Search

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., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Wilms tumor (WT), or nephroblastoma, is the most common primary malignant renal tumor of childhood. It is an embryonal tumor that develops from remnants of immature kidney. There are approximately 500 new WT cases diagnosed in the United States every year. Advances in multimodal therapy including surgery, chemotherapy, and radiation therapy given according to risk stratification have allowed most patients to achieve survival rates in excess of 90%., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Purpose: The majority of children with unilateral renal masses suspicious for malignancy undergo radical nephrectomy, while nephron-sparing surgery is reserved for select cases. We investigated the impact of tumor size on the probability of histology. We hypothesized that pediatric small renal masses are more likely benign or non-Wilms tumor, thus potentially appropriate for nephron-sparing surgery., Materials and Methods: The SEER (Surveillance, Epidemiology, and End Results) database was analyzed for patients aged 0-18 years diagnosed with a unilateral renal mass from 2000-2016. Statistical analysis was performed to help determine a tumor size cut point to predict Wilms tumor and assess the predictive value of tumor size on Wilms tumor histology. Additionally, a retrospective review was performed of patients 0-18 years old who underwent surgery for a unilateral renal mass at a single institution from 2005-2019. Statistical analysis was performed to assess the predictive value of tumor size on final histology., Results: From the SEER analysis, 2,016 patients were included. A total of 1,672 tumors (82.9%) were Wilms tumor. Analysis revealed 4 cm to be a suitable cut point to distinguish non-Wilms tumor. Tumors ≥4 cm were more likely Wilms tumor (OR 2.67, P ≤ .001), but this was driven by the statistical significance in children 5-9 years old. From the institutional analysis, 134 patients were included. Ninety-seven tumors (72.3%) were Wilms tumor. Tumors ≥4 cm had higher odds of being Wilms tumor (OR 30.85, P = .001), malignant (OR 6.75, P = .005), and having radical nephrectomy-appropriate histology (OR 46.79, P < .001)., Conclusions: The probability that a pediatric unilateral renal mass is Wilms tumor increases with tumor size. Four centimeters is a logical cut point to start the conversation around defining pediatric small renal masses and may help predict nephron-sparing surgery-appropriate histology.

The survival of childhood Wilms tumor is currently around 90%, with many survivors reaching reproductive age. Chemotherapy and radiotherapy are established risk factors for gonadal damage and are used in both COG and SIOP Wilms tumor treatment protocols. The risk of infertility in Wilms tumor patients is low but increases with intensification of treatment including the use of alkylating agents, whole abdominal radiation or radiotherapy to the pelvis. Both COG and SIOP protocols aim to limit the use of gonadotoxic treatment, but unfortunately this cannot be avoided in all patients. Infertility is considered one of the most important late effects of childhood cancer treatment by patients and their families. Thus, timely discussion of gonadal damage risk and fertility preservation options is important. Additionally, irrespective of the choice for preservation, consultation with a fertility preservation (FP) team is associated with decreased patient and family regret and better quality of life. Current guidelines recommend early discussion of the impact of therapy on potential fertility. Since most patients with Wilms tumors are prepubertal, potential FP methods for this group are still considered experimental. There are no proven methods for FP for prepubertal males (testicular biopsy for cryopreservation is experimental), and there is just a single option for prepubertal females (ovarian tissue cryopreservation), posing both technical and ethical challenges. Identification of genetic markers of susceptibility to gonadotoxic therapy may help to stratify patient risk of gonadal damage and identify patients most likely to benefit from FP methods., (© 2022 The Authors. International Journal of Cancer published by John Wiley & Sons Ltd on behalf of UICC.)

Background: Pediatric cystic renal lesions are challenging to manage as little is known about their natural course. A modified Bosniak (mBosniak) classification system has been proposed for risk stratification in pediatric patients that takes ultrasound (US) and/or computed tomogram (CT) characteristics into account. However, literature validating this system remains limited., Objective: To determine if the mBosniak classification system correlates with pathologic diagnoses. The hypothesis is that mBosniak classification can stratify the risk of malignancy in children with renal cysts., Study Design: Patients treated for cystic renal masses with available imaging and pathology between 2000 and 2019 from five institutions were identified. Clinical characteristics and pathology were obtained retrospectively. Characteristics from the most recent US, CT, and/or magnetic resonance imaging (MRI) were recorded. Reviewers assigned a mBosniak classification to each scan. mBosniak scores 1/2 were considered low-risk and 3/4 high-risk. These groups were compared with pathology (classified as benign, intermediate, malignant). Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), positive likelihood ratio (+LR), and negative likelihood ratio (-LR) were calculated to assess this categorization as a screening tool to guide surgical intervention. Agreement between imaging modalities was also explored., Results: 99 patients were identified. High-risk imaging findings were correlated with malignant or intermediate pathology with a sensitivity of 88.3%, specificity of 84.6%, PPV of 89.8%, NPV of 82.5%, +LR of 5.7, and -LR of 0.14. The sensitivity for detecting malignant lesions only was 100%. There was substantial agreement between US/CT (n = 55; κ = 0.66) and moderate agreement between US/MRI (n = 20; κ = 0.52) and CT/MRI (n = 13; κ = 0.47)., Discussion: The mBos classification system is a useful tool in predicting the likelihood of benign vs. intermediate or malignant pathology. The relatively high sensitivity and specificity of the system for prediction of high-risk lesions makes this classification applicable to clinical decision making. In addition, all malignant lesions were accurately identified as mBosniak 4 on imaging. This study adds substantial data to the relatively small body of literature validating the mBosniak system for risk stratifying pediatric cystic renal lesions., Conclusions: Pediatric cystic renal lesions assigned mBosniak class 1/2 are mostly benign, whereas class 3/4 lesions are likely intermediate or malignant pathology. We observed that the mBosniak system correctly identified pathology appropriate for surgical management in 88% of cases and did not miss malignant pathologies. There is substantial agreement between CT and US scans concerning mBos classification., Competing Interests: Conflicts of interest None., (Copyright © 2021 Journal of Pediatric Urology Company. Published by Elsevier Ltd. All rights reserved.)

Purpose: Pediatric, adolescent and young adult (PAYA) patients with renal cell carcinoma (RCC) have a high rate of LN involvement, yet data to guide surgical lymph node (LN) management in this group is limited. The objective is to describe a LN yield threshold to quantify the chance of missing occult LN involvement at ≤10% in PAYAs with RCC., Materials & Methods: The National Cancer Database was queried for patients aged ≤30 y with unilateral, non-metastaticRCC from 2004 to 2013. The probability of a false negative LN sampling was determined on the cohort of patients who had at least one positive LNand ≥ 2 LNs examined. For a given LN yield, the probability that a positive LN exists but none were found was estimated using a beta-binomial model., Results: We identified 112 patients meeting study criteria. Median age was 24 y and median tumor size was 9.5 cm (IQR 5.8-14). The median number of LNs sampled was 7 (IQR 4-12) and the median number of LNs positive was 4 (IQR 2-7). To achieve ≤10% probability of a false-negativeLN sampling, the beta-binomial model estimated that 5 LNs (95% CI4-7) must be sampled., Conclusions: The desired LN yield to reduce the risk of a false-negativeLN sampling in PAYAs with RCC to ≤10% is 5. This is in keeping with prior studies identifying a LN yield of 6-10 to achieve the same. These data may be used to standardize surgical guidelines when treating PAYAs with renal tumors., Level of Evidence: II., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Introduction: Management of pediatric renal masses has lagged behind adult paradigms adopting minimally invasive surgery (MIS) and nephron-sparing surgery (NSS). This study investigated national practice patterns between pediatric urologists (PU) and pediatric surgeons (PS) in pediatric renal malignancy., Materials and Methods: The Pediatric National Surgical Quality Improvement Program database was queried for CPT codes for radical/partial nephrectomy from 2012-2017 performed for renal malignancy. Patients were grouped by specialty and operative approach., Results: PU managed 175 (17%) patients while PS managed 811 (77%). PU were more likely to use MIS (14% versus 5%, p < 0.001) and NSS (33% versus 13%, p < 0.001) compared to PS. PS more commonly performed lymph node (LN) sampling/tumor thrombectomy, especially in MIS cases (67% versus 35%, p = 0.008). PS operated on younger patients with higher ASA class compared to PU, but had higher transfusion rates and longer length of stay. Central venous access surgery was more commonly performed on patients operated on by PS, while PU performed more cystoscopy/retrograde pyelography. Patients who underwent NSS compared to radical nephrectomy were less likely to undergo LN sampling, while LN sampling did not differ between open and MIS groups., Conclusions: PU were likely to perform MIS and NSS than PS for pediatric renal masses in this national database. This likely results from inherent training differences between PS and PU and reflects emerging data on safety and efficacy of these advanced surgical techniques. Further investigation into the impact on oncologic and clinical outcomes by surgical specialty and operative approach is necessary.

Background/purpose: While many children with renal tumors require long term venous access (VA) for adjuvant chemotherapy, certainly not all do. This study develops and tests a VA decision tree (DT) to direct the placement of VA in patients with renal tumors., Methods: Utilizing data readily available at surgery a VADT was developed. The VADT was tested retrospectively by 2 independent reviewers on a historic cohort. The ability of the VADT to appropriately select which patients would benefit from VA placement was tested., Results: 160 patients underwent renal tumor surgery between 2005 and 2018. 70 (43.8%) patients met study criteria with median age of 45.1 months (range 1.1-224); 73% required VA. Using the VADT, VA placement was "needed" in 67.1% of patients and "deferred" in 32.9%. Interrater reliability was very high (kappa = 0.97, 95% CI 0.91-1, p < 0.001). The sensitivity and specificity of the VADT to correctly decide on VA placement were 0.92 (0.8-0.98) and 1 (0.79-1). Using the VADT, no patient would have undergone unnecessary VA placement. In reality, 4.3% of patients had an unnecessary VA placed which required a subsequent removal., Conclusions: These preliminary data support the continued study of this VADT to guide intraoperative decisions regarding VA placement in patients with renal tumors., Level of Evidence: III - Study of diagnostic test., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Objective: To review the temporal trends in the published literature of the surgical management of Wilms tumor (WT) relative to surgical modality and authorship by surgeon specialty (pediatric urology [PU] vs pediatric surgery [PS])., Methods: The MEDLINE/PubMed database was queried for manuscripts published by PU or PS including operative management of WT from 1993-2017. After manuscript review, 187 of 2420 studies were included. Studies were compared by author specialty, country of origin, and represented patients., Results: PU published 32% of included publications. The proportion of first author publications by PU increased over time (25% from 1993-2005 to 39% from 2006-2017, P = .029). While PU were first author on 44% of studies in North America, they were relatively underrepresented internationally. PU and PS were equally likely to be first author on cooperative group studies, which accounted for 19% of the overall publications. 14,958 patients underwent extirpative surgery for WT. There was a small increase in publications reporting the use of minimally-invasive surgery (MIS) and nephron-sparing surgery (NSS) over time (<1% and 4% from 1993-2005 to 2% and 7% from 2006-2017, respectively, P <.001). Compared to PS, PU were significantly more likely to publish on patients managed with MIS and NSS (P = .006 and P < 0.001 respectively)., Conclusion: Publications by PU on the surgical management of WT are increasing over time, but are still fewer than PS. PU appeared to be the drivers of the temporal trend towards the increasing use of MIS and NSS in the published literature., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Background: Lymph node (LN) involvement is an important prognostic indicator for patients with Wilms tumor (WT), and there have been previous reports of utilizing LN density (LND = positive LN/LNs examined) as an advanced metric to risk-stratify patients with WT., Objective: The purpose of this study was to describe patient characteristics that affect LN yield and assess the effect of LND on the overall survival (OS) in patients with WT, with the expectation that patients with LNDs above a critical cut-point would demonstrate lower OS., Study Design: The Surveillance, Epidemiology, and End Result (SEER) database was queried for all patients diagnosed with unilateral WT from 2004 to 2015. Patient and disease characteristics were collected, and Poisson regression was used to identify characteristics correlated with LN yield. LND was calculated for LN-positive patients, and multivariable survival analysis was performed, including patient demographics and LND as variables., Results: 1489 patients with unilateral WT were identified for analysis, 231 (15.51%) of whom were LN-positive. Median patient age at diagnosis was three years (IQR 1-5). On Poisson regression, the year of diagnosis, patient age, tumor size and laterality, and stage were found to impact LN yield. For patients with positive LNs, five-year OS of patients with LNDs above 0.4 was worse than those below 0.4 (76.1% vs 89.6%, p = 0.041). On multivariable analysis, tumor size and LND remained significant predictors of OS., Discussion: Administrative databases such as SEER provide an excellent resource for studying conditions where large patient numbers for analysis are difficult to obtain. Unfortunately, the SEER database is unable to account for every factor that could affect LN sampling patterns. Additionally, favorable vs unfavorable histology is not available in SEER, and SEER utilizes its own staging system, which makes comparison to Children's Oncology Group staging difficult. Despite these limitations, the findings of this study are similar to those previously published using administrative databases analyzing LN sampling patterns and the effect of LND on OS in WT., Conclusions: Analysis of the SEER database confirms that there are several patient- and disease-specific factors that affect the number of LNs sampled during nephrectomy for WT, and that LND may be a predictor of OS. These findings highlight the need for standardization of LN sampling patterns for pediatric renal tumors and support the investigation of LND in future studies to further risk-stratify WT patients to tailor therapy intensity., (Copyright © 2019 Journal of Pediatric Urology Company. Published by Elsevier Ltd. All rights reserved.)

Objective: To describe and compare the management of WT and oncologic outcomes by patient age using a large national database., Methods: The National Cancer Database was queried for patients with WT diagnosis from 2004 to 2013. Patients were grouped by age and compared: pediatric (<16 years), young adults (16-35 years) and adult (>35 years). Overall survival (OS) was the primary endpoint. Factors associated with OS were determined using multivariate analysis., Results: The majority of patients were pediatric (n = 2686), followed by young adult (n = 91), and adult (n = 35). Five-year OS was significantly better for children vs young adults or adults (93.1% vs 79.1% vs 78.9%, respectively; P <.001), as was 10-year OS (91.5% vs 52.4% vs 70%; P <.001). On multivariate analysis, OS was significantly better for children vs young adult (HR 3.62; 95% CI 2.25-5.8; P <.001), and adult (HR 3.38; 95% CI, 1.49-7.7; P <.004). Other variables associated with worse OS included bilateral disease (HR 2.06; P = .003), stage II disease (HR 2.92; P = .036), stage IV disease (HR 4.1; P = .004), and positive lymph nodes (HR 1.97-4.90; P = .018). Patients >15 years were less likely to undergo lymph node sampling (OR 0.19; P <.001), radiation therapy (OR 0.62; P = .03), or chemotherapy (OR 0.38; P <.001)., Conclusion: Adults with WT experience worse 5- and 10-year OS when compared to children with WT. Survival decrements in adults are likely multifactorial including modifiable factors such as inadequate staging due to low rates of lymph node sampling, and underutilization of adjuvant therapies., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Purpose: Current investigational priorities in the treatment of favorable histology Wilms tumor (FHWT) center on accurate staging and risk-stratification. The extent of lymph node (LN) sampling has not been clearly defined; its importance cannot be overstated as it guides adjuvant therapy. The identification of a minimum LN yield to minimize the risk of harboring occult metastatic disease could help development of surgical guidelines. This study focuses on using the beta-binomial distribution to estimate the risk of occult metastatic disease in patients with FHWT., Materials & Methods: The National Cancer Database was queried for patients with unilateral FHWT from 2004 to 2013. Data were used to characterize nodal positivity for patients who underwent surgery and had ≥1 positive LN and ≥2 LNs examined. The probability of missing a positive LN (i.e., false negative) for a given LN yield was calculated using an empirical estimation and the beta-binomial model. Patients were then stratified by tumor size., Results: 422 patients met study criteria. To limit the chance of missing a positive LN to ≤10%, the empirical estimation and beta-binomial model estimated that 6 and 10 LNs needed to be sampled, respectively. Tumor size did not influence the result. Internal validation showed little variation to maintain a false negative rate ≤ 10%., Conclusions: Using mathematical modeling, it appears that the desired LN yield in FHWT to reduce the risk of false-negative LN sampling to ≤10% is between 6 and 10. The current analysis represents an objective attempt to determine the desired surgical approach to LN sampling to accurately stage patients with FHWT., Level of Evidence: II., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Objective: To present the surgical approach to a multifocal Wilms tumor found on screening ultrasound in an asymptomatic 2-year-old female., Materials: A 2-year-old female with hemihypertrophy underwent screening imaging every 3 months with renal ultrasound. A solitary, incidental renal mass was detected. Physical exam was unremarkable except for left leg hemihypertrophy. Laboratory workup was largely normal other than an elevated lactate dehydrogenase. Staging imaging revealed multiple masses on the right kidney and a normal left kidney. There were no distant metastases. The most likely diagnosis was Wilms tumor. After receiving chemotherapy for 6 weeks, imaging revealed an excellent response to chemotherapy and surgery was performed., Results: The patient underwent open partial nephrectomy of the 3 tumors on the right. Prior to beginning, cystoscopy and ureteral stent placement was performed as it was felt the collecting system would likely be entered during resection. The renal hilum was not clamped throughout this resection and manual parenchymal compression was used to minimize global ischemia. Retroperitoneal lymph node dissection was also performed. The patient recovered well and was discharged home 5 days after surgery. Her stent was removed at home without complications. Final pathology revealed nephrogenic rests with all 7 lymph nodes were negative for malignancy., Conclusion: Management of multifocal, unilateral Wilms tumor with open partial nephrectomy after neoadjuvant chemotherapy is an important part of protocol management for patients with Wilms tumor with predisposition syndromes., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Objective: To present the surgical approach to a cystic renal mass suspicious for malignancy in a 22-month-old female., Materials: The patient was a healthy female was found to have an abdominal mass by her parents. Her mother underwent a nephrectomy as a child for unknown pathology. Physical examination was otherwise unremarkable and laboratory workup was normal. Imaging workup revealed a large cystic renal mass suspicious for malignancy. Surgical resection was planned., Results: A nonsyndromic 22-month-old female underwent open radical nephrectomy on the left with regional lymph node dissection. A transverse abdominal incision was used, followed by medial reflection of the colon and complete renal mobilization. The distal ureter and renal vasculature were identified and controlled and the kidney removed. A retractor was then assembled and regional lymph node dissection performed. Final pathology was cystic nephroma with 10 benign lymph nodes. The patient recovered well and was discharged home 3 days after surgery., Conclusion: Open radical nephrectomy is an important part of protocol management for patients with renal masses suspicious for malignancy., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Due to the rarity of Wilms tumor (WT) and the relative urgency with which pediatric renal tumors are treated, there is little reported data on the natural history and growth of WTs. Historical reports of estimated doubling times of WTs were based on time to disease recurrence after initial diagnosis and treatment, and were published before the current advancements in molecular biomarker testing. We compare 2 cases of WT with sequential imaging, and postulate how the growth parameters of these tumors may be associated with differing chromosomal traits., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Adult Wilms tumor (WT) is a well-known, albeit rare entity and has historically been associated with worse overall clinical outcomes when compared to younger patients. Because WT is uncommon in adult patients, it is often misdiagnosed and treated off standardized pediatric protocols. WT associated with pregnancy is even more rare, and there is not a standardized approach to this small subset of patients. We present a case of an adult WT discovered and managed during the perinatal period and review prior published cases., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Objective: To identify factors impacting overall survival (OS) in children, adolescents, and young adults with high-risk renal tumors (HRRTs)., Methods: The National Cancer Database was queried for patients ≤30 years old diagnosed with anaplastic Wilms tumors (AWT), clear cell sarcoma of the kidney (CCSK), or rhabdoid tumor of the kidney (RTK) between 2004 and 2013. Demographic, clinical, and OS data were abstracted. OS between groups was compared with a Kaplan-Meier curve. Univariate and multivariate survival analyses were performed., Results: A total of 349 patients were identified meeting criteria; 133 (38.1%) AWT, 120 (34.4%) CCSK, and 96 (27.5%) RTK. Patients with RTK were less likely to undergo surgery than those with AWT or CCSK (77.1% vs 94% vs 99%, P < .001) and less likely to receive chemotherapy (84.4% vs 96.2% vs 95%, P = .013) or radiation (52.1% vs 81.2% vs 86.7%, P < .001). Estimated 5-year OS was 76.1% (95% confidence interval [CI] 67.9-84.4) for AWT, 92.7% (95% CI 87.4-97.9) for CCSK, and 33.5% (95% CI 23.1-43.9) for RTK (P < .001). On multivariate analysis, AWT (HR 3.372, P = .032) and RTK histology (HR 12.595, P < .001) were significantly associated with worse OS, while receiving radiation (HR 0.43, P = .006) was associated with improved OS. LN positivity, margin status, and undergoing surgery were not. Analyzing the HRRTs individually, for AWT, undergoing surgery was associated with OS (HR 0.308, P = .031). For RTK, factors associated with OS included undergoing surgery (HR 0.209, P = .007) and radiation (HR 0.411, P = .008)., Conclusion: Within the HRRTs, RTK is associated with worse outcomes than either AWT or CCSK. Receiving radiation is significantly associated with improved outcomes, and surgery is important for those with AWT and RTK., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Purpose: We characterize and apply the modified Bosniak classification system to a cohort of children with cystic renal lesions and known surgical pathology., Materials and Methods: We identified all patients at our institution with cystic renal masses who also underwent surgery for these lesions. Patients without available preoperative imaging or pathology were excluded. All radiological imaging was independently reviewed by a pediatric radiologist blinded to pathological findings. Imaging characteristics (size, border, septations, calcifications, solid components, vascularity) were recorded from the most recent preoperative ultrasounds and computerized tomograms. The modified Bosniak classification system was applied to these scans and then correlated with final pathology., Results: A total of 22 patients met study criteria. Median age at surgery was 6.1 years (range 11 months to 16.8 years). Of the patients 12 (54.5%) underwent open nephrectomy, 6 (27.3%) open partial nephrectomy, 2 (9.1%) laparoscopic cyst decortication, 1 (4.5%) open renal biopsy and 1 (4.5%) laparoscopic partial nephrectomy. Final pathology was benign in 9 cases (41%), intermediate in 6 (27%) and malignant in 7 (32%). All malignant lesions were modified Bosniak class 4, all intermediate lesions were modified class 3 or 4 and 8 of 9 benign lesions (89%) were modified class 1 or 2., Conclusions: Cystic renal lesions in children with a modified Bosniak class of 1 or 2 were most often benign, while class 3 or 4 lesions warranted surgical excision since more than 90% of masses harbored intermediate or malignant pathology. The modified Bosniak classification system appears to allow for a reasonable clinical risk stratification of pediatric cystic renal masses., (Copyright © 2018 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.)

Purpose: Current Children's Oncology Group studies on renal malignancy focus on minimizing treatment side effects with a goal of decreasing long-term complications. In this series we evaluate the patterns of initial imaging in children with renal tumors., Materials and Methods: We retrospectively reviewed records of 122 patients treated for renal tumors at our institution between 2005 and 2016. Ideal imaging was defined as cross-sectional imaging of the chest, abdomen and pelvis in a single setting without any additional ionizing radiation exposing scans., Results: Median patient age was 33.5 months (range 1 to 195). A total of 101 patients (83%) were initially evaluated elsewhere and subsequently referred to oncology (67.2%) for further evaluation. Before treatment 58 patients (47.5%) underwent imaging that was obtained in an ideal manner. Compared to those undergoing ideal imaging, median additional radiation exposure was 2.31 mSv (range 0.9 to 11.5), 3.08 mSv (0.6 to 11.7) and 5.1 mSv (1.2 to 16) in patients younger than 5 years, 5 to 9 years old and 10 years or older, respectively. Factors associated with undergoing ideal imaging included undergoing abdominal ultrasound as an initial scan (OR 3.637, p = 0.001), while presentation to an emergency department resulted in a reduced likelihood of undergoing ideal imaging (OR 0.351, p = 0.012). Factors associated with a decreased likelihood of undergoing initial screening ultrasound included presenting with vague symptoms (OR 0.072, p = 0.045) and presenting to a tertiary care emergency department (OR 0.228, p = 0.027)., Conclusions: Current patterns of initial imaging for pediatric renal tumors are often associated with unnecessary and avoidable imaging studies, resulting in increased radiation exposure. Presenting to the emergency room as the initial point of contact with vague symptoms is associated with a decreased likelihood of undergoing appropriate or ideal pretherapy imaging, while initial evaluation with ultrasound is associated with a greater likelihood of undergoing ideal imaging, reducing overall radiation exposure. We advocate initial abdominal ultrasound in all pediatric patients suspected of having an abdominal mass. Our data highlight an opportunity for quality improvement across specialties caring for children with renal tumors., (Copyright © 2018 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.)

Introduction: Anecdotally, renal tumor (RT) surgery makes up a limited portion of the practice for most pediatric urologists and pediatric surgeons. Data are lacking on the current perceptions of RT surgery, both volume of surgery and issues related to surgical practice, among pediatric surgeons (PS) and pediatric urologists (PU)., Objectives: To describe practice patterns of pediatric renal tumor (RT) surgery and identify factors related to higher reported volumes of RT surgery., Study Design: The survey was developed and pilot-tested by the Children's Oncology Group (COG) RT surgery committee. The survey was distributed to APSA and SPU members. Logistic regression was performed to correlate surgeon-reported factors with higher reported volumes of RT surgery., Results: The survey was sent to 1,282 APSA and 426 SPU members, 367 (21.5%) surveys were completed from eligible responders, 244 (65.2%) and 123 (32.9%) from APSA and SPU invitations, respectively. Overall, 33.9% reported being part of a practice group in which RT surgical care is sub-specialized. A majority (50.7%) of respondents reported personally performing one to two RT surgeries annually, and 16.7% reported performing none. Multivariate logistic regression identified the following significant factors associated with increased individual RT surgical volume: group sub-specialization, COG/SIOP membership, regular tumor board attendance, and annual institutional volume >10 RT surgeries (Table). Accurate responses on the need for lymph node (LN) sampling in RT surgery were reported by 89.9%. Overall, 15.8% and 24.5% of respondents failed to correctly correlate local stage III disease in Wilms tumor (WT) with open or percutaneous biopsy, respectively (p < 0.001)., Discussion: While we found that reported RT surgery volume is low among both pediatric urologists and surgeons, we did identify surgeon-specific factors which correlated with higher RT surgical volume. Interested pediatric urologists and surgeons may use these data to tailor their practice if their goal is to increase RT surgery volume. Additionally, based on less than ideal rates of correct responses to nuance in the staging and treatment of WT, there are clear opportunities to increase education in this content area. However, the study is limited by use of a non-validated survey instrument and the relatively low response rates., Conclusion: Reported individual RT surgery volume is low. Factors associated with increased volume include sub-specialty practice, tumor board involvement, and higher institutional volume. Responses on LN sampling and biopsy in WT demonstrate opportunities for educational initiatives., (Copyright © 2017 Journal of Pediatric Urology Company. Published by Elsevier Ltd. All rights reserved.)

Metanephric adenoma is a rare pediatric renal tumor, generally considered to be benign. It can be difficult to distinguish from Wilms tumor and renal cell carcinoma based on imaging alone, and even may be difficult on histopathologic analysis. We present a case of a large cystic metanephric adenoma managed with surgical resection. This case highlights the difficulty in managing cystic renal lesions in children and adolescents as there is a paucity of data on the radiologic and pathologic correlation in such patients., (Copyright © 2016 Elsevier Inc. All rights reserved.)