Indications and results of diagnostic biopsy in pediatric renal tumors: A retrospective analysis of 317 patients with critical review of SIOP guidelines.

OBJECTIVES: According to the Renal Tumor Study Group (RTSG) of the International Society of Paediatric Oncology (SIOP), diagnostic biopsy of renal tumors prior to neoadjuvant chemotherapy is not mandatory unless the presentation is atypical for a Wilms tumor (WT). This study addresses the relevance of this strategy as well as the accuracy and safety of image-guided needle biopsy. METHODS: Clinical, radiological, and pathological data from 317 children (141 males/176 females, mean age: 4 years, range, 0-17.6) consecutively treated in one SIOP-affiliated institution were retrospectively analyzed. RESULTS: Presumptive chemotherapy for WT was decided for 182 patients (57% of the cohort), 24 (8%) were operated upfront, and 111 (35%) were biopsied at diagnosis. A non-WT was confirmed after surgery in 5/182 (3%), 11/24 (46%), and 28/111 (25%), respectively. Age at diagnosis was the most commonly (46%) used criterion to go for biopsy but a nine-year threshold should be retrospectively considered more relevant. Tumor volumes of clear cell sarcoma of the kidney and WT were significantly higher than those of other tumors (P = 0.002). The agreement between core-needle biopsy (CNB) and final histology was 99%. No significant morbidity was associated with CNB. CONCLUSION: The use of SIOP criteria to identify patients eligible for presumptive WT neoadjuvant chemotherapy or upfront surgery avoided biopsy in 65% of children and led to a 97% rate of appropriate preoperative chemotherapy. Image-guided CNB is a safe and accurate diagnostic procedure. The relevance of SIOP biopsy criteria might be improved by using an older age threshold (9 years instead of 6 years) and by adding initial tumor volume.

Constitutional mismatch repair deficiency syndrome: clinical description in a French cohort.

BACKGROUND: Constitutional mismatch repair deficiency (CMMRD) syndrome is a childhood cancer predisposition syndrome involving biallelic germline mutations of MMR genes, poorly recognised by clinicians so far. METHODS: Retrospective review of all 31 patients with CMMRD diagnosed in French genetics laboratories in order to describe the characteristics, treatment and outcome of the malignancies and biological diagnostic data. RESULTS: 67 tumours were diagnosed in 31 patients, 25 (37%) Lynch syndrome-associated malignancies, 22 (33%) brain tumours, 17 (25%) haematological malignancies and 3 (5%) sarcomas. The median age of onset of the first tumour was 6.9 years (1.2-33.5). Overall, 22 patients died, 9 (41%) due to the primary tumour. Median survival after the diagnosis of the primary tumour was 27 months (0.26-213.2). Failure rate seemed to be higher than expected especially for T-cell non-Hodgkin's lymphoma (progression/relapse in 6/12 patients). A familial history of Lynch syndrome was identified in 6/23 families, and consanguinity in 9/23 families. PMS2 mutations (n=18) were more frequent than other mutations (MSH6 (n=6), MLH1 (n=4) and MSH2 (n=3)). CONCLUSIONS: In conclusion, this unselected series of patients confirms the extreme severity of this syndrome with a high mortality rate mostly related to multiple childhood cancers, and highlights the need for its early detection in order to adapt treatment and surveillance.

Guidelines for surveillance of individuals with constitutional mismatch repair-deficiency proposed by the European Consortium "Care for CMMR-D" (C4CMMR-D).

Lynch syndrome (LS) is an autosomal dominant disorder caused by a defect in one of the DNA mismatch repair genes: MLH1, MSH2, MSH6 and PMS2. In the last 15 years, an increasing number of patients have been described with biallelic mismatch repair gene mutations causing a syndrome referred to as 'constitutional mismatch repair-deficiency' (CMMR-D). The spectrum of cancers observed in this syndrome differs from that found in LS, as about half develop brain tumours, around half develop digestive tract cancers and a third develop haematological malignancies. Brain tumours and haematological malignancies are mainly diagnosed in the first decade of life, and colorectal cancer (CRC) and small bowel cancer in the second and third decades of life. Surveillance for CRC in patients with LS is very effective. Therefore, an important question is whether surveillance for the most common CMMR-D-associated cancers will also be effective. Recently, a new European consortium was established with the aim of improving care for patients with CMMR-D. At a workshop of this group held in Paris in June 2013, one of the issues addressed was the development of surveillance guidelines. In 1968, criteria were proposed by WHO that should be met prior to the implementation of screening programmes. These criteria were used to assess surveillance in CMMR-D. The evaluation showed that surveillance for CRC is the only part of the programme that largely complies with the WHO criteria. The values of all other suggested screening protocols are unknown. In particular, it is questionable whether surveillance for haematological malignancies improves the already favourable outcome for patients with these tumours. Based on the available knowledge and the discussions at the workshop, the European consortium proposed a surveillance protocol. Prospective collection of all results of the surveillance is needed to evaluate the effectiveness of the programme.

Malformations, genetic abnormalities, and Wilms tumor.

BACKGROUND: Wilms Tumor (WT) can occur in association with tumor predisposition syndromes and/or with clinical malformations. These associations have not been fully characterized at a clinical and molecular genetic level. This study aims to describe clinical malformations, genetic abnormalities, and tumor predisposition syndromes in patients with WT and to propose guidelines regarding indications for clinical and molecular genetic explorations. PROCEDURE: This retrospective study analyzed clinical abnormalities and predisposition syndromes among 295 patients treated for WT between 1986 and 2009 in a single pediatric oncological center. RESULTS: Clinically identified malformations and predisposition syndromes were observed in 52/295 patients (17.6%). Genetically proven tumor predisposition syndromes (n = 14) frequently observed were syndromes associated with alterations of the chromosome WT1 region such as WAGR (n = 6) and Denys-Drash syndromes (n = 3), syndromes associated with alterations of the WT2 region (Beckwith-Wiedeman syndrome, n = 3), and Fanconi anemia (n = 2). Hemihypertrophy and genito-urinary malformations (n = 12 and n = 16, respectively) were the most frequently identified malformations. Other different syndromes or malformations (n = 10) were less frequent. Median age of WT diagnosis was significantly earlier for children with malformations than those without (27 months vs. 37 months, P = 0.0009). There was no significant difference in terms of 5-year EFS and OS between WT patients without or with malformations. CONCLUSIONS: The frequency of malformations observed in patients with WT underline the need of genetic counseling and molecular genetic explorations for a better follow-up of these patients, with a frequently good outcome. A decisional tree, based on clinical observations of patients with WT, is proposed to guide clinicians for further molecular genetic explorations.

Imaging Features with Histopathologic Correlation of CNS High-Grade Neuroepithelial Tumors with a BCOR Internal Tandem Duplication.

BACKGROUND AND PURPOSE: A new brain tumor entity occurring in early childhood characterized by a somatic BCL6 corepressor gene internal tandem duplication was recently described. The aim of this study was to describe the radiologic pattern of these tumors and correlate this pattern with histopathologic findings. MATERIALS AND METHODS: This retrospective, noninterventional study included 10 children diagnosed with a CNS tumor, either by ribonucleic acid-sequencing analysis or deoxyribonucleic acid methylation analysis. Clinical, radiologic, and histopathologic data were collected. A neuropathologist reviewed 9 tumor samples. Preoperative images were analyzed in consensus by 7 pediatric radiologists. RESULTS: All tumors were relatively large (range, 4.7-9.2 cm) intra-axial peripheral masses with well-defined borders and no peritumoral edema. All tumors showed mild and heterogeneous enhancement and marked restriction on DWI of the solid portions. Perfusion imaging showed a relatively lower CBF in the tumor than in the adjacent normal parenchyma. Nine of 10 tumors showed areas of necrosis, with the presence of hemorrhage in 8/10 and calcifications in 4/7. Large intratumoral macroscopic veins were observed in 9/10 patients. No intracranial or spinal leptomeningeal dissemination was noted at diagnosis. CONCLUSIONS: CNS tumors with a BCL6 corepressor gene internal tandem duplication present as large intra-axial peripheral masses with well-defined borders, no edema, restricted diffusion, weak contrast enhancement, frequent central necrosis, hemorrhage and calcifications, intratumoral veins, and no leptomeningeal dissemination at the time of diagnosis. Knowledge of these imaging characteristics may aid in histologic, genomic, and molecular profiling of brain tumors in young children.

[Medulloblastomas: review]. / Les médulloblastomes: revue générale.

INTRODUCTION: The term of "medulloblastoma" refers to cerebellar tumors belonging to the family of primitive neuro-ectodermic tumors (PNET). Medulloblastomas represent 40% of cerebellar tumors, 15 to 20% of brain tumors and the first cause of malignant brain tumors in childhood. Seventy to 80% of cases are diagnosed in children versus 20 to 30% in adults. UPDATED KNOWLEDGE: Diagnosis is based on clinical and radiological exams, and proved on pathological analysis in association with molecular biology. Treatment comprises surgery, craniospinal radiotherapy except for children under five years of age and chemotherapy according to age and high-risk criteria. Medulloblastoma is a rare case of a central nervous system tumor which is radio- and chemo-sensitive. Treatment goals are, on one hand, to improve the survival rates and, on the other hand, to avoid late neurocognitive, neuroendocrine and orthopedic side effects related to radiation therapy, notably in children. The prognosis is relatively good, with a five year survival rate over 75% after complete resection of a localized tumor although sequelae may still compromise outcome. PERSPECTIVES AND CONCLUSION: Management of patients with medulloblastoma implies a multidisciplinary approach combining the contributions of neurosurgery, neuroradiology, pediatric oncology, neuro-oncology and radiotherapy teams.

Current recommendations for clinical surveillance and genetic testing in rhabdoid tumor predisposition: a report from the SIOPE Host Genome Working Group.

The rhabdoid tumor (RT) predisposition syndromes 1 and 2 (RTPS1 and 2) are rare genetic conditions rendering young children vulnerable to an increased risk of RT, malignant neoplasms affecting the kidney, miscellaneous soft-part tissues, the liver and the central nervous system (Atypical Teratoid Rhabdoid Tumors, ATRT). Both, RTPS1&2 are due to pathogenic variants (PV) in genes encoding constituents of the BAF chromatin remodeling complex, i.e. SMARCB1 (RTPS1) and SMARCA4 (RTPS2). In contrast to other genetic disorders related to PVs in SMARCB1 and SMARCA4 such as Coffin-Siris Syndrome, RTPS1&2 are characterized by a predominance of truncating PVs, terminating transcription thus explaining a specific cancer risk. The penetrance of RTPS1 early in life is high and associated with a poor survival. However, few unaffected carriers may be encountered. Beyond RT, the tumor spectrum may be larger than initially suspected, and cancer surveillance offered to unaffected carriers (siblings or parents) and long-term survivors of RT is still a matter of discussion. RTPS2 exposes female carriers to an ill-defined risk of small cell carcinoma of the ovaries, hypercalcemic type (SCCOHT), which may appear in prepubertal females. RT surveillance protocols for these rare families have not been established. To address unresolved issues in the care of individuals with RTPS and to propose appropriate surveillance guidelines in childhood, the SIOPe Host Genome working group invited pediatric oncologists and geneticists to contribute to an expert meeting. The current manuscript summarizes conclusions of the panel discussion, including consented statements as well as non-evidence-based proposals for validation in the future.

Focal Areas of High Signal Intensity in Children with Neurofibromatosis Type 1: Expected Evolution on MRI.

BACKGROUND AND PURPOSE: Focal areas of high signal intensity are T2WI/T2-FLAIR hyperintensities frequently found on MR imaging of children diagnosed with neurofibromatosis type 1, often thought to regress spontaneously during adolescence or puberty. Due to the risk of tumor in this population, some focal areas of high signal intensity may pose diagnostic problems. The objective of this study was to assess the characteristics and temporal evolution of focal areas of high signal intensity in children with neurofibromatosis type 1 using long-term follow-up with MR imaging. MATERIALS AND METHODS: We retrospectively examined the MRIs of children diagnosed with neurofibromatosis type 1 using the National Institutes of Health Consensus Criteria (1987), with imaging follow-up of at least 4 years. We recorded the number, size, and surface area of focal areas of high signal intensity according to their anatomic distribution on T2WI/T2-FLAIR sequences. A generalized mixed model was used to analyze the evolution of focal areas of high signal intensity according to age, and separate analyses were performed for girls and boys. RESULTS: Thirty-nine patients (ie, 285 MR images) with a median follow-up of 7 years were analyzed. Focal areas of high signal intensity were found in 100% of patients, preferentially in the infratentorial white matter (35% cerebellum, 30% brain stem) and in the capsular lenticular region (22%). They measured 15 mm in 95% of cases. They appeared from the age of 1 year; increased in number, size, and surface area to a peak at the age of 7; and then spontaneously regressed by 17 years of age, similarly in girls and boys. CONCLUSIONS: Focal areas of high signal intensity are mostly small (<15 mm) abnormalities in the posterior fossa or capsular lenticular region. Our results suggest that the evolution of focal areas of high signal intensity is not related to puberty with a peak at the age of 7 years. Knowledge of the predictive evolution of focal areas of high signal intensity is essential in the follow-up of children with neurofibromatosis type 1.

[Rhadboid tumours: hSNF/INI1 deficient cancers of early childhood with aggressive behaviour]. / Les tumeurs rhabdoïdes : des tumeurs hSNF5/INI1-déficientes précoces et agressives.

Rhabdoid tumours are rare aggressive tumours of infancy. The definition classically relies on a characteristic morphology and the inactivation of the hSNF5/INI1 tumour suppressor gene. This entity includes central nervous system tumours (ATRT), renal tumours (RTK) and soft-part tumours. Their rarity and morphological pleomorphism make the diagnosis often challenging. However, the recently introduced immunohistochemistry with anti-INI1 (anti-SMARCB1) antibody is a very useful diagnostic tool. Deletions at the 22q11.2 locus and mutations in hSNF5/INI1 sequence must be investigated in order to confirm the diagnosis and to give insights on a presumable germline mutation. Indeed, a predisposition may be found in up to 30% of cases. The treatment is based on aggressive chemotherapy, surgery and irradiation. The prognosis remains poor and the survival rate is below 30%, whatever the anatomic location. Understanding the role of hSNF5/INI1 within the SWI-SNF complex for the epigenetic regulation of transcription might drive the future targeted therapies.

[The alliance of the parent, child and the nurse to challenge medical error]. / L'alliance parents-enfant-soignants à l'épreuve de l'erreur médicale.

A group composed of parents, nurses, and physicians involved in pediatric cancerology has reflected on medical errors within the Espace Éthique de l'Assistance publique-Hôpitaux de Paris. Based on narratives and qualitative analysis of histories and testimonies, this discussion aimed at exploring the causes, circumstances, and impacts of medical errors on the relations between these individuals. The study demonstrated that some circumstances actually promote medical errors, such as hard working conditions, mistrust, unreliable control procedures, not listening to parents, and caring for children in extreme situations of pain and suffering. Errors almost always result from the accumulation of several shortcomings. The tensions raised by a medical error can be overcome, provided that parents and caregivers trust each other from the onset of disease and that the medical errors are disclosed in a sincere way, whatever the medical consequences. The feelings raised by the painful experience of a medical error do not solely depend on the severity of the consequences, since seemingly benign errors may lead to long-term trauma, whereas severe errors, even those leading to death, do not necessarily breach trust. The keyword here is permanent vigilance. The capacity of caregivers to question their practice, from both a technical and ethical point of view, will determine their ability to learn from an error for the future. The depth and quality of this questioning, in the best of times encouraged by the institution, may also help children affected by a medical error and their family to move forward in their personal history, beyond such painful experiences.

In neuroblastic tumours, Schwann cells do not harbour the genetic alterations of neuroblasts but may nevertheless share the same clonal origin.

Neuroblastic tumours are composed of variable proportions of neuroblasts and Schwann cells. Whether both components share a common neoplastic origin is highly debated and discrepant results have been reported about the presence of tumour-related genetic alterations in Schwann cells. We have used X-methylation analysis and array-CGH to investigate contiguous Schwannian and neuroblastic areas in tumours with a nodular pattern. A skewed X inactivation was observed in four out of five stromal components. Interestingly, in these four cases, the X-inactivation profiles of the neuroblastic components were identical to the matched stromal areas. However, whereas all neuroblastic areas displayed chromosomal imbalances, no alteration was found in any Schwann cell components. Similarly, no alteration was observed in a series of 19 tumours with a single stroma-rich component, which occasionally exhibited a skewed X-inactivation pattern (3/17 informative tumours). Altogether, this indicates that most stroma-rich tumours display a polyclonal proliferation and that Schwann cells do not derive from neuroblasts. However, in tumours with both stroma-rich and -poor components, our results suggest that cells from both areas share a common progenitor.

hSNF5/INI1-deficient tumours and rhabdoid tumours are convergent but not fully overlapping entities.

Rhabdoid tumours (RTs) are rare but highly aggressive tumours of childhood. Their rarity and their miscellaneous locations make the diagnosis particularly challenging for pathologists. Central nervous system and peripheral RTs have been associated with biallelic inactivation of the hSNF5/INI1/SMARCB1 (hSNF5/INI1) tumour suppressor gene. Immunohistochemistry (IHC) with a monoclonal anti-hSNF5/INI1 antibody has recently been proposed as an efficient diagnostic tool for RTs. We have conducted a retrospective study of 55 tumours referred to our institution with a suspicion of RT. This analysis included pathological review, IHC with anti-hSNF5/INI1 antibody, and molecular investigation using quantitative DNA fluorescent analysis and sequencing of the nine exons of hSNF5/INI1. The molecular lesion could be detected in 37 of the 39 cases exhibiting negative staining for hSNF5/INI1. In the two discrepant cases, the lack of detection of genetic abnormality was probably owing to the presence of a high number of non-tumour cells in the samples. This indicates that hSNF5/INI1 IHC is very sensitive and highly specific for the detection of hSNF5/INI1 loss-of-function. Among the 38 cases with typical RT histological features, six failed to exhibit hSNF5/INI1 mutation and stained positive for hSNF5/INI1. This strongly supports the evidence of a second genetic locus, distinct from hSNF5/INI1, associated with RT. Conversely, seven tumours with histological features poorly compatible with RT stained negative for hSNF5/INI1; they nevertheless exhibited an age of onset and a clinical behaviour similar to RT. This suggests that hSNF5/INI1 inactivation is not strictly limited to typical RT but characterizes a wider family of hSNF5/INI1-deficient tumours. Consequently, we believe that anti-hSNF5/INI1 IHC should be performed widely, even when the pathological characteristics are not typical. The molecular investigation should be performed in infants when a rhabdoid predisposition syndrome is suspected.