Enhanced accuracy and reduced delay in diagnosing bone tumors within an expert sarcoma network: A nationwide study.

INTRODUCTION: Primary bone tumors encompass a range of rare and diverse lesions. Pathological diagnosis poses significant challenges, with histological discrepancies extensively studied in soft tissue sarcomas but lacking specific investigation in bone lesions. This study aimed to determine the rate of major diagnostic discrepancies in primary bone tumors, assessing whether initial histological analysis within an expert referral center network reduces this rate and final diagnostic delay. Additionally, we examined the impact of mandatory systematic re-reading by expert pathologists on diagnostic variation and readjustment. METHODS: Our study cohort comprised patients with primary bone tumors, drawn from the national prospective French sarcoma network database. A total of 1075 patients were included from 2018 to 2019. RESULTS: The cohort exhibited a major discrepancy rate of 24%. Within the expert referral centers network, 49 cases (7%) showed major diagnostic discrepancies in the initial analysis, compared to 207 cases (57%) outside the network (p < 0.001). Regarding the final diagnostic delay, a mean of 2.8 weeks (±4.9) was observed within the network, contrasting with 6.5 weeks (±9.1) outside the network (p < 0.001). Systematic re-reading by an expert pathologist facilitated diagnosis readjustment in 75% of the 256 cases, with 68% of all diagnostic variations occurring preoperatively. CONCLUSION: Early management within the expert network significantly reduced major diagnostic discrepancies and shortened the diagnosis delay by approximately a month. Expert pathologist systematic re-readings were responsible for diagnosis readjustments in three-quarters of cases, with two-thirds of all diagnostic variations occurring preoperatively, thereby mitigating the consequences of mistreatment.

Pediatric Tumors and Developmental Anomalies: A French Nationwide Cohort Study.

OBJECTIVE: To assess the associations between congenital abnormalities and pediatric malignancies and evaluate the potential underlying molecular basis by collecting information on pediatric patients with cancer and congenital abnormalities. STUDY DESIGN: Tumeur Et Développement is a national, prospective, and retrospective multicenter study recording data of children with cancer and congenital abnormalities. When feasible, blood and tumoral samples are collected for virtual biobanking. RESULTS: From June 2013 to December 2019, 679 associations between pediatric cancers and congenital abnormalities were recorded. The most represented cancers were central nervous system tumors (n = 139; 20%), leukemia and myelodysplastic syndromes (n = 123; 18.1%), and renal tumors (n = 101; 15%). Congenital abnormalities were not related to any known genetic disorder in 66.5% of cases. In this group, the most common anomaly was intellectual disability (22.3%), followed by musculoskeletal (14.2%) and genitourinary anomalies (12.4%). Intellectual disability was mostly associated with hematologic malignancies. Embryonic tumors (neuroblastoma, Wilms tumor, and rhabdomyosarcoma) were associated with consistent abnormalities, sometimes with a close anatomical neighborhood between the abnormality and the neoplasm. CONCLUSIONS: In the first Tumeur Et Développement analysis, 3 major themes have been identified: (1) germline mutations with or without known cancer predisposition, (2) postzygotic events responsible for genomic mosaicism, (3) coincidental associations. New pathways involved in cancer development need to be investigated to improve our understanding of childhood cancers.

Giant Cell Tumors With HMGA2::NCOR2 Fusion : Clinicopathologic, Molecular, and Epigenetic Study of a Distinct Entity.

Giant cell tumors (GCTs) with high mobility group AT-Hook 2 ( HMGA2 )::nuclear receptor corepressor 2 ( NCOR2 ) fusion are rare mesenchymal tumors of controversial nosology, which have been anecdotally reported to respond to CSFR1 inhibitors. Here, we performed a comprehensive study of 6 GCTs with HMGA2::NCOR2 fusion and explored their relationship with other giant cell-rich neoplasms. Tumors occurred in 4 females and 2 males ranging in age from 17 to 32 years old (median 24). Three lesions originated in subcutaneous soft tissue and 3 in bone. Tumor size ranged from 20 to 33 mm (median 27 mm). The lesions had a nodular/multinodular architecture and were composed of sheets of mononuclear "histiocytoid" cells with uniform nuclei intermingled with multinucleated giant cells. Mitotic activity was low and nuclear atypia and metaplastic bone were absent. Variable findings included necrosis, cystic degeneration, lymphocytic infiltrate (sometimes forming nodules), and xanthogranulomatous inflammation. On immunohistochemistry, all cases focally expressed pan-keratin and were negative with SATB2 and H3.3G34W. Whole RNA-sequencing was performed in all cases of GCT with HMGA2::NCOR2 fusion and a subset of giant cell-rich tumors (tenosynovial-GCT, n = 19 and "wild-type" GCT of soft tissue, n = 9). Hierarchical clustering of RNA-sequencing data showed that GCT with HMGA2::NCOR2 fusion formed a single cluster, independent of the other 2 entities. Methylome profiling showed similar results, but the distinction from "wild-type" GCT of soft tissue was less flagrant. Gene expression analysis showed similar levels of expression of the CSF1/CSFR1 axis between GCT with HMGA2::NCOR2 fusion and tenosynovial-GCT, supporting their potential sensitivity to CSFR1 inhibitors. Clinical follow-up was available for 5 patients (range: 10 to 64 mo; median 32 mo). Three patients (60%) experienced local recurrences, whereas none had distant metastases or died of disease. Overall, our study confirms and expands previous knowledge on GCT with HMGA2::NCOR2 fusion and supports its inclusion as an independent entity.

Sphingosine Kinase-1 Is Overexpressed and Correlates with Hypoxia in Osteosarcoma: Relationship with Clinicopathological Parameters.

The Sphingosine kinase-1/Sphingosine 1-Phosphate (SphK1/S1P) signaling pathway is overexpressed in various cancers, and is instrumental for the adaptation to hypoxia in a number of solid tumor models, but no data are available in osteosarcoma. Here we report that SphK1 and the S1P1 receptor are involved in HIF-1α accumulation in hypoxic osteosarcoma cells. FTY720 (Fingolimod), which targets SphK1 and S1P1, prevented HIF-1α accumulation, and also inhibited cell proliferation in both normoxia and hypoxia unlike conventional chemotherapy. In human biopsies, a significant increase of SphK1 activity was observed in cancer compared with normal bones. In all sets of TMA samples (130 cases of osteosarcoma), immunohistochemical analysis showed the hypoxic marker GLUT-1, SphK1 and S1P1 were expressed in tumors. SphK1 correlated with the GLUT-1 suggesting that SphK1 is overexpressed and correlates with intratumoral hypoxia. No correlation was found between GLUT-1 or SphK1 and response to chemotherapy, but a statistical difference was found with increased S1P1 expression in patients with poor response in long bone osteosarcomas. Importantly, multivariate analyses showed that GLUT-1 was associated with an increased risk of death in flat bone, whereas SphK1 and S1P1 were associated with an increased risk of death in long bones.

Detection and localization of calcium oxalate in kidney using synchrotron deep ultraviolet fluorescence microscopy.

Renal oxalosis is a rare cause of renal failure whose diagnosis can be challenging. Synchrotron deep ultraviolet (UV) fluorescence was assayed to improve oxalosis detection on kidney biopsies spatial resolution and sensitivity compared with the Fourier transform infrared microspectroscopy gold standard. The fluorescence spectrum of synthetic mono-, di- and tri-hydrated calcium oxalate was investigated using a microspectrometer coupled to the synchrotron UV beamline DISCO, Synchrotron SOLEIL, France. The obtained spectra were used to detect oxalocalcic crystals in a case control study of 42 human kidney biopsies including 19 renal oxalosis due to primary (PHO, n = 11) and secondary hyperoxaluria (SHO, n = 8), seven samples from PHO patients who received combined kidney and liver transplants, and 16 controls. For all oxalocalcic hydrates samples, a fluorescence signal is detected at 420 nm. These spectra were used to identify standard oxalocalcic crystals in patients with PHO or SHO. They also revealed micrometric crystallites as well as non-aggregated oxalate accumulation in tubular cells. A nine-points histological score was established for the diagnosis of renal oxalosis with 100% specificity (76-100) and a 73% sensitivity (43-90). Oxalate tubular accumulation and higher histological score were correlated to lower estimated glomerular filtration rate and higher urinary oxalate over creatinine ratio.

Head and neck Ewing sarcoma: French surgical practice analysis pleads for surgery centralization.

This study aimed to analyze surgical procedures for head and neck Ewing sarcoma (HNES) with regard to oncological, functional, and esthetic outcomes. A blinded multidisciplinary retrospective chart review of operated French HNES patients (Euro-EWING 99 trial, 1999-2014) was performed to assess patient/tumor characteristics, treatment details, and outcomes. Primary surgery without reconstruction was undertaken in 13 patients (emergency context/misdiagnosis). However, because of contaminated surgical margins, all patients had to undergo systematic postoperative radiotherapy. Twenty-six patients underwent multidisciplinary evaluation and were scheduled to undergo postchemotherapy surgery, with 19 patients scheduled for immediate reconstruction. All cases showed R0 margins after postchemotherapy surgery of the initial tumor bed by multidisciplinary surgical teams, while n = 3/4 of local relapses (very poor prognosis) had R1a margins after surgery of the residual tumor volume following chemotherapy. Only three surgical expertise centers operated on ≥ 4 patients over the 15-year period. Thirty patients developed long-term sequelae, with increased complications following radiotherapy. Referring patients to surgical expertise centers following a suspected diagnosis, with planned postchemotherapy surgery of the initial tumor bed at these centers, might limit the need for intralesional resections, allowing radical R0 resections and thus reducing long-term sequelae as well as the risk of secondary radio-induced malignancy by limiting the need for postoperative radiotherapy.

Lessons from a large nationwide cohort of 350 children with ovarian mature teratoma: A study in favor of ovarian-sparing surgery.

BACKGROUND: Ovarian mature teratoma (OMT) is a common ovarian tumor found in the pediatric population. In 10%-20% of cases, OMT occurs as multiple synchronous or metachronous lesions on ipsi- or contralateral ovaries. Ovarian-sparing surgery (OSS) is recommended to preserve fertility, but total oophorectomy (TO) is still performed. DESIGN: This study reviews the clinical data of patients with OMT, and analyzes risk factors for second events. A national retrospective review of girls under 18 years of age with OMTs was performed. Data on clinical features, imaging, laboratory studies, surgical reports, second events and their management were retrieved. RESULTS: Overall, 350 children were included. Eighteen patients (5%) presented with a synchronous bilateral form at diagnosis. Surgery was performed by laparotomy (85%) and laparoscopy (15%). OSS and TO were performed in 59% and 41% of cases, respectively. Perioperative tumor rupture occurred in 23 cases, independently of the surgical approach. Twenty-nine second events occurred (8.3%) in a median time of 30.5 months from diagnosis (ipsilateral: eight cases including one malignant tumor; contralateral: 18 cases; both ovaries: three cases). A large palpable mass, bilateral forms, at diagnosis and perioperative rupture had a statistical impact on the risk of second event, whereas the type of surgery or approach did not. CONCLUSION: This study is a plea in favor of OSS as the first-choice treatment of OMT when possible. Close follow-up during the first 5 years is mandatory considering the risk of 8.3% of second events, especially in cases with risk factors.

Clinical, pathologic, and molecular features of inflammatory myofibroblastic tumors in children and adolescents.

BACKGROUND: Inflammatory myofibroblastic tumors (IMT) are rare, intermediate malignant tumors harboring frequent somatic molecular rearrangements. The management of IMT has not been standardized. METHODS: A retrospective multicenter study was conducted on all pediatric patients treated for IMT between 2000 and 2019. RESULTS: This series included 39 cases of IMT, with a median age at diagnosis of 7 years (range 20 days to 16 years). Tumor location included pelvis-abdomen (n = 16), thorax (n = 14), head and neck (n = 7), and limbs (n = 2). One patient had metastatic disease. Immunochemistry showed 21/39 (54%) anaplastic lymphoma kinase (ALK)-positive tumors. Somatic tyrosine kinase rearrangement was present in 31/36 (86%) of the tumors analyzed: 21 ALK, five ROS1, and five NTRK. Immediate surgery was performed in 24 patients (62%), with adjuvant therapy for three patients. Delayed surgery after neoadjuvant therapy was possible in 10 cases. Exclusive systemic therapy was delivered to four patients; one patient with orbital IMT was managed by watchful waiting. After a median follow-up of 33 months (range 5-124), eight (20%) recurrences/progressions occurred after surgery (seven after primary surgery and one after delayed surgery), after a median interval of 7 months (range 2-21), all in thoracic locations. The 3-year overall and disease-free survivals were 96.8% (95% CI: 79.2%-94.0%) and 77.4% (95% CI: 59.6%-88.1%), respectively. Relapses/progressions were more common in patients with a thoracic primary (p < .001) or after incomplete surgery with no adjuvant therapy (p = .027). CONCLUSION: Surgery is effective in most cases of pediatric IMT. Systematic analysis of tyrosine kinase rearrangement is recommended. When the tumor is deemed only partially resectable to preserve organs and function, neoadjuvant therapy may be proposed to allow adequate conservative surgery.

Prenatal-onset of congenital neuronal ceroid lipofuscinosis with a novel CTSD mutation.

BACKGROUND: Neuronal ceroid lipofuscinoses (NCLs) form a clinically and genetically heterogeneous group of inherited neurodegenerative disorders that share common neuropathological features. Although they are the first cause of neurodegenerative disorders in children, their congenital forms are rarely documented. They are classically due to mutations in the CTSD gene (the CLN10 disease). Affected newborns usually present severe microcephaly, seizures and respiratory failure leading to death within the first postnatal days or weeks. CASES: We report on two siblings, in which exome sequencing identified a novel homozygous CTSD variant. The first sib presented at birth with seizures, rapidly progressive postnatal microcephaly and visual deficiency related to retinal dysfunction. Progressive neurological deterioration leads to death at the age of 24 months. Cathepsin D activity was reduced in the cultured fibroblasts of this patient. The second sib, a fetus of 36 weeks of gestation, was delivered after pregnancy termination for brain abnormalities (in accordance with French Legislation) suggesting a recurrence of the disease. Fetal postmortem examination disclosed neuropathological features consistent with NCL. CONCLUSIONS: Congenital NCL related to CTSD mutations is a neuronal storage disorder that produces in the developing brain diffuse neurodegeneration and white matter atrophy resulting in a progressive and rapidly lethal microcephaly.

A kidney discard decision strategy based on zero-time histology analysis could lead to an unjustified increase in the organ turndown rate among ECD.

The utility of zero-time kidney biopsies (KB) in deciding to accept expanded criteria donor (ECD) kidneys remains controversial. However, zero-time histology is one of the main causes for discarding kidneys in the United States. In a single-centre study, we examined the utility and impact on outcome of the use of frozen section zero-time KB among ECD. Ninety-two zero-time KB were analysed for accept/discard decision between 2005 and 2015 among ECD. 53% of kidneys were rejected after zero-time KB analysis; there was no difference in individual clinical and biological data between accepted/rejected groups. However, histology of rejected kidneys showed more sclerotic glomeruli (20% vs. 8%; P < 0.001), increased interstitial fibrosis (1.25 ± 0.12 vs. 0.47 ± 0.09; P < 0.0001), more arteriosclerosis (2.14 ± 0.17 vs. 1.71 ± 0.11; P = 0.0032) and arteriolar hyalinosis (2.15 ± 0.12 vs. 1.55 ± 0.11; P = 0.0006). Using propensity score matching, we generated a group of 42 kidney allograft recipients who received a transplant matched for donor zero-time histology and clinical characteristics with donors whose kidneys were rejected. Interestingly, their 1- and 5-year graft survival and function were similar to the global cohort of ECD recipients. In conclusion, when performed, zero-time KB was a decisive element for kidney discard decision. However, adverse zero-time histology was not associated with poorer graft survival and kidney function among ECD.

Histological Severity Risk Factors Identification in Juvenile-Onset Recurrent Respiratory Papillomatosis: How Immunohistochemistry and AI Algorithms Can Help?

Juvenile-onset recurrent respiratory papillomatosis (JoRRP) is a condition characterized by the repeated growth of benign exophytic papilloma in the respiratory tract. The course of the disease remains unpredictable: some children experience minor symptoms, while others require multiple interventions due to florid growth. Our study aimed to identify histologic severity risk factors in patients with JoRRP. Forty-eight children from two French pediatric centers were included retrospectively. Criteria for a severe disease were: annual rate of surgical endoscopy ≥ 5, spread to the lung, carcinomatous transformation or death. We conducted a multi-stage study with image analysis. First, with Hematoxylin and eosin (HE) digital slides of papilloma, we searched for morphological patterns associated with a severe JoRRP using a deep-learning algorithm. Then, immunohistochemistry with antibody against p53 and p63 was performed on sections of FFPE samples of laryngeal papilloma obtained between 2008 and 2018. Immunostainings were quantified according to the staining intensity through two automated workflows: one using machine learning, the other using deep learning. Twenty-four patients had severe disease. For the HE analysis, no significative results were obtained with cross-validation. For immunostaining with anti-p63 antibody, we found similar results between the two image analysis methods. Using machine learning, we found 23.98% of stained nuclei for medium intensity for mild JoRRP vs. 36.1% for severe JoRRP (p = 0.041); and for medium and strong intensity together, 24.14% for mild JoRRP vs. 36.9% for severe JoRRP (p = 0.048). Using deep learning, we found 58.32% for mild JoRRP vs. 67.45% for severe JoRRP (p = 0.045) for medium and strong intensity together. Regarding p53, we did not find any significant difference in the number of nuclei stained between the two groups of patients. In conclusion, we highlighted that immunochemistry with the anti-p63 antibody is a potential biomarker to predict the severity of the JoRRP.

Dysregulation of the NRG1/ERBB pathway causes a developmental disorder with gastrointestinal dysmotility in humans.

Hirschsprung disease (HSCR) is the most frequent developmental anomaly of the enteric nervous system, with an incidence of 1 in 5000 live births. Chronic intestinal pseudo-obstruction (CIPO) is less frequent and classified as neurogenic or myogenic. Isolated HSCR has an oligogenic inheritance with RET as the major disease-causing gene, while CIPO is genetically heterogeneous, caused by mutations in smooth muscle-specific genes. Here, we describe a series of patients with developmental disorders including gastrointestinal dysmotility, and investigate the underlying molecular bases. Trio-exome sequencing led to the identification of biallelic variants in ERBB3 and ERBB2 in 8 individuals variably associating HSCR, CIPO, peripheral neuropathy, and arthrogryposis. Thorough gut histology revealed aganglionosis, hypoganglionosis, and intestinal smooth muscle abnormalities. The cell type-specific ErbB3 and ErbB2 function was further analyzed in mouse single-cell RNA sequencing data and in a conditional ErbB3-deficient mouse model, revealing a primary role for ERBB3 in enteric progenitors. The consequences of the identified variants were evaluated using quantitative real-time PCR (RT-qPCR) on patient-derived fibroblasts or immunoblot assays on Neuro-2a cells overexpressing WT or mutant proteins, revealing either decreased expression or altered phosphorylation of the mutant receptors. Our results demonstrate that dysregulation of ERBB3 or ERBB2 leads to a broad spectrum of developmental anomalies, including intestinal dysmotility.

Head and neck tumors in children and adolescents: Impact of a multidisciplinary tumor board.

INTRODUCTION: Cancer treatment in France is based on Multidisciplinary Tumor Board (MTB). In the Ile-de-France region (IDF), which includes 12 million inhabitants from Paris and the surrounding area, pediatric tumors of head and neck are discussed since 2013 in a dedicated Interregional Pediatric Multicentric MTB (IPMTB). The purpose of this study is to analyze the impact of the IDF head and neck IPMTB on the management of these tumors, 5 years after their implementation. MATERIALS AND METHODS: Retrospective study of all patient files presented in the IPMTB for a benign or malignant head-and-neck tumor, between 2013 and 2018. RESULTS: A total of 679 discussions were analyzed representing 428 patients. Median age was 7.5 years (range: 0-31 years). Malignant tumors represented 71% of cases, including 36% of rhabdomyosarcoma. Overall, 12% percent of the cases discussed came from centers outside of IDF. All meetings complied with multidisciplinary criteria required by French law. Proposals made during the IPMTB were followed in 86% of cases. Among the 251 proposals made by the referring teams prior to the IPMTB, 29% were secondarily modified after being discussed in the IPMTB. CONCLUSION: Thanks to their multidisciplinarity, high number of cases discussed and usual respect of their proposals, the IPMTB have made it possible to improve the coordination between all specialties involved in the patient's management, to apply the most recent and scientifically validated protocols, and to share the knowledge of different teams concerning the management of particularly rare tumors.

Analysis of enteric nervous system and intestinal epithelial barrier to predict complications in Hirschsprung's disease.

In Hirschsprung's disease (HSCR), postoperative course remains unpredictable. Our aim was to define predictive factors of the main postoperative complications: obstructive symptoms (OS) and Hirschsprung-associated enterocolitis (HAEC). In this prospective multicentre cohort study, samples of resected bowel were collected at time of surgery in 18 neonates with short-segment HSCR in tertiary care hospitals. OS and HAEC were noted during postoperative follow-up. We assessed the enteric nervous system and the intestinal epithelial barrier (IEB) in ganglionic segments by combining immunohistochemical, proteomic and transcriptomic approaches, with functional ex vivo analysis of motility and para/transcellular permeability. Ten HSCR patients presented postoperative complications (median follow-up 23.5 months): 6 OS, 4 HAEC (2 with OS), 2 diarrhoea (without OS/HAEC). Immunohistochemical analysis showed a significant 41% and 60% decrease in median number of nNOS-IR myenteric neurons per ganglion in HSCR with OS as compared to HSCR with HAEC/diarrhoea (without OS) and HSCR without complications (p = 0.0095; p = 0.002, respectively). Paracellular and transcellular permeability was significantly increased in HSCR with HAEC as compared to HSCR with OS/diarrhoea without HAEC (p = 0.016; p = 0.009) and HSCR without complications (p = 0.029; p = 0.017). This pilot study supports the hypothesis that modulating neuronal phenotype and enhancing IEB permeability may treat or prevent postoperative complications in HSCR.

Juvenile-Onset Recurrent Respiratory Papillomatosis Aggressiveness: In Situ Study of the Level of Transcription of HPV E6 and E7.

Juvenile-onset recurrent respiratory papillomatosis (JoRRP) is a condition related to HPV 6 and 11 infection which is characterized by the repeated growth of benign exophytic papilloma in the respiratory tract. Disease progression is unpredictable: some children experience minor symptoms, while others require multiple interventions due to florid growth. The aim of this study was to explore the biomarkers of JoRRP severity on a bicentric cohort of forty-eight children. We performed a CISH on the most recent sample of papilloma with a probe targeting the mRNA of the E6 and E7 genes of HPV 6 and 11 and an immunostaining with p16INK4a antibody. For each patient HPV RNA CISH staining was assessed semi-quantitatively to define two scores: 1+, defined as a low staining extent, and 2+, defined as a high staining extent. This series contained 19 patients with a score of 1+ and 29 with a score of 2+. Patients with a score of 2+ had a median of surgical excision (SE) per year that was twice that of patients with a score of 1+ (respectively 6.1 versus 2.8, p = 0.036). We found similar results with the median number of SE the first year. Regarding p16INK4a, all patients were negative. To conclude, HPV RNA CISH might be a biomarker which is predictive of disease aggressiveness in JoRRP, and might help in patient care management.

Cherubism as a systemic skeletal disease: evidence from an aggressive case.

BACKGROUND: Cherubism is a rare autosomal dominant genetic condition caused by mutations in the SH3BP2 gene. This disease is characterized by osteolysis of the jaws, with the bone replaced by soft tissue rich in fibroblasts and multinuclear giant cells. SH3BP2 is a ubiquitous adaptor protein yet the consequences of SH3BP2 mutation have so far been described as impacting only face. Cherubism mouse models have been generated and unlike human patients, the knock-in mice exhibit systemic bone loss together with a systemic inflammation. CASE PRESENTATION: In light of these observations, we decided to search for a systemic cherubism phenotype in a 6-year-old girl with an aggressive cherubism. We report here the first case of cherubism with systemic manifestations. Bone densitometry showed low overall bone density (total body Z-score = - 4.6 SD). Several markers of bone remodelling (CTx, BALP, P1NP) as well as inflammation (TNFα and IL-1) were elevated. A causative second-site mutation in other genes known to influence bone density was ruled out by sequencing a panel of such genes. CONCLUSIONS: If this systemic skeletal cherubism phenotype should be confirmed, it would simplify the treatment of severe cherubism patients and allay reservations about applying a systemic treatment such as those recently published (tacrolimus or imatinib) to a disease heretofore believed to be localised to the jaws.

Pheochromocytoma and Paraganglioma in Children and Adolescents: Experience of the French Society of Pediatric Oncology (SFCE).

PURPOSE: The purpose of this work is to assess the clinical outcome of pediatric patients diagnosed with pheochromocytoma and paraganglioma (PPGL) detected in France since 2000. METHODS: A retrospective multicenter study was conducted that included all patients younger than 18 years with PPGL diagnosed in France between 2000 and 2016. Patients were identified from 4 different sources: the National Registry of Childhood Solid Tumors, the French Pediatric Rare Tumors Database, the French registry of succinate dehydrogenase (SDH)-related hereditary paraganglioma, and the nationwide TenGen network. RESULTS: Among 113 eligible patients, 81 children with available data were enrolled (41 with adrenal and 40 with extra-adrenal PPGL). At diagnosis, 11 had synchronous metastases. After a median follow-up of 53 months, 27 patients experienced a new event (n = 7 second PPGL, n = 1 second paraganglioma [PGL], n = 8 local recurrences, n = 10 metastatic relapses, n = 1 new tumor) and 2 patients died of their disease. The 3- and 10-year event-free survival rates were 80% (71%-90%) and 39% (20%-57%),respectively, whereas the overall survival rate was 97% (93%-100%)at 3 and 10 years. A germline mutation in one PPGL-susceptibility gene was identified in 53 of the 68 (77%) patients who underwent genetic testing (SDHB [n = 25], VHL [n = 21], RET [n = 2], HIF2A [n = 2], SDHC [n = 1], SDHD [n = 1], NF1 [n = 1]). Incomplete resection and synchronous metastases were associated with higher risk of events (P = .011, P = .004), but presence of a germline mutation was not (P = .11). CONCLUSIONS: Most pediatric PPGLs are associated with germline mutations and require specific follow-up because of the high risk of tumor recurrence.

Bi-allelic Variations of SMO in Humans Cause a Broad Spectrum of Developmental Anomalies Due to Abnormal Hedgehog Signaling.

The evolutionarily conserved hedgehog (Hh) pathway is essential for organogenesis and plays critical roles in postnatal tissue maintenance and renewal. A unique feature of the vertebrate Hh pathway is that signal transduction requires the primary cilium (PC) where major pathway components are dynamically enriched. These factors include smoothened (SMO) and patched, which constitute the core reception system for sonic hedgehog (SHH) as well as GLI transcription factors, the key mediators of the pathway. Here, we report bi-allelic loss-of-function variations in SMO in seven individuals from five independent families; these variations cause a wide phenotypic spectrum of developmental anomalies affecting the brain (hypothalamic hamartoma and microcephaly), heart (atrioventricular septal defect), skeleton (postaxial polydactyly, narrow chest, and shortening of long bones), and enteric nervous system (aganglionosis). Cells derived from affected individuals showed normal ciliogenesis but severely altered Hh-signal transduction as a result of either altered PC trafficking or abnormal activation of the pathway downstream of SMO. In addition, Hh-independent GLI2 accumulation at the PC tip in cells from the affected individuals suggests a potential function of SMO in regulating basal ciliary trafficking of GLI2 when the pathway is off. Thus, loss of SMO function results in abnormal PC dynamics of key components of the Hh signaling pathway and leads to a large continuum of malformations in humans.