovarian tissue. In conclusion, some preoperative findings may help in suggesting the presence of SST. However, definitive diagnosis can only be made by histopathological examination. It is important to consider this tumor because, given its benign behavior, a conservative approach is preferred, particularly in this age group.

Paediatric-type diffuse high-grade gliomas in the 5th CNS WHO Classification

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.

Dual IGF1R/IR inhibitors in combination with GD2-CAR T-cells display a potent anti-tumor activity in diffuse midline glioma H3K27M-mutant

BACKGROUND

Diffuse midline gliomas (DMG) H3K27M-mutant, including diffuse intrinsic pontine glioma (DIPG), are pediatric brain tumors associated with grim prognosis. Although GD2-CAR T-cells demonstrated significant anti-tumor activity against DMG H3K27M-mutant in vivo, a multimodal approach may be needed to more effectively treat patients. We investigated GD2 expression in DMG/DIPG and other pediatric high-grade gliomas (pHGG) and sought to identify chemical compounds that would enhance GD2-CAR T-cell anti-tumor efficacy.

METHODS

Immunohistochemistry in tumor tissue samples and immunofluorescence in primary patient-derived cell lines were performed to study GD2 expression. We developed a high-throughput cell-based assay to screen 42 kinase inhibitors in combination with GD2-CAR T-cells. Cell viability, western blots, flow-cytometry, real time PCR experiments, DIPG 3D culture models, and orthotopic xenograft model were applied to investigate the effect of selected compounds on DIPG cell death and CAR T-cell function.

RESULTS

GD2 was heterogeneously, but widely, expressed in the tissue tested, while its expression was homogeneous and restricted to DMG/DIPG H3K27M-mutant cell lines. We identified dual IGF1R/IR antagonists, BMS-754807 and linsitinib, able to inhibit tumor cell viability at concentrations that do not affect CAR T-cells. Linsitinib, but not BMS-754807, decreases activation/exhaustion of GD2-CAR T-cells and increases their central memory profile. The enhanced anti-tumor activity of linsitinib/GD2-CAR T-cell combination was confirmed in DIPG models in vitro, ex vivo, and in vivo.

CONCLUSION

Our study supports the development of IGF1R/IR inhibitors to be used in combination with GD2-CAR T-cells for treating patients affected by DMG/DIPG and, potentially, by pHGG.

Urine-Derived Kidney Progenitor Cells in Cystinosis

Nephropathic cystinosis is an inherited lysosomal storage disorder caused by pathogenic variants in the cystinosin (CTNS) gene and is characterized by the excessive shedding of proximal tubular epithelial cells (PTECs) and podocytes into urine, development of the renal Fanconi syndrome and end-stage kidney disease (ESKD). We hypothesized that in compensation for epithelial cell losses, cystinosis kidneys undertake a regenerative effort, and searched for the presence of kidney progenitor cells (KPCs) in the urine of cystinosis patients. Urine was cultured in a specific progenitor medium to isolate undifferentiated cells. Of these, clones were characterized by qPCR, subjected to a differentiation protocol to PTECs and podocytes and assessed by qPCR, Western blot, immunostainings and functional assays. Cystinosis patients voided high numbers of undifferentiated cells in urine, of which various clonal cell lines showed a high capacity for self-renewal and expressed kidney progenitor markers, which therefore were assigned as cystinosis urine-derived KPCs (Cys-uKPCs). Cys-uKPC clones showed the capacity to differentiate between functional PTECs and/or podocytes. Gene addition with wild-type CTNS using lentiviral vector technology resulted in significant reductions in cystine levels. We conclude that KPCs present in the urine of cystinosis patients can be isolated, differentiated and complemented with CTNS in vitro, serving as a novel tool for disease modeling.

A clinical approach to children with C3 glomerulopathy

C3 glomerulopathy is a relatively new clinical entity that represents a challenge both to diagnose and to treat. As new therapeutic agents that act as complement inhibitors become available, many with an oral formulation, a better understanding of this disease and of the underlying complement dysregulation driving it has become increasingly useful to optimize patient care. Moreover, recent advances in research have clarified the role of complement in other glomerular diseases in which its role was less established, namely in immune-complex membranoproliferative glomerulonephritis (IC-MPGN), ANCA-vasculitis, IgA nephropathy, and idiopathic membranous nephropathy. Complement inhibitors are being studied in adult and adolescent clinical trials for these indications. This review summarizes current knowledge and future perspectives on every aspect of the diagnosis and management of C3 glomerulopathy and elucidates current understanding of the role of complement in this condition and in other glomerular diseases in children. An overview of ongoing trials involving therapeutic agents targeting complement in glomerular diseases is also provided.

Cystic Dysplasia of the Rete Testis: Case Report and Systematic Review of the Literature

Cystic dysplasia of the rete testis (CDRT) is a rare cause of testicular masses in children. The pathogenesis of this malformation remains unclear. It is often associated with other genitourinary anomalies, commonly presenting as agenesis or dysplasia of the ipsilateral kidney. A case involving a 9-year-old boy with a testicular lesion and ipsilateral renal agenesis, who was diagnosed with CDRT after histological examination, is reported. In addition, a systematic review of the literature was performed to better understand this pathology to design the most appropriate treatment and follow-up strategy for patients with CDRT.

Analysis of the mutational status of SIX1/2 and microRNA processing genes in paired primary and relapsed Wilms tumors and association with relapse

Whereas 90% of patients with Wilms tumor (WT) reach cure, approximately half of patients developing a recurrent tumor die of the disease. Therefore, to disclose events leading to recurrence represents a clinical need. To study paired primary/recurrent tumor samples, being aware of the intra-tumoral heterogeneity, might help finding these answers. We previously suggested that mutations in SIX1 and DROSHA underlie WT recurrence. With the aim to better investigate this scenario, we collected 19 paired primary/recurrent tumors and 10 primary tumors from relapsing patients and searched for mutations in the SIX1/2 genes and microRNA processing genes (miRNAPGs). We found SIX1 mutation in one case, miRNAPGs mutations in seven cases, and the co-occurrence of SIX1 and miRNAPG mutations in one case. We could observe that, whereas in primary tumors the mutations could be heterogeneously present, in all cases they were positively selected and homogeneously present in the recurrent disease, as also indicated by a "moderate" and "almost perfect" agreement (according to the Landis and Koch classification criteria) between paired samples. Analysis of SIX1/2 genes and miRNAPGs in 50 non-relapsing WTs disclosed SIX2 mutation in one case and miRNAPGs mutations in seven. A borderline statistically significant association was observed between miRNAPGs mutations and the occurrence of relapse (p value: 0.05). These data suggest that SIX1 and miRNAPGs mutations may provide an advantage during tumor progression to recurrence and can represent oncogenic drivers in WT development.

Synchronous Presentation of Rare Brain Tumors in Von Hippel-Lindau Syndrome

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.

ALK-rearranged histiocytosis: Report of two cases with involvement of the central nervous system

AIMS

Histiocytoses are a heterogeneous group of localized or disseminated diseases. Clinical presentation and patients' outcome vary greatly, ranging from mild to life-threatening disorders. Rare cases of systemic or localized histiocytosis harboring ALK rearrangement have been reported.

METHODS

Two cases of CNS histiocytosis were thoroughly investigated by implementing multiple molecular tests, i.e. FISH, RT-qPCR, NGS analysis.

RESULTS

In a 10-month old girl (patient #1), MRI showed two left hemispheric lesions and a right fronto-mesial lesion histologically consisting of a moderately cellular infiltrative proliferation, composed by CD68(PGM1)+/CD163+ spindle cells. ALK 5'/3'-imbalance and a KIF5B(exon 24)-ALK(exon 20) fusion were documented by RT-qPCR and NGS analysis, respectively. A subsequent CT scan showed multiple hepatic and pulmonary lesions. The patient was started on chemotherapy (vinblastine) associated to an ALK-inhibitor (Alectinib) with remarkable response. In a 11-year-old girl (patient #2), MRI showed a right frontal 1.5 cm lesion. Neuropathological examination revealed a histiocytic proliferation composed by medium sized CD68(PGM1)+/HLA-DR+ cells, showing moderate ALK1 positivity. ALK rearrangement and a KIF5B(exon 24)-ALK(exon 20) fusion were demonstrated also in this case. Subsequent CT, 18F-FDG-PET and MRI scans showed the presence of a single right femoral lesion, proved to be a fibrous cortical defect.

CONCLUSIONS

In ALK-histiocytoses, CNS involvement may occur as part of a systemic disease or, rarely, as its only primary disease localization, which could remain otherwise asymptomatic. The diagnosis often relies on neuropathological examination of brain biopsy, which may pose a diagnostic challenge due to the variable histopathological features. An integrated histological and molecular approach in such cases is recommended.

Rosette-Forming Glioneuronal Tumor of the Fourth Ventricle: A Case of Relapse Treated with Proton Beam Therapy

Rosette-forming glioneuronal tumors (RGNTs) are rare, grade I, central nervous system (CNS) tumors typically localized to the fourth ventricle. We describe a 9-year-old girl with dizziness and occipital headache. A magnetic resonance imaging (MRI) revealed a large hypodense posterior fossa mass lesion in relation to the vermis, with cystic component. Surgical resection of the tumor was performed. A RGNT diagnosis was made at the histopathological examination. During follow-up, the patient experienced a first relapse, which was again surgically removed. Eight months after, MRI documented a second recurrence at the local level. She was a candidate for the proton beam therapy (PBT) program. Three years after the end of PBT, the patient had no evidence of disease recurrence. This report underlines that, although RGNTs are commonly associated with an indolent course, they may have the potential for aggressive behavior, suggesting the need for treatment in addition to surgery. Controversy exists in the literature regarding effective management of RGNTs. Chemotherapy and radiation are used as adjuvant therapy, but their efficacy management has not been adequately described in the literature. This is the first case report published in which PBT was proposed for adjuvant therapy in place of chemotherapy in RGNT relapse.

"Protenuria in SLE: Is it always lupus?"

Proteinuria is one of the most typical manifestations of kidney involvement in Systemic Lupus Erythematosus (SLE). We report the case of a 23-year-old woman with a 6-year-long history of SLE presenting with proteinuria after a three-year remission on hydroxychloroquine. Kidney histological examination showed alterations inconsistent with lupus nephritis and suggestive of hydroxychloroquine toxicity or Fabry disease. The latter was confirmed by genetic assay.

IMG-19. RADIOMICS AND SUPERVISED DEEP LEARNING TO PREDICT MOLECULAR SUBGROUPS IN MEDULLOBLASTOMA BASED ON WHOLE TUMOR VOLUME LABELING: A SINGLE CENTER MULTIPARAMETRIC MR ANALYSIS

PURPOSE

Medulloblastoma (MB) is a complex pathology. Four molecular subgroups have been unveiled (Wingless-WNT, Sonic Hedgehog-SHH, Group 3-G3 and Group 4-G4), characterized by significant differences in patient clinical outcome. We investigated the utility of a radiomic analysis to predict molecular subgroups in patients with MB.

MATERIALS AND METHODS

We retrospectively evaluated 42 patients with histological diagnosis of MB, known molecular subgroup, and diagnostic MRI scan performed in our Institution on a 3 Tesla magnet. For each patient, FLAIR, ADC, T2 and contrast-enhanced MPRAGE sequences were analysed. Solid tumor volumes were segmented semiautomatically. 107 features were extracted for each sequence (Pyradiomics, Python). Features were tested for stability against labelling variations, selecting those presenting Intraclass Correlation Coefficient (ICC)>0.9 across all labelling variations and all sequences. Among the remaining features, relevant features were selected with an all-relevant wrapper algorithm (Boruta, R). Remaining features were used to predict MB subgroup with a Random Forest algorithm(R). The most relevant features were ranked based on Gini index (R).

RESULTS

83/107 features presented ICC >0.9 for all sequences. Boruta selected 10 features. Classification analysis yielded an out-of-bag (OOB) error rate of 0.6%, (99.4% accuracy). The most relevant features for classification were “simple” first-order features such as volume, major axis or shape.

CONCLUSION

This radiomic study yielded robust features, which showed high accuracy in predicting the molecular MB subgroups. Random forest algorithms are ideal for multiclass classification (eg. MB subgroups) and are intrinsically suited against overfitting. The most relevant for molecular classification were first-order features.

IMG-14. DEVELOPING A PREDICTIVE GRADING MODEL FOR CHILDREN WITH GLIOMAS BASED ON DIFFUSION KURTOSIS IMAGING METRICS: ACCURACY AND CLINICAL CORRELATIONS WITH SURVIVAL

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<0.004).

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.

SSBP1 mutations cause mtDNA depletion underlying a complex optic atrophy disorder

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.

Infant High-Grade Gliomas Comprise Multiple Subgroups Characterized by Novel Targetable Gene Fusions and Favorable Outcomes

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 commentary by Szulzewsky and Cimino, p. 904.This article is highlighted in the In This Issue feature, p. 890.

Intraventricular Ectopic Cerebellum

BACKGROUND

Cerebellar ectopy is a rare finding, with few cases previously reported. Intraventricular localized cerebellar ectopy was described in only 1 case within the fourth ventricle.

CASE DESCRIPTION

A 9-year-old girl suffered for 2 years from bilateral frontoparietal headaches, sometimes accompanied by vomiting and photophobia. Magnetic resonance imaging demonstrated an oval-shaped lesion within the left lateral ventricle, characterized by well-defined margins without a clear cleavage plane from the adjacent choroid plexus. The mass presented an intermediate signal on T1- and T2-weighted sequences, similar to gray matter, and reduced ADC values on ADC maps compared with white matter, with no enhancement after gadolinium-based contrast injection. After resection, macroscopic examination revealed an organoid structure with leptomeningeal lining and a clear-cut cortex and white matter components. Histology demonstrated normal cerebellum with a double-layered cortex and normal underlying white matter. The cerebellar ectopy was focally covered by bundles of capillary vascular structures covered by a monostratified ependymal cell lining, consistent with choroid plexus.

CONCLUSIONS

We describe, for the first time to our knowledge, the case of a child with ectopic cerebellar tissue harboring the supratentorial ventricular system. Plausible etiologic mechanism consists in the herniation of the cerebellar germinal tissue into the ventricular system through the ependyma, allowing cell migration to the supratentorial compartment, followed by maturation into the normal cerebellum.

Glanular Venous Malformation in Pediatric Age: An Uncommon Vascular Disorder

Glanular venous malformations are uncommon in pediatric patients. The diagnosis can be easily achieved by observation, even if color Doppler ultrasound is useful for a better characterization. Abdomino-pelvic MRI is necessary to assess the extension of complex lesions and check for associated anomalies. Several therapeutic options are reported in literature. We report 3 paediatric cases successfully treated by surgery with no complications and functional sequelae. Cosmetic results were satisfactory, with minimal surgical scarring. In our opinion, surgery for small glanular venous malformations is indicated within puberty to prevent traumatic bleeding and psychological impact.

Role of DNA Methylation Profile in Diagnosing Astroblastoma: A Case Report and Literature Review

Astroblastoma is a rare tumor of the central nervous system (CNS) with uncertain clinical behavior. Recently, DNA methylation profiling has been shown to provide a highly robust and reproducible approach for the classification of all CNS tumors across different age groups. By using DNA methylation profiling, a subset of CNS high-grade tumors with astroblastoma-like morphology characterized by the meningioma 1 gene (MN1) rearrangements, has been identified; they were termed “CNS high-grade neuroepithelial tumors with MN1 alteration” (CNS-HGNET-MN1). Here, we describe a case of CNS-HGNET-MN1 diagnosed by DNA methylation profiling, using Illumina Infinium HumanMethylationEPIC BeadChip (EPIC), that offers the opportunity to conduct a brief literature review. The patient presented with an episode of partial seizures involving the right hemisoma. A gross total resection was performed. No other treatment was proposed in light of the histological and molecular findings. After 21 months, the patient is disease-free in good clinical conditions. Also in view of this case, we recommend DNA-methylation profiling as an important tool for diagnosis and more effective patient stratification and management.

Vemurafenib Treatment of Pleomorphic Xanthoastrocytoma in a Child With Down Syndrome

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.

Direct Involvement of Cranial Nerve V at Diagnosis in Patients With Diffuse Intrinsic Pontine Glioma: A Potential Magnetic Resonance Predictor of Short-Term Survival

Background: Diffuse intrinsic pontine glioma (DIPG) has a dismal prognosis. Magnetic resonance imaging (MRI) remains the gold standard for non-invasive DIPG diagnosis. MRI features have been tested as surrogate biomarkers. We investigated the direct involvement of cranial nerve V (CN V) in DIPG at diagnosis and its utility as predictor of poor overall survival.

Materials and Methods: We examined MRI scans of 35 consecutive patients with radiological diagnosis of DIPG. Direct involvement of CN V was assessed on the diagnostic scans. Differences in overall survival (OS) and time to progression (TTP) were analyzed for involvement of CN V, sex, age, tumor size, ring enhancement, and treatment regimen. Correlations between involvement of CN V and disease dissemination, magnet strength and slice thickness were analyzed. Statistical analyses included Kaplan-Meier curves, log-rank test and Spearman's Rho.

Results: After excluding six long-term survivors, 29 patients were examined (15 M, 14 F). Four patients presented direct involvement of CN V. Histological data were available in 12 patients. Median OS was 11 months (range 3–23 months). Significant differences in OS were found for direct involvement of CN V (median OS: 7 months, 95% CI 1.1–12.9 months for involvement of CN V vs. 13 months, 95% CI 10.2–15.7 for lack of involvement of CN V, respectively, p < 0.049). Significant differences in TTP were found for the two treatment regimens (median TTP: 4 months, 95% CI 2.6–5.3 vs. 7 months, 95% CI 5.9–8.1, respectively, p < 0.027). No significant correlation was found between involvement of CN V and magnet strength or slice thickness (r = −0.201; p = NS). A trend toward positive correlation was found between direct involvement of CN V at diagnosis and dissemination of disease at follow-up (r = 0.347; p < 0.065).

Conclusions: In our cohort, direct involvement of CN V correlated with poor prognosis. Based on our data, we suggest that in DIPG direct involvement of CN V should be routinely evaluated on diagnostic scans.

Neonatal acute liver failure due to enteroviruses: a 14 years single NICU experience

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.

BRAF V600E Inhibitor (Vemurafenib) for BRAF V600E Mutated Low Grade Gliomas

Low-grade gliomas (LGG) are the most common central nervous system tumors in children. Prognosis depends on complete surgical resection. For patients not amenable of gross total resection (GTR) new approaches are needed. The BRAF mutation V600E is critical for the pathogenesis of pediatric gliomas and specific inhibitors of the mutated protein, such as Vemurafenib, are available. We investigated the safety and efficacy of Vemurafenib as single agent in pediatric patients with V600E⁺ LGG. From November 2013 to May 2018, 7 patients have been treated in our Institution; treatment was well-tolerated, the main concern being dermatological toxicity. The best responses to treatment were: 1 complete response, 3 partial responses, 1 stable disease, only one patient progressed; in one patient, the follow-up is too short to establish the clinical response. Two patients discontinued treatment, and, in both cases, immediate progression of the disease was observed. In one case the treatment was discontinued due to toxicity, in the other one the previously assessed BRAF V600E mutation was not confirmed by further investigation. Two patients, after obtaining a response, progressed during treatment, suggesting the occurrence of resistance mechanisms. Clinical response, with improvement of the neurologic function, was observed in all patients a few weeks after the therapy was started. Despite the limitations inherent to a small and heterogeneous cohort, this experience, suggests that Vemurafenib represents a treatment option in pediatric patients affected by LGG and carrying BRAF mutation V600E.

Protocol biopsies in pediatric renal transplantation: a precious tool for clinical management

BACKGROUND

Kidney transplantation is the best treatment for children with end-stage kidney disease. Early results have improved, but late graft loss is still a major problem. Non-invasive, fully reliable early biomarkers of acute rejection are currently missing.

METHODS

Our aim was to evaluate the efficacy of protocol biopsies (PBXs) in a pediatric population. During 11 years, 209 renal transplantations were performed in 204 pediatric patients. Biopsies were performed 3-6 months, 1 year, and 5 years after transplantation. Procedure-related complications were systematically looked for by means of ultrasound scans.

RESULTS

Unexpected findings (mainly subclinical rejections) requiring therapeutic intervention were found in 19.3% biopsies performed at 3-6 months, in 18.4% in 12-month biopsies and in none of those performed after 5 years. The 13.6% patients at 12-month biopsies and 23.6% at 5-year biopsies showed calcineurin inhibitor (CNI) toxicity. Interstitial fibrosis and tubular atrophy (IF/TA) was found in 17.6 and 83.6% of patients at 12-month and 5-year biopsies, respectively. Complications of the PBX were infrequent. Five-year estimated glomerular filtration rate (GFR) was not significantly different in patients who received treatment for any cause and patients with normal histology.

CONCLUSIONS

Although we do not have a control group, we may speculate that patients who received treatment returned to a "standard" condition possibly improving final outcome. Protocol biopsies are a powerful diagnostic tool for the management of pediatric renal transplant recipients. In view of the lack of evidence that biopsies taken 5 years after transplantation lead to any therapeutic change, their use should be reconsidered.

Allogeneic HSCT transfers wild-type cystinosin to nonhematological epithelial cells in cystinosis: First human report

Cystinosis is an autosomal recessive lysosomal storage disorder characterized by the defective transport of the amino acid cystine out of the lysosome due to a deficiency of cystinosin, the lysosomal cystine transporter. Patients have lysosomal cystine accumulation in various tissues, leading to cellular stress and damage, particularly in the kidney, cornea, and other extrarenal tissues. Cysteamine, a cystine-depleting agent, improves survival and delays the progression of disease, but it does not prevent the development of either renal failure or extrarenal complications. Furthermore, the drug has severe adverse effects that significantly reduce patient compliance. Allogeneic hematopoietic stem cell transplantation (HSCT) is currently established as a therapeutic option for many inborn errors of metabolism, where the main pathologic driving factor is an enzyme deficiency. Recent studies in the cystinosis mouse-model suggested that HSCT could be a curative treatment alternative to cysteamine therapy. We treated a 16-year-old boy who had infantile cystinosis and side effects of cysteamine therapy with HSCT. We were able to demonstrate successful transfer of the wild-type cystinosin protein and CTNS mRNA to nonhematological epithelial cells in the recipient, as well as a decrease in the tissue cystine-crystal burden. This is the first report of allogeneic HSCT in a patient with cystinosis, the prototype of lysosomal membrane-transporter disorders.

FGFR1:TACC1 fusion is a frequent event in molecularly defined extraventricular neurocytoma

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 one third 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.

Congenital Extra-Ventricular (Ganglio)Neurocytoma of the Brain Stem: A Case Report

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.

Nephrotic-Range Proteinuria and Peripheral Edema in a Child: Not Only Idiopathic Nephrotic Syndrome

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.

Expanding the molecular diversity and phenotypic spectrum of glycerol 3-phosphate dehydrogenase 1 deficiency

Transient infantile hypertriglyceridemia (HTGT1; OMIM #614480) is a rare autosomal recessive disorder, which manifests in early infancy with transient hypertriglyceridemia, hepatomegaly, elevated liver enzymes, persistent fatty liver and hepatic fibrosis. This rare clinical entity is caused by inactivating mutations in the GPD1 gene, which encodes the cytosolic isoform of glycerol-3-phosphate dehydrogenase. Here we report on four patients from three unrelated families of diverse ethnic origins, who presented with hepatomegaly, liver steatosis, hypertriglyceridemia, with or without fasting ketotic hypoglycemia. Whole exome sequencing revealed the affected individuals to harbor deleterious biallelic mutations in the GPD1 gene, including the previously undescribed c.806G > A (p.Arg269Gln) and c.640T > C (p.Cys214Arg) mutations. The clinical features in three of our patients showed several differences compared to the original reports. One subject presented with recurrent episodes of fasting hypoglycemia along with hepatomegaly, hypetriglyceridemia, and elevated liver enzymes; the second showed a severe liver disease, with intrahepatic cholestasis associated with kidney involvement; finally, the third presented persistent hypertriglyceridemia at the age of 30 years. These findings expand the current knowledge of this rare disorder, both with regard to the phenotype and molecular basis. The enlarged phenotypic spectrum of glycerol-3-phosphate dehydrogenase 1 deficiency can mimic other inborn errors of metabolism with liver involvement and should alert clinicians to recognize this entity by considering GPD1 mutations in appropriate clinical settings.

Anomalous vascularization in a Wnt medulloblastoma: a case report

BACKGROUND

Medulloblastoma is the most common malignant brain tumor in children. To date only few cases of medulloblastoma with hemorrhages have been reported in the literature. Although some studies speculate on the pathogenesis of this anomalous increased vascularization in medulloblastoma, the specific mechanism is still far from clearly understood. A correlation between molecular medulloblastoma subgroups and hemorrhagic features has not been reported, although recent preliminary studies described that WNT-subtype tumors display increased vascularization and hemorrhaging.

CASE PRESENTATION

Herein, we describe a child with a Wnt-medulloblastoma presenting as cerebellar-vermian hemorrhagic lesion. Brain magnetic resonance imaging (MRI) showed the presence of a midline posterior fossa mass with a cystic hemorrhagic component. The differential diagnosis based on imaging included cavernous hemangioma, arteriovenous malformation and traumatic lesion. At surgery, the tumor appeared richly vascularized as documented by the preoperative angiography.

CONCLUSIONS

The case we present showed that Wnt medulloblastoma may be associated with anomalous vascularization. Further studies are needed to elucidate if there is a link between the hypervascularization and the Wnt/β-catenin signaling activation and if this abnormal vasculature might influence drug penetration contributing to good prognosis of this medulloblastoma subgroup.

Pediatric spinal glioblastoma of the conus medullaris: a case report of long survival

High-grade gliomas of the spinal cord represent a rare entity in children. Their biology, behavior, and controversial treatment options have been discussed in a few pediatric cases. These tumors are associated with severe disability and poor prognosis. We report a case of a 4-year-old child diagnosed with an isolated glioblastoma multiforme of the conus medullaris. The patient underwent subtotal surgical excision, followed by adjuvant radiotherapy and oral chemotherapy. He is alive with mild neurologic deficits at 52 months after diagnosis. We describe the peculiar characteristics of this rare condition in pediatric oncology. We also provide an overview of current multidisciplinary therapeutic approaches and prognostic factors for this disease.

Spinal ependymoma in a patient with Kabuki syndrome: a case report

BACKGROUND

Kabuki syndrome is a rare disorder characterized by the association of mental retardation and postnatal growth deficiency with distinctive facial appearance, skeletal anomalies, cardiac and renal malformation. Two causative genes have been identified in patients with Kabuki syndrome. Mutation of KMT2D (MLL2) was identified in 55-80% of patients, while 9-14% of KMT2D negative patients have mutation in KDM6A gene. So far, few tumors have been reported in patients with Kabuki syndrome. We describe the first case of a patient with spinal ependymoma and Kabuki syndrome.

CASE PRESENTATION

A 23 years old girl followed at our Center for KMT2D mutated Kabuki syndrome since she was 4 years old presented with acute lumbar pain and intermittent tactile hyposthenia of the feet. Spine magnetic resonance revealed a lumbar endocanalar mass. She underwent surgical resection of the lesion and histologic examination showed a tanycytic ependymoma (WHO grade II).

CONCLUSION

Kabuki syndrome is not considered a cancer predisposition syndrome. Nonetheless, a number of tumors have been reported in patients with Kabuki syndrome. Spinal ependymoma is a rare disease in the pediatric and young adult population. Whereas NF2 mutations are frequently associated to ependymoma such an association has never been described in Kabuki syndrome. To our knowledge this is the first case of ependymoma in a KMT2D mutated Kabuki syndrome patient. Despite KMT2D role in cancer has previously been described, no genetic data are available for previously reported Kabuki syndrome patients with tumors. Nonetheless, the association of two rare diseases raises the suspicion for a common determinant.

Association between gastroesophageal reflux and endobronchial carcinoid: a case report

Children with neurological disorders may suffer from gastroesophageal reflux disease (GERD). Typical symptoms are vomiting, regurgitation and hematemesis. Patients present with respiratory symptoms only in cases with swallowing disorders causing chronic airway aspiration. We report the case of a patient affected by chromosome 8 p deletion syndrome with mental retardation, referred to our unit for suspected GERD. Chest X-ray, performed at admission for coexisting respiratory complaints, showed left lower lobe pneumonia; esophageal pH monitoring and upper endoscopy were normal for GERD. To rule out chronic airway aspiration, gastroesophageal 99 mTc scintigraphy with lung scan 18 to 24 h after a test meal and video fluoroscopy swallowing study were performed, both negative. Two months later, a second episode of left lower lobe pneumonia occurred. A chest CT scan was performed and showed an endobronchial mass; the biopsy taken during the broncoscopy was not conclusive. Surgical excision resulted in a diagnosis of pulmonary carcinoid. Bronchial carcinoids, although rare, should be taken into consideration as a potential cause of recurrent pneumonia even in the presence of demonstrated GERD where severe respiratory infections only occur with coexisting chronic pulmonary aspiration, even in neurologically impaired people.

Idiopathic membranous nephropathy associated with polycystic kidney disease

Membranous nephropathy (MN) and polycystic kidney disease are both relatively rare diseases in children. On rare exceptions, these two conditions have been associated in adults. We report here the first case of a pediatric patient with this association. This 6-year-old child presented with gross hematuria, nephrotic syndrome, and mild renal failure. A renal ultrasound subsequently revealed that the patient also had polycystic kidney disease.

Parapharyngeal neuroglial heterotopia in Pierre Robin sequence: MR imaging findings

Heterotopic neuroglial tissue is a rare lesion, occurring more frequently in the nasal cavities. Other rare locations are the orbit, the scalp, the palate, the pharynx, the parapharyngeal space and the lungs. They are usually detected occasionally because they are often asymptomatic, but sometimes they might present with dyspnoea, feeding difficulty, snorting and nasal flaring. Respiratory symptoms occur when heterotopic neuroglial tissue is located in the parapharyngeal space. We report a case of an infant affected by Pierre Robin sequence (PRS) who was admitted to our Institution for a worsening respiratory distress that was not explainable only by PRS.

Risk factors for cyclosporin A nephrotoxicity in children with steroid-dependant nephrotic syndrome

BACKGROUND AND OBJECTIVES

Cyclosporin A (CsA) is a well-established treatment for steroid-dependent nephrotic syndrome (SDNS) that may, however, cause chronic ischemic renal lesions. The objective of the study was to assess the prevalence of CsA nephrotoxicity (CsAN) in protocol biopsies of children with SDNS.

DESIGN, SETTINGS, PARTICIPANTS, & MEASUREMENTS

From 1990 through 2008, we performed 71 renal biopsies in 53 patients with SDNS. The mean CsA C2 levels were 466 +/- 134 ng/ml, and the mean duration of treatment was 4.7 +/- 2.0 yr before biopsy (range 2.9 to 12.7 yr).

RESULTS

CsAN was observed in 22 (31%) of 71 renal biopsies. Of these, 11 corresponded to isolated vascular or tubular lesions, and 11 corresponded to combined vascular and tubular lesions. The majority of CsAN lesions were mild (17 of 22). In no cases were lesions graded as severe. By regression analysis, CsAN was positively associated with the use of angiotensin-converting enzyme inhibitors (ACEIs) or angiotensin II receptor blockers (ARBs) and with hyperuricemia and negatively associated with minimal-change lesions. By multivariate analysis, only association with the use of ACEIs or ARBs retained significance. Stratification of the population according to CsA C2 levels showed increased risk for CsAN for C2 levels >600 ng/ml.

CONCLUSIONS

Mild to moderate CsAN occurs in approximately one third of patients who have SDNS and are treated with CsA for >3 yr. Our data suggest that patients who require high dosages of CsA or treatment for hypertension, in particular when ACEIs/ARBs are used, are at higher risk for CsAN.

Clinical significance of CXC chemokine receptor-4 and c-Met in childhood rhabdomyosarcoma

PURPOSE

The CXC chemokine receptor-4 (CXCR4)/stromal-derived factor-1 and c-Met/hepatocyte growth factor axes promote the metastatic potential of rhabdomyosarcoma cell lines in experimental models, but no data are available on their role in rhabdomyosarcoma tumors. The expressions of CXCR4 and c-Met were evaluated in primary tumors and isolated tumor cells in marrow, and were correlated with clinicopathologic variables and survival.

EXPERIMENTAL DESIGN

Forty patients with recently diagnosed rhabdomyosarcoma were retrospectively enrolled. CXCR4 and c-Met expression was investigated in primary tumors by immunohistochemistry, in isolated marrow-infiltrating tumor cells using double-label immunocytology. Results were expressed as the mean percentage of immunostained tumor cells.

RESULTS

CXCR4 and c-Met were expressed in >/=5% of tumor cells from 40 of 40 tumors, with 14 of 40 cases showing >/=50% of immunostained tumor cells (high expression). High CXCR4 expression correlated with alveolar histology (P = 0.006), unfavorable primary site (P = 0.009), advanced group (P < 0.001), marrow involvement (P = 0.007), and shorter overall survival and event-free survival (P < 0.001); high c-Met expression correlated with alveolar histology (P = 0.005), advanced group (P = 0.04), and marrow involvement (P = 0.02). In patients with a positive diagnosis for isolated tumor cells in marrow (n = 16), a significant enrichment in the percentage of CXCR4-positive (P = 0.001) and c-Met-positive (P = 0.003) tumor cells was shown in marrow aspirates compared with the corresponding primary tumors.

CONCLUSIONS

CXCR4 and c-Met are widely expressed in both rhabdomyosarcoma subtypes and, at higher levels, in isolated marrow-infiltrating tumor cells. High levels of expression are associated with unfavorable clinical features, tumor marrow involvement and, only for CXCR4, poor outcome. In rhabdomyosarcoma, CXCR4 and c-Met represent novel exploitable targets for disease-directed therapy.

Glomerulocystic kidney disease in hypomelanosis of Ito

Hypomelanosis of Ito (incontinentia pigmenti type I) was first described as a disorder characterized by unusual unilateral or bilateral cutaneous macular hypopigmented whorls, streaks and patches. Subsequently, neurologic, skeletal and ocular involvement were described. Kidney involvement has been reported only exceptionally. Here, we describe the case of a male infant with hypomelanosis of Ito with a prenatal diagnosis of bilateral enlargement of the kidneys, decreased corticomedullary differentiation and cysts located in the cortical and subcapsular regions. These findings were confirmed postnatally. The skin examination showed hypopigmented linear and round diffuse lesions located on the right leg and the arms. Ophthalmological examination showed anterior capsular and posterior subcapsular cataract of the left eye. Renal biopsy was characteristic of glomerulocystic kidney disease, whereas the skin biopsy confirmed the clinical diagnosis of hypomelanosis of Ito. Four other cases of kidney disease in hypomelanosis of Ito have been reported, including two cases characterized by cystic renal changes, indicating that gene abnormalities that cause hypomelanosis of Ito may also impair normal renal development, causing renal cystic changes.

Identification and subcellular localization of a new cystinosin isoform

Nephropathic cystinosis is a lysosomal disorder caused by functional defects of cystinosin, which mediates cystine efflux into the cytosol. The protein sequence contains at least two signals that target the protein to the lysosomal compartment, one of which is located at the carboxy terminal tail (GYDQL). We have isolated from a human kidney cDNA library a cystinosin isoform, which is generated by an alternative splicing of exon 12 that removes the GYDQL motif. Based on its last three amino acids, we have termed this protein cystinosin-LKG. Contrary to the lysosomal cystinosin isoform, expression experiments performed by transient transfection of green fluorescent protein fusion plasmids in HK2 cells showed that cystinosin-LKG is expressed in the plasma membrane, in lysosomes, and in other cytosolic structures. This subcellular localization of the protein was confirmed by transmission electron microscopy. In addition, immunogold labeling was observed in the endoplasmic reticulum and in the Golgi apparatus. Expression of the protein in renal tubular structures was also directly demonstrated by immunostaining of normal human kidney sections. The plasma membrane localization of cystinosin-LKG was directly tested by [35S]cystine flux experiments in COS-1 cells. In the presence of a proton gradient, a marked enhancement of intracellular cystine transport was observed in cells overexpressing this isoform. These data indicate that the expression of the gene products encoded by the CTNS gene is not restricted to the lysosomal compartment. These finding may help elucidate the mechanisms of cell dysfunction in this disorder.