Preoperative three-dimensional modelling and virtual reality planning aids nephron sparing surgery in a child with bilateral Wilms tumour

Bilateral Wilms tumour (BWT) is a surgically challenging condition. Virtual reality (VR) reconstruction aids surgeons to foresee the anatomy ahead of Nephron Sparing Surgery (NSS). Three-dimensional (3D) visualisation improves the anatomical orientation of surgeons performing NSS. We herewith report a case of BWT where VR planning and 3D printing were used to aid NSS. Conventional imaging is often found to be inadequate while assessing the tumour-organ-vascular anatomy. Advances like VR and 3D printing help surgeons plan better for complex surgeries like bilateral NSS. Next-generation extended reality tools will likely aid robotic-assisted precision NSS and improve patient outcomes.

Congenital Mesoblastic Nephroma Mimic Wilms Tumor on 18 F-FDG PET/CT and PET/MR

ABSTRACT

Congenital mesoblastic nephroma is an extremely rare, low-grade malignant renal tumor in children. A 10-month-old boy and a 4-month-old girl were admitted to our hospital with a huge abdominal mass. For staging of the mass, 18 F-FDG PET/CT and PET/MR were performed showing a huge heterogeneous abdominal mass accompanied by extensive heterogeneous aggregation. Both of them were highly suspected to be Wilms tumor, the most common renal malignant tumor in children. However, histopathological examination after surgery confirmed congenital mesodermal nephroma.

Clinical value of ultrasound in adult Wilms' tumor patient with uremia: A case report and literature review

RATIONALE

Wilms' tumor (WT) is the most common pediatric kidney malignancy and is rarely found in adults. Nonspecific clinical symptoms and imaging features often lead to delayed diagnosis or misdiagnosis of adult WT, resulting in poor clinical outcomes. Ultrasound (US), as an efficient and noninvasive examination method, has been widely used in clinical diagnosis and treatment. Therefore, various US evidence is meaningful to improve understanding of adult WT characteristics in ultrasound.

PATIENT CONCERNS

A 45-year-old female patient with uremia (regular hemodialysis for 13 years) with painless gross hematuria was diagnosed with a right kidney tumor penetrating to the lung. Preoperatively, B-mode ultrasonography showed an ill-defined hyperechoic mass in the right kidney, which revealed an unclear border, uneven internal echoes, and calcification. Besides, the internal blood flow signal of the tumor was detected. Contrast-enhanced ultrasound (CEUS) showed an uneven hyper-enhancement in the tumor ("fast in and slow out"). Contrast-enhanced computed tomography of the kidney indicated a similar result as the CEUS. Moreover, the chest CT identified multiple pulmonary metastatic nodules.

DIAGNOSES

An ultrasound-guided percutaneous core needle biopsy of the tumor proceeded to make a definite diagnosis of adult WT (epithelial type).

INTERVENTIONS

The patient was treated with tislelizumab.

OUTCOMES

No progress was found to date.

LESSONS

We report the first case in which CEUS was performed in an adult WT patient with uremia and multiple pulmonary metastases. The features obtained by the US can help in the diagnosis of adult WT and direct further diagnostic procedures.

CT-based identification of pediatric non-Wilms tumors using convolutional neural networks at a single center

BACKGROUND

Deep learning (DL) is more and more widely used in children's medical treatment. In this study, we have developed a computed tomography (CT)-based DL model for identifying undiagnosed non-Wilms tumors (nWTs) from pediatric renal tumors.

METHODS

This study collected and analyzed the preoperative clinical data and CT images of pediatric renal tumor patients diagnosed by our center from 2008 to 2020, and established a DL model to identify nWTs noninvasively.

RESULTS

A total of 364 children who had been confirmed by histopathology with renal tumors from our center were enrolled, including 269 Wilms tumors (WTs) and 95 nWTs. For DL model development, all cases were randomly allocated to training set (218 cases), validation set (73 cases), and test set (73 cases). In the test set, the DL model achieved area under the curve of 0.831 (95% CI: 0.712-0.951) in discriminating WTs from nWTs, with the accuracy, sensitivity, and specificity of 0.781, 0.563, and 0.842, respectively. The sensitivity of our model was higher than a radiologist with 15 years of experience.

CONCLUSIONS

We presented a DL model for identifying undiagnosed nWTs from pediatric renal tumors, with the potential to improve the image-based diagnosis.

IMPACT

Deep learning model was used for the first time to identify pediatric renal tumors in this study. Deep learning model can identify non-Wilms tumors from pediatric renal tumors. Deep learning model based on computed tomography images can improve tumor diagnosis rate.

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.

Botryoid Wilms Tumor with Left-Sided Inferior Vena Cava: A Case Report

Wilms tumor (WT) is the second most common solid tumor in pediatric population. Botryoid WT is an uncommon growth pattern of WT, which is characterized by tumor extension into collecting system. A case of a 27-month-old boy with botryoid WT and left-sided inferior vena cava is reported in this article to emphasize the importance of preoperative imaging in preoperative planning.

The clinical impact of observer variability in lung nodule classification in children with Wilms tumour

OBJECTIVES

To investigate the extent to which observer variability of computed tomography (CT) lung nodule assessment may affect clinical treatment stratification in Wilms tumour (WT) patients, according to the recent Société Internationale d'Oncologie Pédiatrique Renal Tumour Study Group (SIOP-RTSG) UMBRELLA protocol.

METHODS

I: CT thoraces of children with WT submitted for central review were used to estimate size distribution of lung metastases. II: Scans were selected for blinded review by five radiologists to determine intra- and inter-observer variability. They assessed identical scans on two occasions 6 months apart. III: Monte Carlo simulation (MCMC) was used to predict the clinical impact of observer variation when applying the UMBRELLA protocol size criteria.

RESULTS

Lung nodules were found in 84 out of 360 (23%) children with WT. For 21 identified lung nodules, inter-observer limits of agreement (LOA) for the five readers were ±2.4 and ±1.4 mm (AP diameter), ±1.9 and ±1.8 mm (TS diameter) and ±2.0 and ±2.4 mm (LS diameter) at assessments 1 and 2. Intra-observer LOA across the three dimensions were ±1.5, ±2.2, ±3.5, ±3.1 and ±2.6 mm (readers 1-5). MCMC demonstrated that 17% of the patients with a 'true' nodule size of ≥3 mm will be scored as <3 mm, and 21% of the patients with a 'true' nodule size of <3 mm will be scored as being ≥3 mm.

CONCLUSION

A significant intra-inter observer variation was found when measuring lung nodules on CT for patients with WT. This may have significant implications on treatment stratification, and thereby outcome, when applying a threshold of ≥3 mm for a lung nodule to dictate metastatic status.

Multi-modality imaging and therapeutics used in a case of canine spinal nephroblastoma

A 4-year-old castrated male golden retriever dog was brought to a veterinary teaching hospital for evaluation of acute progressive paraparesis. Neurological examination indicated a spinal cord lesion between the third thoracic vertebra and third lumbar vertebrae. Magnetic resonance imaging (MRI) revealed an intradural, extra medullary, and/or intramedullary mass centered over the eleventh and twelfth thoracic disc space. The dog underwent cytoreductive surgery and histopathologic analysis diagnosed a nephroblastoma. Following this, the dog underwent multimodal therapy, including multiple surgeries, 2 courses of radiation, and combination chemotherapy. The dog had serial restaging using MRI, computed tomography (CT), and fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography throughout the course of therapy. The dog survived 350 d from date of first presentation until humane euthanasia was elected due to worsening of neurologic status. During postmortem examination, extensive infiltration of the spinal cord by nephroblastoma cells was discovered as well as pulmonary metastatic disease. Key clinical message: Based on the literature search, this is the first case in which surgery, radiation therapy, and chemotherapy were all used for the treatment of canine spinal nephroblastoma. This case report details the aggressive nature of a case of canine spinal nephroblastoma despite multi-modal therapy.

Diagnosis, Management, and Challenges in Synchronous Bilateral Wilms Tumor in a Horseshoe Kidney: A Case Report

Horseshoe kidney (HK) refers to a congenital malformation that results from fusion of both the kidneys at one pole, and is the most common renal fusion defect with an incidence of 1 in 400 to 600 individuals. Synchronous bilateral development of Wilms tumor (WT) in an HK is extremely rare. Here, we present a case of synchronous bilateral WT in an HK in an 18-month-old girl. The patient received 12 weeks of preoperative chemotherapy followed by 2-step surgical resection including nephron-sparing surgery (NSS) in both kidneys and left nephrectomy because of positive surgical margin and adjuvant chemotherapy. The patient is still in remission and asymptomatic 6 months after the completion of treatment. In this report, we discuss the treatment modalities of synchronous bilaterally located WT in HK. We conclude that successful outcomes can be obtained with preoperative chemotherapy and NSS in such cases even in the presence of advanced disease and complex anatomic conditions. In addition, the deepest tumor point can be reached during NSS, but total nephrectomy should be considered regarding the possibility of microscopic residue.

Ganglioneuroma Mimicking Nephroblastoma: A Case Report

Ganglioneuroma is an uncommon benign, slow-growing tumor arising from the neural crest. It rarely turns malignant even after decades of benign existence. Imaging modalities give a definite clue to the existence of a neurogenic mass but it is finally diagnosed on histopathology examination. Here, a 3-year-old girl presented with ganglioneuroma that mimicked renal mass on imaging in a tertiary care hospital, Dhaka, Bangladesh on January, 2016. Later on, it was confirmed as neuroganglioma by histopathological examination. As treatment differs widely between ganglioneuroma and nephroblastoma, a minor mistake in the accurate diagnosis may endanger the life of a patient through potential adverse effects of therapy. So, we should keep in mind about ganglioneuroma regarding evaluation of any kidney or abdominal masses.

Neonatal Renal Tumors

Renal tumors are rare in the neonatal period. Although some may be detected prenatally, a greater proportion present after birth, most often with a palpable abdominal mass with or without other associated symptoms. Cross-sectional imaging is typically followed by radical nephrectomy to make a specific histologic diagnosis to determine the need for additional therapy. This article reviews the clinical presentation, workup, treatment, and outcomes for neonates with some of the more common renal tumors seen in this population.

Imaging of Wilms tumor: an update

Wilms tumor is the most common pediatric renal tumor, accounting for approximately 7% of all childhood cancers. Imaging plays an important role in the detection, staging, post-therapy evaluation and surveillance of Wilms tumor. Wilms tumor can be detected during surveillance of a known cancer predisposition or after a child presents with symptoms. In this manuscript we describe an evidence-based approach to the initial evaluation of Wilms tumor using current guidelines from the Children's Oncology Group (COG). We illustrate the COG staging system for pediatric renal tumors and highlight key imaging findings that are critical for surgical management. We also discuss the controversies regarding detection and significance of <5-mm pulmonary nodules at initial staging. And finally, we present some thoughts regarding surveillance of Wilms tumor, where overall survival has now approached 90%.

Texture Analysis to Differentiate Malignant Renal Tumors in Children Using Gray-Scale Ultrasonography Images

We assessed the feasibility of texture analysis to differentiate Wilms tumor, clear cell sarcoma and rhabdoid tumor of the kidney in children using gray-scale ultrasonography images. Children who had pre-operative renal ultrasonography images of the three tumors from January 2002 to February 2017 were retrospectively included as the test set, and children with the same criteria from March 2017 to December 2018 were included as the validation set. From histogram and second-order statistics, features were compared between the tumors, and diagnostic performances were assessed. Among a total of 32 children (24 children with Wilms tumors, five children with clear cell sarcomas and three children with rhabdoid tumors) from the test set, features from the second-order statistics showed an area under the curve greater than 0.89 for differentiating Wilms tumor from the others. These features aided in the differentiation of tumor type in the two children with Wilms tumors in the validation set. Therefore, texture analysis from gray-scale ultrasonography images can be used to differentiate Wilms tumors from clear cell sarcomas and rhabdoid tumors in children.

Comparison of 3-Dimensional and Augmented Reality Kidney Models With Conventional Imaging Data in the Preoperative Assessment of Children With Wilms Tumors

IMPORTANCE

Nephron-sparing surgery can be considered in well-defined cases of unilateral and bilateral Wilms tumors, but the surgical procedure can be very challenging for the pediatric surgeon to perform.

OBJECTIVE

To assess the added value of personalized 3-dimensional (3-D) kidney models derived from conventional imaging data to enhance preoperative surgical planning.

DESIGN, SETTING, AND PARTICIPANTS

In a survey study, the conventional imaging data of 10 Dutch children with Wilms tumors were converted to 3-D prints and augmented reality (AR) holograms and a panel of pediatric oncology surgeons (n = 7) assessed the quality of the different imaging methods during preoperative evaluation. Kidney models were created with 3-D printing and AR using a mixed reality headset for visualization.

MAIN OUTCOMES AND MEASURES

Differences in the assessment of 4 anatomical structures (tumor, arteries, veins, and urinary collecting structures) using questionnaires. A Likert scale measured differences between the imaging methods, with scores ranging from 1 (completely disagree) to 5 (completely agree).

RESULTS

Of the 10 patients, 7 were girls, and the mean (SD) age was 3.7 (1.7) years. Compared with conventional imaging, the 3-D print and the AR hologram models were evaluated by the surgeons to be superior for all anatomical structures: tumor (median scores for conventional imaging, 4.07; interquartile range [IQR], 3.62-4.15 vs 3-D print, 4.67; IQR, 4.14-4.71; P = .008 and AR hologram, 4.71; IQR, 4.26-4.75; P = .002); arteries (conventional imaging, 3.62; IQR, 3.43-3.93 vs 3-D print, 4.54; IQR, 4.32-4.71; P = .002 and AR hologram, 4.83; IQR, 4.64-4.86; P < .001), veins (conventional imaging, 3.46; IQR 3.39-3.62 vs 3-D print, 4.50; IQR, 4.39-4.68; P < .001 and AR hologram, 4.83; IQR, 4.71-4.86; P < .001), and urinary collecting structures (conventional imaging, 2.76; IQR, 2.42-3.00 vs 3-D print, 3.86; IQR, 3.64-4.39; P < .001 and AR hologram, 4.00; IQR, 3.93-4.58; P < .001). There were no differences in anatomical assessment between the two 3-D techniques (the 3-D print and AR hologram).

CONCLUSIONS AND RELEVANCE

In this study, the 3-D kidney models were associated with improved anatomical understanding among the surgeons and can be helpful in future preoperative planning of nephron-sparing surgery for Wilms tumors. These models may be considered as a supplementary visualization in clinical care.

A case report of infantile cystic nephroblastoma

BACKGROUND

Nephroblastoma (NB) is a malignant embryonal neoplasm derived from nephrogenic blastemal cells. NB usually forms a solid mass, but in extremely rare cases, it may show cystic changes.

CASE PRESENTATION

A six-month-old girl with persistent high fevers was found to have pyuria and bacteriuria. Ultrasonography revealed multilocular cysts in the right kidney. Right nephrectomy was performed with cyst wall rupture during surgery. An intraoperative rapid diagnosis, based on peritoneal fluid cytology, confirmed three components of blastemal, stromal, and epithelial cells. The blastemal cells were dyshesive, with scant to no cytoplasm and were the predominant cell type. The spindle-shaped stromal cells were arranged in fascicles. The epithelial cells demonstrated tubular structures. Macroscopically, the resected cystic tumor measured 80 mm in maximum diameter with a prominently thin cyst wall, but solid areas were also apparent. Histologically, the tumor was diagnosed as cystic NB (blastemal-predominant) displaying a triphasic pattern. Hyperchromatic nuclei and apoptotic bodies were found. The clinical stage classification of Japan Wilms Tumor Study group was 3. The patient was treated with chemotherapy and radiotherapy. Tumor recurrence and metastasis have not been observed in the 8 months since surgery.

CONCLUSION

This is an extremely rare case of infantile cystic NB. We diagnosed the NB cells that appeared in the peritoneal fluid by intraoperative rapid cytology. Cytological examination proved to be a very useful technique for determining the clinical stage of NB. Additionally, we propose that massive tumor degeneration and necrosis be considered as a pathogenic mechanism of cyst formation in NB.

[Nephroblastoma in a 2-year-old female dog]

An intact female 2-year-old boxer presented with polydipsia, polyuria, and decreased feed intake. Palpation of the abdomen was painful. Sonography revealed an abdominal mass of the left kidney causing displacement of the organs located in the cranial and mid-abdomen. Dimen sion and invasiveness of the process were evaluated both by contrast enhanced ultrasound (CEUS) and contrast-enhanced computed tomography. Histopathological examination of a biopsy sample revealed a nephroblastoma. The case report describes the clinical, sonographic, and computed tomographic results and the outcome in the untreated dog over a period of 5 months.

Technical Considerations for Nephron-Sparing Surgery in Children: What Is Needed to Preserve Renal Units?

BACKGROUND

Chemotherapy is used preoperatively for children with bilateral Wilms tumor (BWT) or unilateral high-risk Wilms tumor (UHRWT) to promote tumor regression to facilitate renal preservation with nephron-sparing surgery (NSS). In adults, various surgical techniques have been described to preserve renal tissue. Few studies have examined the use of surgical adjuncts in NSS in children with renal tumors.

METHODS

We performed a multi-institutional retrospective review of patients with BWT or UHRWT. Patient demographics, tumor size at diagnosis, following neoadjuvant chemotherapy, utilization of surgical adjuncts including intraoperative ultrasound (IOUS), margin status, complications, renal function, and follow-up were recorded.

RESULTS

The cohort comprised 23 patients: 18 BWT, 3 UHRWT, and 2 patients with solitary kidney. Twenty-two of the 23 patients had successful NSS. IOUS was used 19 times, and seven had positive margins after surgery. Cooling/vascular isolation was used six times. At a median follow-up of 18 mo, median estimated glomerular filtration rate Schwartz was 126 mL/min/1.73 m² and median serum creatinine 0.39 mg/dL in the 22 patients who had successful NSS. There have been no tumor recurrences.

CONCLUSIONS

In patients with BWT and UHRWT, surgical adjuncts such as cooling/vascular isolation are uncommonly performed. IOUS may be helpful but does not guarantee negative microscopic margins.

LEVEL OF EVIDENCE

Level 4, Case series with no comparison group.

Cardiac-Sparing Whole Lung Intensity Modulated Radiation Therapy in Children With Wilms Tumor: Final Report on Technique and Abdominal Field Matching to Maximize Normal Tissue Protection

PURPOSE

Cardiac-sparing whole lung intensity modulated radiation therapy (WL IMRT) has been shown to improve cardiac protection and lung volume dose coverage compared with standard anteroposterior techniques. This dosimetry study had 2 aims: To determine the dosimetric advantages of a modified WL IMRT (M-WL IMRT) technique, designed to reduce radiation exposure to the thyroid gland and breast tissues, compared with standard WL IMRT (S-WL IMRT) and to determine the dosimetric advantages of M-WL IMRT and dosimetrically matched abdomen and flank radiation therapy (RT) fields designed to reduce normal tissue exposure compared with standard field matching techniques.

METHODS AND MATERIALS

Computed tomography scans of the chest and abdomen that were obtained during computed tomography simulation of 10 female children were used. For Aim 1, for S-WL IMRT, the planning target volume (PTV) was obtained with a 1-cm expansion of the 4-dimensional lung volume (internal target volume). For M-WL IMRT, the PTV was reduced around the breast and thyroid gland to facilitate thyroid and breast sparing. For Aim 2, standard matching techniques for 3-dimensional anterior/posterior-posterior/anteriorwhole lung and abdominal RT fields were compared with a new dosimetric matching technique for WL IMRT and abdomen and flank fields. For both aims, the dose coverage of the lungs and radiation exposure to normal tissues (heart, thyroid, breasts) were statistically compared.

RESULTS

Compared with S-WL IMRT, the M-WL IMRT technique provided similar lung PTV dose coverage and a significantly superior reduction in mean breast and thyroid doses, without compromising cardiac protection. The M-WL IMRT technique combined with a dosimetrically matched abdomen and flank fields showed significantly superior normal tissue protection compared with standard matched anterior/posterior-posterior/anteriorlung and abdomen and flank RT fields.

CONCLUSIONS

This study has shown that the M-WL IMRT technique can reduce radiation exposure to the thyroid gland and breast tissue without compromising cardiac protection and 4-dimensional lung volume dose coverage. This report also describes a new dosimetric matching technique between WL IMRT and abdomen and flank fields that will improve normal tissue sparing compared with standard techniques.

Staging and following common pediatric malignancies: MRI versus CT versus functional imaging

Most pediatric malignancies require some form of cross-sectional imaging, either for staging or response assessment. The majority of these are solid tumors and this review addresses the role of MRI, as well as other cross-sectional and functional imaging techniques, for evaluating the most common pediatric solid tumors. The primary emphasis is on neuroblastoma, hepatoblastoma and Wilms tumor, three of the most common non-central-nervous-system (CNS) pediatric solid tumors encountered in young children. The initial focus will be a review of the imaging techniques and approaches used for diagnosis, staging and early post-treatment response assessment, followed by a discussion of the role surveillance imaging plays in pediatric oncology and a brief review of other emerging imaging techniques. The lessons learned here can be applied to most other pediatric tumors, including rhabdomyosarcoma, Ewing sarcoma and osteosarcoma, as well as germ cell tumors, neurofibromatosis and other rare tumors. Although lymphoma, in particular Hodgkin lymphoma, represents one of the more common pediatric malignancies, this is not discussed in detail here. Rather, many of the lessons that we have learned from lymphoma, specifically with regard to how we integrate both anatomical imaging and functional imaging techniques, is applied to the discussion of the other pediatric solid tumors.

Lymphography in Childhood Cancer

Lymphographic investigations were done in 139 children (84 males and 55 females). Up to the age of 10 years the examination was performed in anesthesia; after that age suitable sedation only was given. The radiographic pattern of the lymph node involvement in this type of tumor is the same in children as in adults. Peculiar patterns were observed in neuroblastoma and in Ewing's sarcoma. 78 patients (57.4%) were suffering from systemic disease and 59 (41.9%) from solid tumors; in 2 cases the clinical diagnosis of tumor was not borne out by the histologic findings. In 35.3% of the cases with Hodgkin's disease and in 29% of supradiaphragmatic reticuloendothelial sarcoma lymphography revealed subdiaphragmatic lymph node involvement. In the stage III and IV patients lymphography was always pathologic. Pathologic lymph nodes were found in 3/10 patients with lymphoma arising in Waldeyer's tonsillar ring. Metastases were present in 40/59 of the cases of solid tumor (68.9%); the incidence of metastases was especially high in neuroblastoma (20/24), in rhabdomyosarcoma (4/5) and in tumors of the gonades (7/9). 16 cases were operated on; 2 false positives were found for lymph nodes in which there was pronounced reactive inflammatory hyperplasia.

Extrarenal teratoma with nephroblastoma in the retroperitoneum: Case report and literature review

RATIONALE

Teratoma with nephroblastoma is a rare disease. The most common site at which teratoma with nephroblastoma occurs is the kidney. The mechanisms underlying the development of teratoma with nephroblastoma have not been fully elucidated.

PATIENT CONCERNS

In the current report, we describe the clinical characteristics of a 3-year-old girl with a complaint of a painless abdominal mass in the upper right side of the body. Ultrasonography and computed tomography revealed a cystic-solid mass with a clear boundary.

DIAGNOSIS

Surgical resection and a subsequent pathological examination confirmed that the mass contained teratoma tissues and renal blastemal components, which supports the diagnosis of teratoma with nephroblastoma.

INTERVENTIONS

The patient underwent an exploratory laparotomy through a transverse abdominal incision. Complete resection of the mass was performed in this patient.

OUTCOMES

The patient's postoperative course was uneventful and she was discharged on the 8th postoperative day. The girl had no complaints during the 2 years follow-up period.

LESSONS

Teratoma with nephroblastoma is a rare entity that typically presents in childhood. Due to its rarity, no standardized criteria have been established for the categorization and treatment of these lesions. However, a complete excision of this tumor allows the diagnosis to be confirmed and lowers the risk of recurrence.

Paraneoplastic Cushing Syndrome Due To Wilm's Tumor

Paraneoplastic syndromes are rare disorders that are triggered by an altered immune system response to neoplasm. Paraneoplastic syndromes may be the first or the most prominent manifestations of cancer. Wilm's tumor is the most frequent pediatric renal malignancy and usually presents with abdominal mass. Unusual presentations like acquired von Willebrand disease, sudden death due to pulmonary embolism and Cushing syndrome have been described in the literature. Cushing syndrome, as the presenting symptom of a malignant renal tumor in children, is a very rare entity. Few case reports are available in the literature exploring the option of preoperative chemotherapy as well as upfront nephrectomy. We report a rare case of paraneoplastic Cushing syndrome due to a Wilm's tumor. Based on gradual decrease of postoperative weight, blood pressure, serum adrenocorticotropic hormone, and plasma cortisol levels, along with histological confirmation of Wilm's tumor, paraneoplastic Cushing syndrome due to Wilm's tumor was confirmed.

Intra-Tumor Genetic Heterogeneity in Wilms Tumor: Clonal Evolution and Clinical Implications

The evolution of pediatric solid tumors is poorly understood. There is conflicting evidence of intra-tumor genetic homogeneity vs. heterogeneity (ITGH) in a small number of studies in pediatric solid tumors. A number of copy number aberrations (CNA) are proposed as prognostic biomarkers to stratify patients, for example 1q+ in Wilms tumor (WT); current clinical trials use only one sample per tumor to profile this genetic biomarker. We multisampled 20 WT cases and assessed genome-wide allele-specific CNA and loss of heterozygosity, and inferred tumor evolution, using Illumina CytoSNP12v2.1 arrays, a custom analysis pipeline, and the MEDICC algorithm. We found remarkable diversity of ITGH and evolutionary trajectories in WT. 1q+ is heterogeneous in the majority of tumors with this change, with variable evolutionary timing. We estimate that at least three samples per tumor are needed to detect >95% of cases with 1q+. In contrast, somatic 11p15 LOH is uniformly an early event in WT development. We find evidence of two separate tumor origins in unilateral disease with divergent histology, and in bilateral WT. We also show subclonal changes related to differential response to chemotherapy. Rational trial design to include biomarkers in risk stratification requires tumor multisampling and reliable delineation of ITGH and tumor evolution.

Ultrasound in diagnosis of intrascrotal metastasis of Wilms' tumor: first case report of a Chinese boy and review of the literature

A 31-month-old boy with Wilms' tumor (WT), which primarily had originated from the left kidney, was treated with nephrectomy and adjuvant chemotherapy. 2 months after nephrectomy, a left scrotal mass was found at routine follow-up. High-frequency sonography examination revealed an enlarged left testis with a heterogeneous texture and a hypoechoic solid mass in the left scrotum. Moreover, hypervascular signals presented in both the left testis and the mass on color Doppler flow imaging. Left orchiectomy was performed for suspected intrascrotal metastasis of WT, which was confirmed by histopathology examination. This was the first case of intrascrotal metastasis of WT reported in China with a detailed ultrasound description. Meanwhile, this study also reviewed the comparable diagnostic methods of intrascrotal metastasis of WT found in the English literature.

A rare case of bilateral cystic partially differentiated nephroblastoma recurring as bilateral cystic Wilms tumour

Childhood cystic partially differentiated nephroblastoma (CPDN) is an uncommon renal neoplasm. Bilateral CPDN or CPDN co-existing with a cystic nephroma/Wilms tumour is extremely rare. Treatment of CPDN is by complete surgical excision. Although local recurrences are uncommon, distant metastases have not been described. We present a case of bilateral CPDN that, after complete excision, recurred as bilateral cystic Wilms tumour. To the best of our knowledge, this is the first reported case in the literature where a bilateral CPDN has recurred as bilateral Wilms tumour.

'Primary extrarenal Wilms' tumour': rare presentation of a common paediatric tumour

Wilms' tumour (nephroblastoma), the most common abdominal malignancy of childhood, occurs primarily as a malignant renal tumour. Extrarenal Wilms' tumour is rare with occasional reports from the Indian subcontinent. The various locations of extrarenal Wilms' tumour include retroperitoneum, uterus, skin and thorax. In this report we will discuss the imaging features highlighting the imaging differential diagnosis in a case of retroperitoneal (extrarenal) primary Wilms' tumour.

Correlation between preoperative staging computerized tomography and pathological findings after nodal sampling in children with Wilms tumor

PURPOSE

Guidelines for staging Wilms tumor mandate regional lymph node sampling at nephrectomy. However, the usefulness of preoperative computerized tomography in staging lymph nodes has not been rigorously investigated. Thus, we correlated preoperative computerized tomography and pathological lymph node findings to establish a radiological criterion for pathological lymph node enlargement.

MATERIALS AND METHODS

We reviewed the medical records of children with Wilms tumor at our institution who underwent pre-chemotherapy surgery with lymph node sampling and had preoperative computerized tomography with contrast medium available for interpretation. Computerized tomography was independently reviewed by 2 radiologists blinded to the pathological findings. We collected data on the diameter of the largest regional lymph node identified and this measurement was correlated with the pathological results.

RESULTS

A total of 52 children (25 male, 27 female) with a median age of 3.1 years (range 0.4 to 9.6) were identified. The median largest regional lymph node diameter was 6 mm (range 2 to 15). Of the children 10 (19.2%) had metastatic involvement of sampled lymph nodes. A radiological cutoff of 7 mm for lymph node positivity corresponded to a negative predictive value of 89.0%, a sensitivity of 70.0% and a specificity of 57.1%. A ROC curve was constructed with these data describing the prognostic ability of the diameter of the largest regional lymph node on preoperative computerized tomography to determine lymph node positivity in Wilms tumor, which revealed an AUC of 0.67 (95% CI 0.48-0.87, p = 0.09).

CONCLUSIONS

By defining a radiological size cutoff for suspicious lymph nodes, preoperative computerized tomography for staging lymph nodes in Wilms tumor demonstrates potential clinical usefulness through risk stratification for therapy and future study design.

Clear cell sarcoma of the kidney in children: experience in a developing country

INTRODUCTION

Clear cell sarcoma of the kidney (CCSK) is a rare tumour comprising 4% of primary renal tumours in children. It has a unique constellation of chromosomal and molecular features and should no longer be viewed as an unfavourable histological variant of Wilms tumour. Little is known of its clinical presentation and pathological profile in children living in a developing country.

AIM

To describe the clinical and pathological features of CCSK in children in our practice and to identify factors contributing to poor patient outcomes.

METHOD

A retrospective review of patients with a confirmed diagnosis of CCSK who presented for treatment at a single institution between 1990 and 2008.

RESULTS

14 patients fulfilled the inception criteria. They represented 4% of 356 patients presenting with primary renal tumours during the review period. Clinical and radiological features were indistinguishable from Wilms tumour. Tumours were large (Mean mass 1.4 kg; median 0.9 kg) and metastases were common (42%). Lung and lymph node metastases were more common than skeletal disease. Co-morbidity, particularly hypertension (64%) was common. Initial diagnosis by needle biopsy was correct in only two of seven patients (29%) leading to inappropriate neoadjuvant chemotherapy. Overall survival is poor with 57% of patients alive and disease free from 1 to 7 years off treatment.

CONCLUSION

In a developing country, CCSK is rare and clinically and radiologically indistinguishable from Wilms tumour. Associated hypertension is common. Pretreatment diagnosis is difficult and sampling errors using needle biopsies may be unavoidable. Treatment results are poor and, given the propensity for late recurrence in CCSK, may not be sustained.

A rare case of simultaneous occurrence of Wilms' tumor in the left kidney and the bladder

Wilms' tumor is the most common malignant solid tumor of the kidneys in children. Extrarenal Wilms' tumor is extremely rare. Herein, we report an 8-month-old boy with a chief complaint of frequent micturition and dysuria for 10 days. Physical examination and ultrasonography evaluation revealed simultaneous involvement of neoplasms in the left kidney and the bladder. Following excision of the masses, both were identified as Wilms' tumor by histopathology and immunohistochemistry. The two neoplasms are presumed to have developed independently because of the different pathological manifestation.

[Renal and non-renal tumors within the perirenal space in infants and children: multi-detector row CT characteristics]

OBJECTIVE

To determine the characteristics of Multi-detector Row CT (MDCT) image in distinguishing renal tumors from non-renal tumors within the perirenal space in infants and children.

METHODS

Data from 40 patients with surgically and pathologically proved retroperitoneal neoplasms within the perirenal space were collected. Based on the pathological findings, the patients were divided into renal tumor group (n=14) and non-renal tumor group (n=26). The major clinical characteristics and CT characteristics of the two groups were compared.

RESULTS

Incomplete renal contour with "crescent sign", "beak sign", "embedded kidney sign" and "prominent feeding artery sign" appeared in renal tumors more often than in non-renal tumors (P < 0.05). The sign of "renal displacement and renal axis rotation" and "extra-renal central plane of tumor" appeared more often in non-renal tumors than in renal tumors (P < 0.05). Large solid tumors with "pseudocapsule", "necrosis and cystic change", "vascularity", inferior vena cava tumor thrombus, and distant metastasis were more likely to be renal tumors than non-renal tumors (P < 0.05). Irregular mass with calcifications appeared more often in non-renal tumors than in renal tumors (P < 0.05).

CONCLUSION

MDCT can detect the location, origin and histological feature of retroperitoneal neoplasms in infants and children. The MDCT characteristics can help differentiate renal and non-renal tumors within the perirenal space.

Paraneoplastic Cushing syndrome because of corticotrophin-releasing hormone-secreting Wilms' tumor

A 4-year-old boy with cushingoid appearance and a giant mass on his left kidney was referred to our department. Left nephroureterectomy was performed, and pathologic diagnosis was focal anaplastic nephroblastoma. Based on gradual decrease of postoperative weight, blood pressure, serum adrenocorticotropic hormone, and plasma cortisol levels, paraneoplastic Cushing syndrome because of Wilms' tumor was confirmed. Moreover, through immunohistochemical staining, we confirmed that the Wilms' tumor secreted corticotropin-releasing hormone and caused Cushing syndrome.

Regularized estimation of contrast agent attenuation to improve the imaging of microbubbles in small animal studies

Quantitative analysis of tissue perfusion using contrast-enhanced ultrasound is still limited by shadowing, which is caused by inadequate compensation for microbubble contrast agent attenuation. Many previous methods have been developed for attenuation correction in soft tissues. However, no method has been proposed to correct for microbubble attenuation in vivo. In this article, a model to estimate microbubble attenuation is presented, using the time-intensity variation in a highly echogenic distal area without contrast uptake. This model is based on the assumption that a linear relationship holds between local microbubble attenuation and local backscatter. The model was applied to 12 murine renal perfusion studies. Parametric images of microbubble attenuation were generated, corresponding to dynamic contrast agent-specific sequences without shadowing. Contrast uptake kinetics consistent with the physiology were retrieved in all perfused areas. This method therefore proved to be of potential interest in the quantification of tissue perfusion in small animal studies.

Intra-atrial Extension of Wilms’ Tumor

Echocardiography in a 4-year-old boy, with nephroblastoma of the left kidney, revealed a large homogenous mass in right atrium extending from inferior vena cava, and protruding through tricuspid valve into right ventricle during diastole. Ultrasonography revealed the contiguous spread of the tumor through renal vein with near total caval occlusion. The patient had a fatal outcome before definite treatment could be started. Intracardiac extension of infradiaphragmatic tumors through caval route, although infrequent, can be seen with renal cell carcinoma, Wilms' tumor, hepatoma, lymphoma, and uterine and adrenal tumors. Detection of a mass in right atrium in a child should alert the echocardiographer about the possibility of caval spread from a renal neoplasm.

Renal transplant in a child with bilateral Wilms' tumor national premiere

INTRODUCTION

Bilateral Wilmns' tumors with an unfavorable histology requires a combined treatment (extensive surgery, polychimiotherapy, radiotherapy).

OBJECTIVE

Presentation of the first renal transplant performed in Romania in a child with bilateral Wilms' tumor, at 3 years and 4 months after the end of a multimnodal treatment.

MATERIAL AND METHODS

Patient C. N., born on 30.04.1998, was diagnosed in 04.2001 with right parenchymal renal tumor, polycystic kidney, left cystic renal tumor. 25.04.2001--right radical nephrectomy and partial left upper pole nephrectomy; histopathology examination: triphasic bilateral nephroblastoma, reactive lymph nodes, negative resection edges in the left kidney. 30.04-19.11.2001--polychemotherapy according to the NWTS-5 stages 2-4 focal anaplasia and radiotherapy of the right kidney bed (29.06.2001). 02.2002--a nephrotic syndrome on the remnant kidney which requires its excision and peritoneal dialysis. Abdominal control CT was normal in 03.2005. 11.03.2005- renal transplant from living related donor.

RESULTS

Favorable post-transplant course with normal renal clearance values; at 2 months, normal urography control.

CONCLUSIONS

The tumor pathology does not represent an absolute contraindication for renal transplantation. For the cases with extensive surgery, polychimiotherapy and radiotherapy correctly applied, a pre-transplant "tumor-free" period of at least 2 years is compulsory.

Different CTNNB1 mutations as molecular genetic proof for the independent origin of four Wilms tumours in a patient with a novel germ line WT1 mutation

We describe a patient with a novel WT1 pS50X germ line mutation, who developed bilateral Wilms tumours, both with stromal-type histology. Both tumours showed loss of the wild type WT1 allele (loss of heterozygosity (LOH)) and a tumour specific mutation in catenin beta1 (CTNNB1), S45P in the left and Delta45S in the right tumour. Molecular analysis of microdissected cells from the left tumour revealed the same S45P CTNNB1 mutation in blastema, tubuli, stroma and muscle, and a different CTNNB1 mutation (T41A) in stromal cells isolated from another area of the same slide. Microdissection of two areas of muscle cells from the right tumour revealed the same Delta45S mutation and no CTNNB1 mutation nor LOH of WT1 in normal kidney cells. One year later, the patient developed a new set of bilateral tumours. Both tumours showed LOH of the wild type WT1 allele, but different CTNNB1 mutations as in the first tumours: S45C on the right and S45F on the left side, demonstrating that these developed independently and are not relapses. This case demonstrates the high risk for the development of Wilms tumours in patients with germ line truncation mutations.

Adult Wilms’ tumor: A case report and review of literature

We report the case of a 43-year-old woman with adult Wilms' tumor. Imaging studies confirmed the presence of a 25 x 20 x 12 cm mass in the left kidney. A radical transabdominal nephrectomy was performed. Histological diagnosis was adult Wilms' tumor. Postoperative chemotherapy was offered to the patient who remains disease-free 67 months postoperatively. There are a few reported cases of this entity and till today the best treatment options and the prognosis remain unclear.

Cavectomy for the treatment of Wilms tumor with vascular extension

PURPOSE

Vascular extension to the vena cava occurs in 4% of Wilms tumor cases and can reach the right atrium in up to 1%. When this happens the thrombus is usually not adherent to the vessel wall, and there is blood flow around it. Preoperative chemotherapy can cause thrombus regression and even resolution. If the thrombus persists after chemotherapy, surgery will be a challenge. On the other hand, if the thrombus invades the vessel wall, its removal may not be feasible. In this situation cavectomy is a good surgical strategy because it provides complete resection. The prerequisite for cavectomy is the absence of blood flow in the vena cava on preoperative Doppler ultrasonography. We report 3 cases of Wilms tumor with vena caval invasion in which cavectomy was performed, and discuss the principles, indications and operative technique.

MATERIALS AND METHODS

A total of 171 patients with Wilms tumor were treated at our institution between 1984 and 2004. Of these patients 6 with intravascular extension of thrombus within the right atrium were treated with extracorporeal circulation, cardiac arrest and profound hypothermia, and 3 were treated with cavectomy.

RESULTS

There were no instances of surgical complications or postoperative renal failure in our patients who underwent cavectomy. All remain well and free of disease.

CONCLUSIONS

Cavectomy is a safe procedure for treating pediatric patients with Wilms tumor when there is extension and invasion of the vena cava wall without blood flow.

Perirenal hemorrhage as first presentation of Wilms tumor

Wilms tumor typically presents as an abdominal mass, though occasionally patients present with other manifestations. We report a case of a child presenting with a perirenal hemorrhage and an initially occult Wilms tumor, found only on subsequent renal arteriography. Symptoms in this patient were caused by the presence of perirenal and subcapsular hemorrhage rather than the tumor itself. Despite an unusual presentation, we need to consider underlying neoplasia in children with renal hemorrhage and the absence of a history of trauma. Follow-up studies might help clarify initial negative imaging results.

Cystic partially differentiated nephroblastoma

Cystic partially differentiated nephroblastoma is a relatively rare tumour of the kidney usually affecting infants. Cystic Wilms' tumour and multilocular cystic nephroma should be distinguished from cystic partially differentiated nephroblastoma. Multilocular cystic nephroma is a benign tumour whereas cystic Wilms' tumour is at the malignant end of the range of classification of such tumours. Cystic partially differentiated nephroblastoma may undergo local recurrence but there is no report of metastasis.

[Childhood kidney tumors -- the relevance of imaging]

Kidney tumors represent 6.2% of malignant tumors in children. History, clinical course and radiological findings are necessary elements in the differential diagnosis of the different renal tumors. In the case of nephroblastoma, chemotherapy is based solely on the radiological diagnosis without prior histology. In therapy-optimizing studies of the Society of Pediatric Oncology and Hematology, preoperative chemotherapy is performed. Therapy monitoring is performed in the course of and after preoperative chemotherapy to verify tumor response. Radiological staging plays a significant role in deciding on further treatment and in operative planning. Three-dimensional visualization of the abdominal situs can assist preoperative planning. In summary, diagnostic imaging in renal tumors in children plays a role in differential diagnosis, staging, monitoring of therapy, and surgical planning.

Electron-beam CT as a diagnostic modality in pediatric nephrology and renal transplant surgery

Electron-beam computed tomography is an imaging technology with a variety of medical applications, primarily in cardiology due to its sub-second acquisition time enabling visualization of a beating heart. Recently, this technique has also been introduced into other fields because of lower radiation exposure compared to traditional computed tomography, as well as the strengths of post-procedural three-dimensional visualization. This report evaluates electron-beam computed tomography as a diagnostic modality in pediatric nephrology patients. Seven patients reflecting typical clinical scenarios in pediatric nephrology were reviewed with regard to the value of electron-beam computed tomography and its contribution to the diagnostic workup. Electron-beam computed tomography is noninvasive and allows three-dimensional post-processing, enabling highly accurate images while requiring less radiation and acquisition time. It is very useful for clinical questions that require a detailed description of vascular and renal anatomy.

[Reference radiology in nephroblastoma: accuracy and relevance for preoperative chemotherapy]

PURPOSE

A reference radiologic diagnosis was carried out for the purpose of quality control and in order to achieve high diagnostic accuracy in the ongoing trial and study SIOP 2001/GPOH for renal tumors during childhood. The aim of the present study is to evaluate the value of diagnostic imaging and the benefit of reference evaluation at a pediatric radiology center.

MATERIALS AND METHODS

In 2004 the imaging studies of 97 patients suspected of having a renal tumor were presented at the beginning of therapy. Diagnostic imaging was compared to the primary imaging results and the histological findings and was analyzed in regard to the therapeutic consequence (primary chemotherapy without prior histology). 77 MRI, 35 CT and 67 ultrasound examinations of 47 girls and 50 boys (mean age 4 years; one day to 15.87 years old) were analyzed. In addition to the histological findings, the reference pathological results were submitted in 86 cases. Results from the primary imaging corresponding to the histology and results from the reference radiology corresponding to the histology were statistically compared in a binomial test.

RESULTS

In 76 of the reference-diagnosed Wilms' tumors, 67 were confirmed histologically. In 72 cases preoperative chemotherapy was initiated. In 5 cases neither a Wilms' tumor nor a nephroblastomatosis was found. 16 of 21 cases (76 %) with reference-diagnosed non-Wilms' tumors were selected correctly. The results of the primary imaging corresponded to the histology in 71 cases, and those of the reference radiology in 82 cases. The statistical evaluation showed that the results of the reference radiology were significantly better (p = 0.03971).

CONCLUSION

Reference radiological evaluation improved the diagnostic accuracy with therapeutic relevance. The differentiation of different renal tumors is not completely possible using imaging methods. The rate of patients with false preoperative chemotherapy for all renal neoplasms is currently 5.2 % and 1 % for benign renal tumors.

Visceral larval migrans masquerading as metastatic disease in a toddler with Wilms tumor

A 22-month-old girl with a renal mass had multiple small pulmonary nodules on CT at her initial presentation. After biopsy and neoadjuvant chemotherapy, a Wilms tumor was resected and the pulmonary nodules were shown to have regressed on CT. Follow-up imaging 4 months after initial diagnosis demonstrated multiple new liver lesions and new pulmonary nodules with peripheral eosinophilia. Lung biopsy revealed granuloma formation with prominent eosinophils. The serum antibody titers for Toxocara canis were elevated. This case illustrates that toxocariasis should be considered as a rare differential diagnostic possibility for multiple liver lesions and multifocal peripheral pulmonary opacities in young children with Wilms tumor.

High-frequency ultrasound detection and follow-up of Wilms' tumor in the mouse

The goal of this study was to validate high-frequency (24 MHz) ultrasound imaging techniques for early detection and follow-up of renal tumors in a murine Wilms' tumor model (n = 26). For 11 mice, maximum tumor dimensions were estimated from images along three orthogonal axes for comparison with posteuthanasia caliper and histologic measurements. Tumor size in the 15 remaining mice was checked biweekly. The mice were then euthanized and histologic study assessed tumor position and nature. Tumors were detected in vivo between 7 to 14 days after injection of tumor-inducing cells. Tumor maximum cross-sectional area varied from 0.07 mm2 to 5.7 mm2 at the time of initial detection. The relative r.m.s. error between ultrasonic and histologic estimations of maximum cross-sectional area was estimated to be 19%. Results demonstrate feasibility of noninvasive ultrasound biomicroscopy early detection and characterization of renal tumor development for longitudinal monitoring of the same animal.