Imaging of Wilms tumor: an update

Staging and Restaging Pediatric Abdominal and Pelvic Tumors: A Practical Guide

The most common abdominal malignancies diagnosed in the pediatric population include neuroblastoma, Wilms tumor, hepatoblastoma, lymphoma, germ cell tumor, and rhabdomyosarcoma. There are distinctive imaging findings and patterns of spread for each of these tumors that radiologists must know for diagnosis and staging and for monitoring the patient's response to treatment. The multidisciplinary treatment group that includes oncologists, surgeons, and radiation oncologists relies heavily on imaging evaluation to identify the best treatment course and prognostication of imaging findings, such as the image-defined risk factors for neuroblastomas, the PRETreatment EXtent of Disease staging system for hepatoblastoma, and the Ann Arbor staging system for lymphomas. It is imperative for radiologists to be able to correctly indicate the best imaging methods for diagnosis, staging, and restaging of each of these most prevalent tumors to avoid inconclusive or unnecessary examinations. The authors review in a practical manner the most updated key points in diagnosing and staging disease and assessing response to treatment of the most common pediatric abdominal tumors. ©RSNA, 2024 Supplemental material is available for this article.

LINC00858 facilitates the malignant development of Wilms' Tumor by targeting miR-653-5p

BACKGROUND

To uncover the clinical significance of LINC00858 in the development of Wilms' Tumor and the potential molecular mechanism.

METHODS

LINC00858 levels in Wilms' Tumor species and cell lines were determined by quantitative real-time polymerase chain reaction (qRT-PCR). The clinical significance of LINC00858 in influencing pathological features and prognosis in patients with Wilms' Tumor was analyzed. Proliferative and migratory changes in Wilms' Tumor cells with LINC00858 knockdown were assessed. The downstream gene of LINC00858 was verified by luciferase assay, and its involvement in the development of Wilms' Tumor was further explored.

RESULTS

LINC00858 was highly expressed in Wilms' Tumor tissues and cell lines. High level of LINC00858 was correlated to high rate of lymphatic metastasis and poor prognosis in patients with Wilms' Tumor. Knockdown of LINC00858 suppressed proliferative and migratory potentials in HFWT and 17-94 cells. MiR-653-5p was targeted by LINC00858. It was lowly expressed in Wilms' Tumor tissues and negatively regulated by LINC00858. Knockdown of miR-653-5p partially abolished the regulatory effects of LINC00858 on proliferative and migratory potentials in Wilms' Tumor cells.

CONCLUSIONS

LINC00858 is highly expressed in Wilms' Tumor species and correlated to lymphatic metastasis rate and overall survival in patients with Wilms' Tumor. Knockdown of LINC00858 suppresses Wilms' Tumor cells to proliferate and migrate via targeting miR-653-3p.

Contrast-enhanced ultrasound for differentiating benign from malignant focal solid renal lesions in pediatric patients

The contrast-enhanced ultrasound (CEUS) has been mainly applied to adults to differentiate benign and malignant renal lesions, however, the characteristics of CEUS in pediatric has not been as well studied as in adults. In the present work, the eligible pediatric patients who underwent renal CEUS between March 2016 and February 2023 were retrospectively analyzed. It included 20 lesions (median diameter, 8.4 cm; range, 1.8-18.0 cm) from 20 patients (median age, 28.0 months; range, 3.0-212.0 months; 9 boys) in malignant group and 5 lesions (median diameter, 3.8 cm; range, 1.3-7.5 cm) from 5 patients (median age, 25.0 months; range, 0.7-216.0 months; 2 boys) in benign group. The diagnostic performance was assessed. Nonparametric and Chi-square tests were performed. With hyperenhancement plus wash-out, CEUS showed a sensitivity of 95.0% [95% confidence interval (CI): 75.1%, 99.9%], a specificity of 80.0% (CI: 28.4%, 99.5%), a positive predictive value of 95.0% (CI: 75.1%, 99.9%) and a negative predictive value of 80.0% (CI: 28.4%, 99.5%). It suggested that CEUS is a valuable technique for identifying between malignant and benign renal lesions in children.

miRNAs Role in Wilms tumor pathogenesis: Signaling pathways interplay

Wilms' tumors (WTs) are the most common type of kidney tumor in children, and a negative outlook is generally associated with widespread anaplastic. MicroRNAs (miRNAs) are crucial in the development of WT by regulating the expression of specific genes. There is an increasing amount of research that connects the dysregulation of miRNAs to the development of various renal illnesses. The conditions encompassed are renal fibrosis, renal cancers, and chronic and polycystic kidney disease. Dysregulation of several important miRNAs, either oncogenic or tumor-suppressing, has been found in WT. The present state of knowledge on the involvement of dysregulated miRNAs in the progression of WT is summarized in this review.

Case Report: Autosomal dominant polycystic kidney disease and Wilms' tumor in infancy and childhood

Background

Autosomal dominant polycystic kidney disease (ADPKD) is rare but one of the most common inherited kidney diseases. Normal kidney function is maintained until adulthood in most patients. About 7 in 10 patients with ADPKD develop kidney failure in the latter half of their fifth decade of life. Wilms' tumor, or nephroblastoma, is the most common malignant tumor stemming from kidney cells in the pediatric age group. This type of tumor is the most frequently occurring kidney malignancy in children between the ages of 0 and 5 years. The exact cause of Wilms' tumor is unknown, though about 10% of cases have a genetic predisposition. Wilms' tumor is one of the most successfully treated childhood oncological diseases. Overall, the 5-year survival rates were approximately 90% in both the National Wilms Tumor Study (NWTS) and Paediatric Oncology SIOP studies, showing similar results.

Case presentation

We report a case of a girl diagnosed with autosomal polycystic kidney disease, who subsequently developed Wilms' tumor and underwent successful treatment with chemotherapy. Polycystic kidney disease was suspected in the fetus during prenatal ultrasound and confirmed after birth with ultrasound and genetic testing. The Wilms tumor was an accidental finding during abdominal MRI at the age of 2 years old to rule out liver pathology.

Conclusion

Reports on whether a diagnosis of ADPKD is a risk factor for malignancy are conflicting. In this particular case, Wilms' tumor is present in the background of polycystic kidney disease and was timely diagnosed by an incidental MRI.

[Renal tumors in children and adolescents]

CLINICAL/METHODOLOGICAL ISSUE

Diagnosis and therapy of renal tumors in children and adolescents are standardized by study protocols from major international societies. Imaging plays a central role, and in Europe patients between the ages of 6 months and 14 years with renal tumors are referred to neoadjuvant chemotherapy without histological confirmation according to the study protocol due to the frequency of Wilms tumor.

STANDARD RADIOLOGIC METHODS

Ultrasound is used worldwide as the primary investigative procedure for suspected renal tumors. In Europe, magnetic resonance imaging (MRI) has become established for more advanced diagnosis. In addition to differential diagnosis, staging is crucial for therapy. According to current protocol, this includes computed tomography (CT) of the thorax for the evaluation of pulmonary metastases.

METHODOLOGICAL INNOVATIONS

Diffusion-weighted MRI provides promising results for the differentiation of nephroblastoma subtypes in addition to improved detectability of tumor foci. However, sufficient evidence is lacking.

PERFORMANCE

Differentiation of Wilms tumor from the highly malignant non-Wilm tumors, such as malignant rhabdoid tumor and clear cell sarcoma of the kidney, remains inconclusive based on imaging alone. Differential diagnosis is, therefore, based on morphologic and epidemiologic criteria.

ASSESSMENT

The high degree of standardization in the diagnosis and treatment of renal tumors in children and adolescents has led to a significant improvement in prognosis. Overall survival of patients with Wilms tumor is currently over 90%.

Wilms tumor in horseshoe kidney with extensive vascular thrombosis: A case report

INTRODUCTION AND IMPORTANCE

Wilms tumor (WT), a prevalent pediatric renal malignancy (7 %), frequently intertwines with genitourinary anomalies. This unique report presents a case of WT combined with horseshoe Kidney and an extending atrial thrombus, emphasizing critical management considerations.

CASE PRESENTATION

A 3-year-old boy, experiencing flank pain and weight loss, manifested a WT linked to horseshoe Kidney, accompanied by an atrial thrombus. Neoadjuvant chemotherapy downsized the tumor and thrombus, enabling successful surgical intervention. Post-surgery, 27 weeks of adjuvant chemotherapy were administered. Over three years, follow-up exhibited renal recovery, no recurrence, and clear CT scans.

DISCUSSION

Prompt identification, precise imaging (via CT angiography), and multidisciplinary care are pivotal for managing WT in horseshoe Kidney cases. Preoperative chemotherapy notably reduced tumor and thrombus sizes, enhancing surgical feasibility. Long-term vigilance is essential for recurrence and treatment-related complications.

CONCLUSION

Effectively managing WT in horseshoe Kidneys demands timely recognition, meticulous imaging, and collaborative management. Successful outcomes highlight preoperative chemotherapy's benefits and underscore extended monitoring's significance in confirming sustained recovery.

Health-Related Quality of Life and Mental Health of Children with Embryonal Abdominal Tumors

(1) Background: Embryonal abdominal tumors are one of the most common entities of solid childhood cancer. The present study investigates the Health-Related Quality of Life (HRQoL) and the mental health of children to obtain a comprehensive picture of their health status and uncover a possible gap in healthcare. (2) Methods: The sample consisted of 54 children who were treated for embryonal abdominal tumors and a control group of 46 children who received uncomplicated outpatient surgery. The HRQoL and the mental health were assessed by the parent proxy reports of the questionnaires Pediatric Quality of Life Inventory (PedsQL) and Strengths and Difficulties Questionnaire (SDQ). (3) Results: Children with embryonal abdominal tumors showed significantly lower HRQoL and mental health values compared to the norm data. The index group showed lower values in the social subscales of HRQoL and mental health compared to the control group. (4) Conclusions: Embryonal abdominal tumors affect the well-being of children. There is still a gap in healthcare due to children's HRQoL and mental health, especially regarding social development. It is essential to further advance the psychological care of children and improve their chances to develop social relationships.

Critical elements of radical nephroureterectomy for pediatric unilateral renal tumor

Children with renal masses require surgical management to provide accurate surgical staging and skilled resection of the tumor. This document includes evidence-based recommendations for pediatric surgeons regarding the resection, staging, and proper nodal basin evaluation.

Circulating microRNA profiles in Wilms tumour (WT): A systematic review and meta-analysis of diagnostic test accuracy

Background

Wilms tumour (WT) is caused by aberrant embryonic kidney development and associated with dysregulated expression of short, non-protein-coding RNAs termed microRNAs (miRNAs). At present, there is no reliable circulating biomarker of WT, and this remains an urgent unmet clinical need. Such biomarkers may assist diagnosis, subtyping/prognostication, and disease-monitoring. Here, we established the list of dysregulated circulating miRNAs in WT from the existing published literature.

Methods

Regardless of publication date, PubMed, Scopus, Web-of-Science, and Wiley online library databases were searched for English/French studies on WT circulating miRNAs. The PRISMA-compliant search was registered in PROSPERO. The QUADAS tool measured retained article quality. The meta-analysis assessed the sensitivity and specificity of miRNAs for WT diagnosis.

Results

Qualitative analysis included 280 samples (172 WT patients; 108 healthy controls) from five of 450 published articles. The study uncovered 301 dysregulated miRNAs (144 up-regulated, 143 down-regulated, 14 conflicting). The pooled sensitivity, specificity, and AUC of the 49 significantly dysregulated microRNAs from two studies was 0.67 [0.62; 0.73], 0.95 [0.92; 0.96] and 0.77 [0.73; 0.81] respectively, indicating a stronger diagnostic potential for WT.

Conclusions

Circulating miRNAs show promise for WT diagnosis and prognosis. More research is needed to confirm these findings and determine associations with tumour stage/subtype.

Prospero registration number

CRD42022301597.

Update on the Role of Imaging in Staging of Common Pediatric Abdominal Tumors

Neuroblastoma, Wilms tumor, and hepatoblastoma are the most common pediatric abdominal malignancies. Management of these diseases is a multidisciplinary process that continues to evolve based on the results of international collaborative trials and advances in understanding of tumor biology. Each of these tumors has unique characteristics and behavior which are reflected in their respective staging systems. It is important for clinicians involved in the care of children with abdominal malignancies to be familiar with current staging guidelines and imaging recommendations. This article reviews the current role of imaging in the management of these common pediatric abdominal malignancies, with emphasis on initial staging.

Imaging of pediatric renal tumors: A COG Diagnostic Imaging Committee/SPR Oncology Committee White Paper focused on Wilms tumor and nephrogenic rests

Malignant renal tumors account for approximately 6% of pediatric malignancies, with Wilms tumor (WT) representing approximately 90% of pediatric renal tumors. This paper provides consensus-based imaging guidelines for the initial evaluation of a child with suspected WT and follow-up during and after therapy co-developed by the Children's Oncology Group (COG) Diagnostic Imaging and Society for Pediatric Radiology (SPR) oncology committees. The guidelines for Wilms Tumor Imaging in the Society of International Pediatric Oncology (SIOP) are briefly discussed to highlight some of the differences in imaging approach.

Comparison of the different imaging modalities used to image pediatric oncology patients: A COG diagnostic imaging committee/SPR oncology committee white paper

Diagnostic imaging is essential in the diagnosis and management, including surveillance, of known or suspected cancer in children. The independent and combined roles of the various modalities, consisting of radiography, fluoroscopy, ultrasonography (US), computed tomography (CT), magnetic resonance imaging (MRI), and nuclear medicine (NM), are both prescribed through protocols but also function in caring for complications that may occur during or subsequent to treatment such as infection, bleeding, or organ compromise. Use of a specific imaging modality may be based on situational circumstances such as a brain CT or MR for a new onset seizure, chest CT for respiratory signs or symptoms, or US for gross hematuria. However, in many situations, there are competing choices that do not easily lend themselves to a formulaic approach as options; these situations depend on the contributions of a variety of factors based on a combination of the clinical scenario and the strengths and limitations of the imaging modalities. Therefore, an improved understanding of the potential influence of the imaging decision pathways in pediatric cancer care can come from comparison among the individual diagnostic imaging modalities. The purpose of the following material to is to provide such a comparison. To do this, pediatric imaging content experts for the individual modalities of radiography and fluoroscopy, US, CT, MRI, and NM will discuss the individual modality strengths and limitations.

Characterization of Continuous Transcriptional Heterogeneity in High-Risk Blastemal-Type Wilms' Tumors Using Unsupervised Machine Learning

Wilms' tumors are pediatric malignancies that are thought to arise from faulty kidney development. They contain a wide range of poorly differentiated cell states resembling various distorted developmental stages of the fetal kidney, and as a result, differ between patients in a continuous manner that is not well understood. Here, we used three computational approaches to characterize this continuous heterogeneity in high-risk blastemal-type Wilms' tumors. Using Pareto task inference, we show that the tumors form a triangle-shaped continuum in latent space that is bounded by three tumor archetypes with "stromal", "blastemal", and "epithelial" characteristics, which resemble the un-induced mesenchyme, the cap mesenchyme, and early epithelial structures of the fetal kidney. By fitting a generative probabilistic "grade of membership" model, we show that each tumor can be represented as a unique mixture of three hidden "topics" with blastemal, stromal, and epithelial characteristics. Likewise, cellular deconvolution allows us to represent each tumor in the continuum as a unique combination of fetal kidney-like cell states. These results highlight the relationship between Wilms' tumors and kidney development, and we anticipate that they will pave the way for more quantitative strategies for tumor stratification and classification.

Imaging Recommendations for Diagnosis, Staging, and Management of Renal Tumors

Renal cell carcinomas accounts for 2% of all the cancers globally. Most of the renal tumors are detected incidentally. Ultrasound remains the main screening modality to evaluate the renal masses. A multi -phase contrast enhanced computer tomography is must for characterizing the renal lesions. Imaging plays an important role in staging, treatment planning and follow up of renal cancers. In this review , we discuss the imaging guidelines for the management of renal tumors.

Enlarged Abdominal Lymph Node as a Cause of Polyhydramnios in the Course of Congenital Neonatal Leukaemia: A Case Report and Review of the Literature on Foetal Abdominal Tumours with Coexisting Polyhydramnios

Polyhydramnios represents a complication found in 0.2–2% of pregnancies, and it is usually diagnosed between 31 and 36 weeks of pregnancy. Although most cases of polyhydramnios are idiopathic, maternal diabetes or foetal malformations constitute frequent causes of the excessive accumulation of the amniotic fluid. Considering the latter, polyhydramnios may rarely be caused by foetal abdominal tumours, with the incidence rate of 2–14 cases per 100,000 live births. Congenital neonatal leukaemia (CNL) is a rare disease with a reported incidence rate of 5–8.6 cases per million live births. In the prenatal period, the ultrasound abnormalities associated with CNL include hepatomegaly and splenomegaly. In this paper, we presented a case of polyhydramnios caused by mechanical pressure on the foetal gastrointestinal tract by an enlarged lymph node in the course of CNL, as well as reviewing the available literature on foetal abdominal tumours with concurrent polyhydramnios.

Osteoporosis in Childhood Cancer Survivors: Physiopathology, Prevention, Therapy and Future Perspectives

Simple Summary

Anti-cancer treatments induced an increase in the childhood cancer survival rate. However, they are responsible for several long-term side effects in childhood cancer survivors, including osteoporosis. Cancer itself, a sedentary lifestyle, and an unhealthy diet might adversely affect bone health. Early identification and adequate management of bone fragility in childhood cancer survivors could be useful to prevent osteoporosis onset and consequently fragility fractures.

Abstract

The improvement of chemotherapy, radiotherapy, and surgical interventions, together with hematopoietic stem cell transplantation, increased childhood cancer survival rate in the last decades, reaching 80% in Europe. Nevertheless, anti-cancer treatments are mainly responsible for the onset of long-term side effects in childhood cancer survivors (CCS), including alterations of the endocrine system function and activity. In particular, the most frequent dysfunction in CCS is a metabolic bone disorder characterized by low bone mineral density (BMD) with increased skeletal fragility. BMD loss is also a consequence of a sedentary lifestyle, malnutrition, and cancer itself could affect BMD, thus inducing osteopenia and osteoporosis. In this paper, we provide an overview of possible causes of bone impairment in CCS in order to propose management strategies for early identification and treatment of skeletal fragility in this population.

A pediatric case of xanthogranulomatous pyelonephritis in the setting of Covid-19 and multi-system inflammatory syndrome (MIS-C)

Xanthogranulmatous pyelonephritis is a rare, chronic inflammatory pathology of the kidney. It most commonly arises in middle-aged females, but there are case reports and series described in the pediatric population. Here, we discuss the case of a 14 year old male who presented with xanthogranulomatous pyelonephritis in the setting of Covid-19 and multi-system inflammatory syndrome (MIS-C). As xanthogranulomatous pyelonephritis often mimics other diseases that are more prevalent in the pediatric population, our case was only definitively diagnosed with histopathology after surgical resection. This report is novel in that, to our knowledge, it is the first to describe xanthogranulomatous pyelonephritis in the setting of MIS-C.

LncRNA OSTM1-AS1 acts as an oncogenic factor in Wilms' tumor by regulating the miR-514a-3p/MELK axis

Wilms' tumor (WT) is the most typical basic renal tumor in children and is associated with a high recurrence rate and improper diagnosis. Long noncoding RNAs (lncRNAs) play important roles in WT development. However, the impact of the OSTM1 antisense RNA 1 (OSTM1-AS1) lncRNA on WT remains largely unexplored. Differential expression of OSTM1-AS1, miR-514a-3p and maternal embryonic leucine zipper kinase (MELK) in mice with WT cells was assessed via quantitative reverse transcription-PCR and western blotting. Changes in the proliferation, migration and apoptosis of WT cells after OSTM1-AS1, miR-514a-3p or MELK knockdown were assessed using the cell counting kit-8, Transwell and caspase-3 activity assays, respectively. Additionally, the tumorigenicity of WT cells after OSTM1-AS1 knockdown in vivo was analyzed using a xenograft tumor assay. The association among OSTM1-AS1, MELK and miR-514a-3p was confirmed using the RNA binding protein immunoprecipitation and luciferase reporter assays. OSTM1-AS1 and MELK were upregulated in WT cells, whereas miR-514a-3p was downregulated. OSTM1-AS1 was mostly observed in the cytoplasm, and its knockout suppressed WT cell migration and proliferation in vitro , triggered apoptosis and attenuated tumor development in vivo . MiR-514a-3p was sponged by OSTM1-AS1, and miR-514a-3p interference counteracted the tumoricidal effect of OSTM1-AS1 knockdown. MiR-514a-3p reduced WT progression by downregulating the expression of MELK, which is the target gene of miR-514a-3p. lncRNA OSTM1-AS1 acts as an oncogenic factor in WT by releasing MELK through sponging miR-514a-3p and could be a useful target for WT diagnosis and therapy.

Role of Ultrasonography in the Diagnosis of Wilms’ Tumour

Background. Wilms’ tumour or nephroblastoma is the most common renal malignancy encountered in the paediatric population. Imaging findings are of great importance to the surgeon, the oncologist and the radiologist in the diagnosis and the staging and surveillance of this tumour. Material and Methods. This study was carried out as a 10-year retrospective study of patients who were diagnosed with Wilms’ tumour. Results. The study included 12 boys and 11 girls. Ultrasound and computed tomography were performed in all cases. Ultrasonography was found to be superior to the CT examination when approximating the antero-posterior and transverse diameters; the computer-tomographic examination is cited as superior for estimating the invasion of nephroblastomas. Conclusions: Ultrasound has been shown to be effective in detecting the rupture of the renal capsule, tumour calcifications and invasion of the renal vein, pelvis and ureter. However, ultrasound cannot replace CT in the detection of lymphadenopathy and the invasion of adjacent organs.

Breast Cancer Secondary to Radiation Therapy in a Patient With Wilms Tumor

Wilms tumor, one of the most common childhood malignancies, is typically treated with a combination of chemotherapy, radiation, and surgical resection. Wilms tumor survivors who received radiation therapy are, however, at a higher risk of secondary malignancies and need vigilant monitoring. We present the case of a 35-year-old female with history of Wilms tumor at age five, who received radiation therapy for pulmonary metastasis, and was found to have breast cancer at the age of 35. We discuss different protocols in treatment of Wilms tumor and current secondary malignancy screening recommendations. We also recognize the importance of screening guideline awareness among primary care physicians and its mortality and morbidity implications.

MF, Dueñas-Ramírez JC, Idrobo AA. Abordaje mínimamente invasivo del tumor de Wilms unilateral: un reporte de caso y revisión de la literatura

Introducción. El tumor de Wilms es la neoplasia abdominal más común en pacientes pediátricos. En la mayoría de los casos se presenta como una masa unilateral indolora en el abdomen. El objetivo de este artículo fue presentar el caso de una paciente de 4 años con tumor de Wilms unilateral derecho manejado con cirugía mínimamente invasiva en el Hospital Universitario del Valle. Métodos. Revisión de la historia clínica e imágenes de la paciente, descripción de la técnica quirúrgica y revisión de la literatura del manejo de tumor de Wilms unilateral. Caso clínico. Paciente femenina de 4 años quien consultó en abril de 2019 por un cuadro clínico de dolor abdominal y sensación de masa en flanco derecho. Se realizó ecografía abdominal donde se encontró imagen nodular heterogénea de contornos definidos en riñón derecho, con riñón izquierdo normal. Se hizo diagnóstico de tumor de Wilms unilateral y se llevó a cirugía mediante abordaje mínimamente invasivo, con buena evolución postoperatoria. Conclusión. La cirugía es el pilar del manejo, y la nefrectomía mediante abordaje laparoscópico para casos seleccionados, en manos entrenadas, tiene la suficiente eficacia, seguridad y cumplimiento de los principios quirúrgicos y oncológicos que provee la cirugía abierta.

Genitourinary Tract Tumors in Children: An Update

BACKGROUND

Genitourinary tract tumors in children are less common than in adults. Most of these tumors have different genetic backgrounds, clinical presentation, and oncologic behavior than their adult counterpart. As a result of low prevalence in children, some of the treatment approaches and recommendations are based on treatment experience in adult patients. However, thanks to scientific and technological development, survival rates have risen considerably.

OBJECTIVE

This paper presents a review of the principal features of the tumors involving the genitourinary tract in children and an update in genetic background, diagnosis, and treatment.

METHODS

A narrative review was performed on published literature about genitourinary tract tumors in pediatric patients. Papers presented in English and Spanish literature were reviewed. PubMed, Science Direct, and SciELO databases were used to collect information and present this article.

RESULTS

Kidney tumors are the most common type of genitourinary tumors in children. Among those, Wilms tumor represents the majority of cases and shows the successful work of clinical trial groups studying this tumor type. Other tumors involving the genitourinary tract in children include Rhabdomyosarcoma, Transitional cell carcinoma, Testicular, and Adrenal tumors.

CONCLUSION

Genitourinary tract tumors in children represent significant morbidity and economic burden, so awareness in early diagnosis represents improvement in treatment, clinical, and oncological outcomes.

Pediatric Pulmonary Nodules: Imaging Guidelines and Recommendations

Incidental pulmonary nodules are not infrequently identified on computed tomography imaging in the pediatric population and can be a challenge in suggesting appropriate follow-up recommendations. An evidence-based and practical imaging approach for diagnosis and appropriate directed management is essential for optimal patient care. This article provides an up-to-date review of the pediatric pulmonary nodule literature and suggests a practical algorithm to manage pulmonary nodules in the pediatric population.

Pediatric Abdominal Masses: Imaging Guidelines and Recommendations

Pediatric abdominal masses are commonly encountered in the pediatric population, with a broad differential diagnosis that encompasses benign and malignant entities. The primary role of abdominal imaging in the setting of a suspected pediatric abdominal mass is to establish its presence, as nonneoplastic entities can mimic an abdominal mass, and to identify characteristic imaging features that narrow the differential diagnosis. In the setting of a neoplasm, various imaging modalities play an important role to characterize the mass, stage extent of disease, and assist in presurgical planning. The purpose of this article is to discuss a practical imaging algorithm for suspected pediatric abdominal masses and to describe typical radiological findings of the commonly encountered abdominal masses in neonates and children with emphasis on imaging guidelines and recommendations.

PET/MRI in paediatric disease

Nuclear medicine and molecular imaging have a small but growing role in the management of paediatric and neonatal diseases. During the past decade, combined PET/MRI has emerged as a clinically important hybrid imaging modality in paediatric medicine due to diagnostic advantages and reduced radiation exposure compared to alternative techniques. The applications for nuclear medicine, radiopharmaceuticals and combined PET/MRI in paediatric diagnosis is broadly similar to adults, however there are some key differences. There are a variety of clinical applications for PET/MRI imaging in children including, but not limited to, oncology, neurology, cardiovascular, infection and chronic inflammatory diseases, and in renal-urological disorders. In this article, we review the applications of PET/MRI in paediatric and neonatal imaging, its current role, advantages and disadvantages over other hybrid imaging techniques such as PET/CT, and its future applications. Overall, PET/MRI is a powerful imaging technology in diagnostic medicine and paediatric diseases. Higher soft tissue contrasts and lower radiation dose of the MRI makes it the superior technology compared to other conventional techniques such as PET/CT or scintigraphy. However, this relatively new hybrid imaging has also some limitations. MRI based attenuation correction remains a challenge and although methodologies have improved significantly in the last decades, most remain under development.

Imaging for Staging of Pediatric Abdominal Tumors: An Update, From the AJR Special Series on Cancer Staging

The three most common pediatric solid tumors of the abdomen are neuroblastoma, Wilms tumor, and hepatoblastoma. These embryonal tumors most commonly present in the first decade of life. Each tumor has unique imaging findings, including locoregional presentation and patterns of distant spread. Neuroblastoma, Wilms tumor, and hepatoblastoma have unique staging systems that rely heavily on imaging and influence surgical and oncologic management. The staging systems include image-defined risk factors for neuroblastoma, the Children's Oncology Group staging system for Wilms tumor, and the pretreatment extent of tumor system (PRETEXT) for hepatoblastoma. It is important for radiologists to be aware of these staging systems to optimize image acquisition and interpretation. This article provides a practical and clinically oriented approach to the role of imaging in the staging of these common embryonal tumors of childhood. The selection among imaging modalities, key findings for determining tumor stage, and the role of imaging in posttreatment response evaluation and surveil-lance are discussed. Recent updates to the relevant staging systems are highlighted with attention to imaging findings of particular prognostic importance. The information presented will help radiologists tailor the imaging approach to the individual patient and guide optimal oncologic management.

Wilms' Tumor in Horseshoe Kidney

Wilms' tumor is the most common malignant kidney tumor found in children. The Horseshoe kidney is the most common renal fusion malformation. However, Wilms' tumor is rarely identified in horseshoe kidney patients. Multimodal treatments in Wilms' tumor can play important roles in increasing the survival rate. In this study, we report the case of a 6-year-old boy in whom a Wilms' tumor was identified in a horseshoe kidney. The tumor was successfully treated with preoperative chemotherapy, followed by surgical resection.

Relapsed Wilms' Tumor Presenting as Metastasis to the Zygoma

Wilms’ tumor accounts for the majority of renal tumors in children. Rarely, Wilms’ tumor may metastasize to the bone. We present a case of a 15-month-old female who presented with severe abdominal distension and signs of cachexia. Abdominal ultrasonography and radiography of the abdomen both demonstrated a large abdominal mass. Follow-up computed tomography of the abdomen revealed a heterogeneous intra-abdominal mass arising from the left kidney which was surrounded by a thin rim of renal parenchyma. Biopsy of the mass revealed findings consistent with Wilms’ tumor. The patient was 14 months status-post nephrectomy and chemoradiation but returned to the clinic with left facial swelling. Magnetic resonance imaging of the face demonstrated a multilobulated, heterogeneously enhancing solitary mass lesion in the left temple centered in the left zygoma with signs of bone breakdown. Despite its rarity, metastatic Wilms’ tumor to bone should be considered in a child presenting with a new focal mass overlying bony-structures.

Atypical pulmonary metastases in children: pictorial review of imaging patterns

Pulmonary metastases typically present as well-circumscribed solid nodules, often with a basilar and peripheral distribution due to hematogenous spread. When an atypical pattern of metastasis occurs, a lack of recognition may result in understaging or a delay in diagnosis. The purpose of this article is to review the imaging findings of atypical pulmonary metastatic disease in children. Atypical pulmonary metastatic patterns that can be seen in children include cavitary lesions, calcified pulmonary nodules, nodules with peritumoral halos, tree-in-bud or strial pattern secondary to tumor in peripheral pulmonary arterial branches, lymphangitic carcinomatosis, and miliary disease. An awareness of the spectrum of imaging findings of atypical pulmonary metastases along with an understanding of histopathological underpinnings will allow the radiologist to make an accurate diagnosis.

Imaging of childhood urologic cancers: current approaches and new advances

Urologic tumors make up approximately 10% of all pediatric cancers, and include a variety of different histologies and imaging considerations. In this review, we discuss standard radiologic approaches for children with tumors arising in the genitourinary system, and identify important ways in which imaging affects the differential diagnosis, preoperative planning, and staging of these tumors. In addition, we provide an update on strategies to reduce the time of imaging, which may obviate the need for sedation in younger patients. Efforts to reduce a patient’s overall radiation exposure and subsequent risk of second malignancy are also detailed, including recent work on surveillance imaging following completion of therapy. Finally, we highlight new techniques such as radiomics that are now being investigated for patients with these malignancies.

The Potential Roles of RNA N6-Methyladenosine in Urological Tumors

N6-methyladenosine (m⁶A) is regarded as the most abundant, prevalent and conserved internal mRNA modification in mammalian cells. M⁶A can be catalyzed by m⁶A methyltransferases METTL3, METTL14 and WTAP (writers), reverted by demethylases ALKBH5 and FTO (erasers), and recognized by m⁶A -binding proteins such as YTHDF1/2/3, IGF2BP1/2/3 and HNRNPA2B1 (readers). Emerging evidence suggests that m⁶A modification is significant for regulating many biological and cellular processes and participates in the pathological development of various diseases, including tumors. This article reviews recent studies on the biological function of m⁶A modification and the methylation modification of m⁶A in urological tumors.

ALKBH5 gene polymorphisms and Wilms tumor risk in Chinese children: A five-center case-control study

BACKGROUND

Wilms tumor is a frequently diagnosed renal cancer among children with unclear genetic causes. N6-methyladenosine (m⁶ A) modification genes play critical roles in tumorigenesis. However, whether genetic variations of m⁶ A modification genes predispose to Wilms tumor remain unclear. ALKBH5 (AlkB homolog 5), a crucial member of m⁶ A modification genes, encodes a demethylase that functions to reverse m⁶ A RNA methylation.

METHODS

Herein, we evaluated the association of single nucleotide polymorphisms (SNPs) in the m⁶ A modification gene ALKBH5 and Wilms tumor susceptibility in a large multi-center case-control study. A total of 414 Wilms tumor cases and 1199 healthy controls were genotyped for ALKBH5 rs1378602 and rs8400 polymorphisms by TaqMan.

RESULTS

No significant association was detected between these two polymorphisms and Wilms tumor risk. Moreover, 1, 2, and 1-2 protective genotypes (rs1378602 AG/AA or rs8400 GG) did not significantly reduce Wilms tumor risk, compared with risk genotypes only. Stratification analysis revealed a significant relationship between rs1378602 AG/AA genotypes and decreased Wilms tumor risk in children in clinical stage I diseases [adjusted odds ratio (OR) = 0.56, 95% confidence interval (CI) = 0.32-0.98, P = .042]. The presence of 1-2 protective genotypes was correlated with decreased Wilms tumor risk in subgroups of age > 18 months, when compared to the absence of protective genotypes (adjusted OR = 0.74, 95% CI = 0.56-0.98, P = .035).

CONCLUSION

Collectively, our results demonstrate that ALKBH5 SNPs may exert a weak influence on susceptibility to Wilms tumor. This finding increases the understanding of the role of the m⁶ A gene in tumorigenesis of Wilms tumor.