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Purpose: Accurate measurement of renal mass size is crucial in the management of renal cancer. With the burdensome cost of imaging yet its need for management, a better understanding of the variability among patients when determining mass size remains of urgent importance. Current guidelines on optimal imaging are limited, especially with respect to body mass index (BMI). The aim of this study is to discern which modalities accurately measure renal mass size and whether BMI influences such accuracy. Methods: A multi-institutional chart review was performed for adult patients undergoing partial or radical nephrectomy between 2018 and 2021, with 236 patients ultimately included. Patients were categorized by BMI (BMI 1: 18.5–24.9, BMI 2: 25–29.9, BMI 3: 30–34.9, and BMI 4: ≥ 35). The greatest mass lengths were compared between the pathology report and the following: computerized tomography (CT), renal ultrasound, and magnetic resonance imaging (MRI). Results: The difference between greatest length on CT with contrast and MRI were significantly different when compared to pathologic measurement. BMI groups 3 and 4 were found to have a significant difference in size estimates compared to BMI 2 for CT with contrast. No difference was found between size estimates by BMI group for any other imaging modality. Conclusion: CT with contrast becomes less accurate at estimating mass size for patients with BMI > 30. While contrast-enhanced CT remains a vital imaging modality for tissue enhancement in the context of unknown renal masses, caution must be used for mass size estimation in the obese population. [ABSTRACT FROM AUTHOR]

Background: The incidence of renal tumors has steadily increased over the past decade. In this study, the authors performed a systematic review and analysis of the literature on renal fine‐needle aspiration (FNA) to determine its performance and explore whether a standardized classification system can be used for reporting renal FNA cytology. Methods: A systematic search of published articles on renal FNA was conducted. The data on FNA and histologic diagnosis were extracted and categorized, and the risk of malignancy was calculated. Different scenarios were used to estimate FNA performance statistics. Results: Of the 3766 potentially relevant studies, 23 met the inclusion criteria of the study. The 2231 FNA cases included were re‐categorized according to the classification system, rendering 142 (6.36%) nondiagnostic, 270 (12.1%) nonneoplastic, 271 (12.14%) benign neoplasm, 65 (2.91%) renal neoplasm with unknown malignant potential, oncocytic type, 25 (1.12%) atypia of undetermined significance, 60 (2.68%) suspicious for malignancy, and 1398 (62.66%) malignant FNA diagnoses. The risk of malignancy in these cases was 65.4%, 18.1%, 16.6%, 16.9%, 60%, 73.3%, and 96.9%, respectively. According to the classification system, the study indicated that the accuracy of renal FNA was between 91% and 95%, the sensitivity was 90.9%–96.7%, and the specificity was 82%–92% in different scenarios. Conclusions: There is a need for a standardized reporting in renal cytology that will improve the sensitivity and accuracy of renal cytology, reduce the rate of indeterminate diagnoses, and alter the management strategies of renal lesions. Based on the available literature, a new reporting system is proposed, including categories with an associated risk of malignancy. The authors performed a systematic review and analysis of all available literature on kidney fine‐needle aspiration to determine its accuracy and explore whether a standardized classification system could be used for reporting renal fine‐needle aspiration cytology. The findings indicate that standardization will improve the sensitivity and accuracy of renal cytology, reduce the rate of indeterminate diagnoses, improve the communication between pathologists and clinicians, and change the management strategies for patients who have renal lesions. [ABSTRACT FROM AUTHOR]

Key Clinical Message: In the context of lymphoma, it is of paramount importance to perform subsequent Positron Emission Tomography‐Computed Tomography (PET‐CT) scans to ensure the comprehensive eradication of neoplasms. Primary renal diffuse tumors constitute less than 1% of all renal neoplasms. Among these, diffuse renal large B‐cell lymphoma is an exceedingly rare extranodal lymphoma. A 64‐year‐old male presented to the Department of Urology with complaints of persistent left flank discomfort for a duration of 2 weeks. Additionally, he reported generalized weakness, fatigue, and symptoms indicative of lower urinary tract obstruction, such as discomfort in the left testicle and dysuria. Ultrasound imaging revealed an echogenic structure with thickened, reactive walls and a turbid fluid core, located in the left flank, proximal to the lower pole of the kidney. This structure was subsequently identified as diffuse renal large B‐cell lymphoma. For the diagnosis of large B‐cell lymphomas, it is imperative that a proficient hematopathologist performs a comprehensive examination of the tumor tissue, preferably utilizing an excisional biopsy. The categorization of lymphoma requires specialized tests such as immunohistochemistry, flow cytometry, fluorescence in situ hybridization (FISH), and molecular testing. In instances where a renal mass is detected, healthcare professionals should consider performing a biopsy. In lymphoma cases, follow‐up Positron Emission Tomography‐Computed Tomography (PET‐CT) scans are crucial to confirm the complete eradication of the tumor. [ABSTRACT FROM AUTHOR]

Objectives: To evaluate radiomics features' reproducibility using inter-package/inter-observer measurement analysis in renal masses (RMs) based on MRI and to employ machine learning (ML) models for RM characterization. Methods: 32 Patients (23M/9F; age 61.8 ± 10.6 years) with RMs (25 renal cell carcinomas (RCC)/7 benign masses; mean size, 3.43 ± 1.73 cm) undergoing resection were prospectively recruited. All patients underwent 1.5 T MRI with T2-weighted (T2-WI), diffusion-weighted (DWI)/apparent diffusion coefficient (ADC), and pre-/post-contrast-enhanced T1-weighted imaging (T1-WI). RMs were manually segmented using volume of interest (VOI) on T2-WI, DWI/ADC, and T1-WI pre-/post-contrast imaging (1-min, 3-min post-injection) by two independent observers using two radiomics software packages for inter-package and inter-observer assessments of shape/histogram/texture features common to both packages (104 features; n = 26 patients). Intra-class correlation coefficients (ICCs) were calculated to assess inter-observer and inter-package reproducibility of radiomics measurements [good (ICC ≥ 0.8)/moderate (ICC = 0.5–0.8)/poor (ICC < 0.5)]. ML models were employed using reproducible features (between observers and packages, ICC > 0.8) to distinguish RCC from benign RM. Results: Inter-package comparisons demonstrated that radiomics features from T1-WI-post-contrast had the highest proportion of good/moderate ICCs (54.8–58.6% for T1-WI-1 min), while most features extracted from T2-WI, T1-WI-pre-contrast, and ADC exhibited poor ICCs. Inter-observer comparisons found that radiomics measurements from T1-WI pre/post-contrast and T2-WI had the greatest proportion of features with good/moderate ICCs (95.3–99.1% T1-WI-post-contrast 1-min), while ADC measurements yielded mostly poor ICCs. ML models generated an AUC of 0.71 [95% confidence interval = 0.67–0.75] for diagnosis of RCC vs. benign RM. Conclusion: Radiomics features extracted from T1-WI-post-contrast demonstrated greater inter-package and inter-observer reproducibility compared to ADC, with fair accuracy for distinguishing RCC from benign RM. Clinical relevance: Knowledge of reproducibility of MRI radiomics features obtained on renal masses will aid in future study design and may enhance the diagnostic utility of radiomics models for renal mass characterization. [ABSTRACT FROM AUTHOR]

Objective: To automate the generation of three validated nephrometry scoring systems on preoperative computerised tomography (CT) scans by developing artificial intelligence (AI)‐based image processing methods. Subsequently, we aimed to evaluate the ability of these scores to predict meaningful pathological and perioperative outcomes. Patients and Methods: A total of 300 patients with preoperative CT with early arterial contrast phase were identified from a cohort of 544 consecutive patients undergoing surgical extirpation for suspected renal cancer. A deep neural network approach was used to automatically segment kidneys and tumours, and then geometric algorithms were used to measure the components of the concordance index (C‐Index), Preoperative Aspects and Dimensions Used for an Anatomical classification of renal tumours (PADUA), and tumour contact surface area (CSA) nephrometry scores. Human scores were independently calculated by medical personnel blinded to the AI scores. AI and human score agreement was assessed using linear regression and predictive abilities for meaningful outcomes were assessed using logistic regression and receiver operating characteristic curve analyses. Results: The median (interquartile range) age was 60 (51–68) years, and 40% were female. The median tumour size was 4.2 cm and 91.3% had malignant tumours. In all, 27% of the tumours were high stage, 37% high grade, and 63% of the patients underwent partial nephrectomy. There was significant agreement between human and AI scores on linear regression analyses (R ranged from 0.574 to 0.828, all P < 0.001). The AI‐generated scores were equivalent or superior to human‐generated scores for all examined outcomes including high‐grade histology, high‐stage tumour, indolent tumour, pathological tumour necrosis, and radical nephrectomy (vs partial nephrectomy) surgical approach. Conclusions: Fully automated AI‐generated C‐Index, PADUA, and tumour CSA nephrometry scores are similar to human‐generated scores and predict a wide variety of meaningful outcomes. Once validated, our results suggest that AI‐generated nephrometry scores could be delivered automatically from a preoperative CT scan to a clinician and patient at the point of care to aid in decision making. [ABSTRACT FROM AUTHOR]

Objective: To evaluate a recently proposed CT-based algorithm for diagnosis of clear-cell renal cell carcinoma (ccRCC) among small (≤ 4 cm) solid renal masses diagnosed by renal mass biopsy. Methods: This retrospective study included 51 small renal masses in 51 patients with renal-mass CT and biopsy between 2014 and 2021. Three radiologists independently evaluated corticomedullary phase CT for the following: heterogeneity and attenuation ratio (mass:renal cortex), which were used to inform the CT score (1–5). CT score ≥ 4 was considered positive for ccRCC. Diagnostic accuracy was calculated for each reader and overall using fixed effects logistic regression modelling. Results: There were 51% (26/51) ccRCC and 49% (25/51) other masses. For diagnosis of ccRCC, area under curve (AUC), sensitivity, specificity, and positive predictive value (PPV) were 0.69 (95% confidence interval 0.61–0.76), 78% (68–86%), 59% (46–71%), and 67% (54–79%), respectively. CT score ≤ 2 had a negative predictive value 97% (92–99%) to exclude diagnosis of ccRCC. For diagnosis of papillary renal cell carcinoma (pRCC), CT score ≤ 2, AUC, sensitivity, specificity, and PPV were 0.89 (0.81–0.98), 81% (58–94%), 98% (93–99%), and 85% (62–97%), respectively. Pooled inter-observer agreement for CT scoring was moderate (Fleiss weighted kappa = 0.52). Conclusion: The CT scoring system for prediction of ccRCC was sensitive with a high negative predictive value and moderate agreement. The CT score is highly specific for diagnosis of pRCC. Clinical relevance statement: The CT score algorithm may help guide renal mass biopsy decisions in clinical practice, with high sensitivity to identify clear-cell tumors for biopsy to establish diagnosis and grade and high specificity to avoid biopsy in papillary tumors. Key Points: • A CT score ≥ 4 had high sensitivity and negative predictive value for diagnosis of clear-cell renal cell carcinoma (RCC) among solid ≤ 4-cm renal masses. • A CT score ≤ 2 was highly specific for diagnosis of papillary RCC among solid ≤ 4-cm renal masses. • Inter-observer agreement for CT score was moderate. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the diagnostic performance of contrast-enhanced (CE) ultrasound using Sonazoid (SNZ–CEUS) by comparing with contrast-enhanced computed tomography (CE–CT) and contrast-enhanced magnetic resonance imaging (CE–MRI) for differentiating benign and malignant renal masses. Materials and methods: 306 consecutive patients (from 7 centers) with renal masses (40 benign tumors, 266 malignant tumors) diagnosed by both SNZ–CEUS, CE–CT or CE–MRI were enrolled between September 2020 and February 2021. The examinations were performed within 7 days, but the sequence was not fixed. Histologic results were available for 301 of 306 (98.37%) lesions and 5 lesions were considered benign after at least 2 year follow-up without change in size and image characteristics. The diagnostic performances were evaluated by sensitivity, specificity, positive predictive value, negative predictive value, and compared by McNemar's test. Results: In the head-to-head comparison, SNZ–CEUS and CE–MRI had comparable sensitivity (95.60 vs. 94.51%, P = 0.997), specificity (65.22 vs. 73.91%, P = 0.752), positive predictive value (91.58 vs. 93.48%) and negative predictive value (78.95 vs. 77.27%); SNZ–CEUS and CE–CT showed similar sensitivity (97.31 vs. 96.24%, P = 0.724); however, SNZ–CEUS had relatively lower than specificity than CE–CT (59.09 vs. 68.18%, P = 0.683). For nodules > 4 cm, CE–MRI demonstrated higher specificity than SNZ–CEUS (90.91 vs. 72.73%, P = 0.617) without compromise the sensitivity. Conclusions: SNZ–CEUS, CE–CT, and CE–MRI demonstrate desirable and comparable sensitivity for the differentiation of renal mass. However, the specificity of all three imaging modalities is not satisfactory. SNZ–CEUS may be a suitable alternative modality for patients with renal dysfunction and those allergic to gadolinium or iodine-based agents. Key Points: This prospective multicenter study demonstrated that the diagnostic performance of SNZ–CEUS was comparable to CE–CT and CE–MRI. The three imaging modalities displayed desirable sensitivity, while the specificity needs to be further improved. CE–MRI may have better specificity than SNZ–CEUS for differentiating renal masses bigger than 4 cm [ABSTRACT FROM AUTHOR]

Biopsy of benign and low‐risk tumors of the kidney can be grouped into three distinct categories with different levels of risk, and the suggested diagnoses of these tumors should be tailored to their respective category. [ABSTRACT FROM AUTHOR]

Image-guided ablation (IGA) is a rapidly developing field in interventional oncology. There is some evidence suggesting IGA's non-inferiority compared with partial or radical nephrectomy for the treatment of small renal masses (SRM). However, these are mostly limited to retrospective cohort studies. This review article outlines the evidence comparing IGA to partial nephrectomy by collating the different survival measures and evaluates the challenges of producing clinical trials and high-quality evidence. The main challenges are due to the heterogeneity of SRM, patient selection bias, unstandardized endpoint and outcomes, and the lack of global practice standards. Despite the evidence thus far demonstrating that IGA stands as a non-inferior treatment modality for SRMs, exhibiting favorable short- and long-term outcomes, further robust research is needed to integrate ablation techniques into routine clinical practice with a multidisciplinary approach. There is emerging evidence that suggests randomized controlled trial in SRMs is possible, and technologies such as histotripsy as well as artificial intelligence are used in IGA. [ABSTRACT FROM AUTHOR]

Xanthogranulomatous pyelonephritis (XGP) is an extremely rare, chronic granulomatous inflammatory condition thought to arise secondary to a combination of obstruction, recurrent bacterial infection and an incomplete immune response although the etiology of XGP is more complex. We would like to report a case of XGP occurring in a patient with polycystic kidney disease (PCKD), which has not been previously documented in etiology. A 29-year-old woman presented to our hospital with right upper quadrant pain for 5 days. She had experienced a low-grade fever, generalized weakness, and myalgia throughout her body for 2 weeks. She had no history of renal stones or recurrent UTIs. Contrast-enhanced CT revealed a well-enhancing large septated cystic mass in the right kidney and numerous cysts in the liver and both kidneys. Open right radical nephrectomy was performed due to the suspicion of renal cell carcinoma, as there was no response to antibiotics over 7 days. Gross specimen demonstrated architectural distortion due to xanthomatous nodules and a dilated pelvico-calyceal system filled with pus and blood. Microscopic examination revealed infiltration of neutrophils and lipid-laden macrophages. The patient is currently being followed up in the outpatient clinic without recurrence of XGP. This is the first reported case of XGP in a patient with underlying PCKD. Physicians should consider PCKD as a potential underlying cause of XGP.

Key Clinical Message In the context of lymphoma, it is of paramount importance to perform subsequent Positron Emission Tomography‐Computed Tomography (PET‐CT) scans to ensure the comprehensive eradication of neoplasms. Abstract Primary renal diffuse tumors constitute less than 1% of all renal neoplasms. Among these, diffuse renal large B‐cell lymphoma is an exceedingly rare extranodal lymphoma. A 64‐year‐old male presented to the Department of Urology with complaints of persistent left flank discomfort for a duration of 2 weeks. Additionally, he reported generalized weakness, fatigue, and symptoms indicative of lower urinary tract obstruction, such as discomfort in the left testicle and dysuria. Ultrasound imaging revealed an echogenic structure with thickened, reactive walls and a turbid fluid core, located in the left flank, proximal to the lower pole of the kidney. This structure was subsequently identified as diffuse renal large B‐cell lymphoma. For the diagnosis of large B‐cell lymphomas, it is imperative that a proficient hematopathologist performs a comprehensive examination of the tumor tissue, preferably utilizing an excisional biopsy. The categorization of lymphoma requires specialized tests such as immunohistochemistry, flow cytometry, fluorescence in situ hybridization (FISH), and molecular testing. In instances where a renal mass is detected, healthcare professionals should consider performing a biopsy. In lymphoma cases, follow‐up Positron Emission Tomography‐Computed Tomography (PET‐CT) scans are crucial to confirm the complete eradication of the tumor.

BackgroundSmall renal mass (SRM) biopsy remains under-utilized due to stigma. Meanwhile, the alarmingly high benign findings in resected kidney masses highlight the need for improved preoperative diagnosis and patient selection.MethodsThe purpose of this study is to review the success rate of SRM biopsy and to evaluate its impact on patient management. A total of 168 percutaneous image-guided core needle biopsies (CNBs) of SRMs were retrieved at a tertiary academic center between 2015 and 2019. Subsequent treatment choices, side effects and outcomes were retrospectively reviewed.ResultsThe diagnostic rate of CNB was 86.9%. Benign neoplasms accounted for a significant portion (14.3%) of SRM. Renal cell carcinomas (RCCs) were the most common diagnoses (69.6%) as expected. In biopsy-resection correlation, the positive predictive value of CNB was 100%. Tumor typing and subtyping by CNB were highly accurate, 100% and 98.3% respectively. Nuclear grading for clear cell RCC was accurate in 83.8% cases. The CNB results had significant impact on treatment. Most patients with RCCs underwent either resection (54.1%) or ablation (33.9%), in contrast to observation in benign neoplasms (90.5%). Most importantly, the benign resection rate (3.2%) in this series was much lower than the national average.ConclusionCNB provided accurate diagnoses for the majority of SRMs and revealed benign diagnoses in a subset of clinically suspicious lesions. Employment of CNB in suspicious SRM may help avoid overtreatment for benign lesions.

Objectives: To evaluate the applicability of Bosniak 2019 criteria on a monophasic portal venous phase using rapid kilovoltage-switching DECT (rsDECT). Materials and methods: One hundred twenty-seven renal masses assessed on rsDECT were included, classified according to Bosniak 2019 classification using MRI as the reference standard. Using the portal venous phase, virtual monochromatic images at 40, 50, and 77 keV; virtual unenhanced (VUE) images; and iodine map images were reconstructed. Changes in attenuation values between VUE and 40 keV, 50 keV, and 77 keV measurements were computed and respectively defined as ∆HU40keV, ∆HU50keV, and ∆HU77keV. The values of ∆HU40keV, ∆HU50keV, and ∆HU77keV thresholds providing the optimal diagnostic performance for the detection of internal enhancement were determined using Youden index. Results: Population study included 25 solid renal masses (25/127, 20%) and 102 cystic renal masses (102/127, 80%). To differentiate solid to cystic masses, the specificity of the predefined 20 HU threshold reached 88% (95%CI: 82, 93) using ∆HU77keV and 21% (95%CI: 15, 28) using ∆HU40keV. The estimated optimal threshold of attenuation change was 19 HU on ∆HU77keV, 69 HU on ∆HU50eV, and 111 HU on ∆HU40eV. The rsDECT classification was highly similar to that of MRI for solid renal masses (23/25, 92%) and for Bosniak 1 masses (62/66, 94%). However, 2 hyperattenuating Bosniak 2 renal masses (2/26, 8%) were classified as solid renal masses on rsDECT. Conclusion: DECT is a promising tool for Bosniak classification particularly to differentiate solid from Bosniak I-II cyst. However, known enhancement thresholds must be adapted especially to the energy level of virtual monochromatic reconstructions. Clinical statement: DECT is a promising tool for Bosniak classification; however, known enhancement thresholds must be adapted according to the types of reconstructions used and especially to the energy level of virtual monochromatic reconstructions. Key Points: • To differentiate solid to cystic renal masses, predefined 20 HU threshold had a poor specificity using 40 keV virtual monochromatic images. • Most of Bosniak 1 masses according to MRI were also classified as Bosniak 1 on rapid kV-switching dual-energy CT (rsDECT). • Bosniak 2 hyperattenuating renal cysts mimicked solid lesion on rsDECT. [ABSTRACT FROM AUTHOR]

Objective: To determine whether a simple point‐of‐care measurement system estimating renal parenchymal volume using tools ubiquitously available could be used to replace nuclear medicine renal scintigraphy (NMRS) in current clinical practice to predict estimated glomerular filtration rate (eGFR) after nephrectomy by estimating preoperative split renal function. Patients and Methods: We performed a retrospective review of patients who underwent abdominal cross‐sectional imaging (computed tomography/magnetic resonance imaging) and mercaptoacetyltriglycine (MAG3) NMRS prior to total nephrectomy at a single institution. We developed the real‐time estimation of nephron activity with a linear measurement system (RENAL‐MS) method of estimating postoperative renal function via the following technique: renal parenchymal volume of the removed kidney relative to the remaining kidney was estimated as the product of renal length and the average of six renal parenchymal thickness measurements. The utility of this value was compared to the utility of the split renal function measured by MAG3 for prediction of eGFR and new onset Stage 3 chronic kidney disease (CKD) at ≥90 days after nephrectomy using uni‐ and multivariate linear and logistic regression. Results: A total of 57 patients met the study criteria. The median (interquartile range [IQR]) age was 69 (61–80) years. The median (IQR) pre‐ and postoperative eGFR was 74 (IQR 58–90) and 46 (35–62) mL/min/1.73 m2, respectively. [Correction added on 29 December 2023, after first online publication: The data numbers in the preceding sentence have been corrected.] Correlations between actual and predicted postoperative eGFR were similar whether the RENAL‐MS or NMRS methods were used, with correlation using RENAL‐MS being slightly numerically but not statistically superior (R = 0.82 and 0.76; P = 0.138). Receiver operating characteristic curve analysis using logistic regression estimates incorporating age, sex, and preoperative creatinine to predict postoperative Stage 3 CKD were similar between RENAL‐MS and NMRS (area under the curve 0.93 vs. 0.97). [Correction added on 29 December 2023, after first online publication: The data numbers in the preceding sentence have been corrected.] Conclusion: A point‐of‐care tool to estimate renal parenchymal volume (RENAL‐MS) performed equally as well as NMRS to predict postoperative eGFR and de novo Stage 3 CKD after nephrectomy in our population, suggesting NMRS may not be necessary in this setting. [ABSTRACT FROM AUTHOR]

Our systematic review and meta-analysis shows that 99mTc-sestamibi single-photon emission computed tomography/computed tomography has good accuracy in differentiating renal oncocytoma and hybrid oncocytic/chromophobe tumor from malignant renal tumors. However, its use should still be limited to research settings. The diagnostic accuracy of current imaging techniques in differentiating benign from malignant neoplasms in the case of indeterminate renal masses is still suboptimal. To evaluate the diagnostic accuracy of 99mTc-sestamibi (SestaMIBI) single-photon emission tomography computed tomography (SPECT)/CT in characterizing indeterminate renal masses by differentiating renal oncocytoma and hybrid oncocytic/chromophobe tumor (HOCT) from (1) all other renal lesions and (2) all malignant renal lesions. Secondary outcomes were: (1) benign versus malignant; (2) renal oncocytoma and HOCT versus clear cell (ccRCC) and papillary (pRCC) renal cell carcinoma; and (3) renal oncocytoma and HOCT versus chromophobe renal cell carcinoma (chRCC). A literature search was conducted up to November 2022 using the PubMed/MEDLINE, Embase, and Web of Science databases. Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed to identify eligible studies. Studies included were prospective and retrospective cross-sectional studies in which SestaMIBI SPECT/CT findings were compared to histology after renal mass biopsy or surgery. Overall, eight studies involving 489 patients with 501 renal masses met our inclusion criteria. The sensitivity and specificity of SestaMIBI SPECT/CT for renal oncocytoma and HOCT versus all other renal lesions were 89% (95% confidence interval [CI] 70–97%) and 89% (95% CI 86–92%), respectively. Notably, for renal oncocytoma and HOCT versus ccRCC and pRCC, SestaMIBI SPECT/CT showed specificity of 98% (95% CI 91–100%) and similar sensitivity. Owing to the relatively high risk of bias and the presence of heterogeneity among the studies included, the level of evidence is still low. SestaMIBI SPECT/CT has good sensitivity and specificity in differentiating renal oncocytoma and HOCT from all other renal lesions, and in particular from those with more aggressive oncological behavior. Although these results are promising, further studies are needed to support the use of SestaMIBI SPECT/CT outside research trials. A scan method called SestaMIBI SPECT/CT has promise for diagnosing whether kidney tumors are malignant or not. However, it should still be limited to research trials because the level of evidence from our review is low. [ABSTRACT FROM AUTHOR]

Tuberous sclerosis complex (TSC) is a genetically inherited disorder distinguished by the development of numerous benign neoplasms across multiple organ systems.Renal angiomyolipoma represents 0.3% of all primary renal tumors and are classified as benign mixed mesenchymal neoplasms. In this report, we reported the clinical presentation of a 28-year-old individual who was received by the department of urology. The patient was admitted presenting with asymptomatic, macroscopic hematuria that had been ongoing for a period of 10 days. Subsequent diagnostic evaluations revealed an association between the presenting urinary condition and tuberous sclerosis complex with a concurrent renal angiomyolipom

The extent of renal biopsy indication is being widened because of the increasing incidence of incidental renal masses; the increasing treatment options for renal cell carcinoma, including ablation therapy and novel targeted treatment; and the increasing incidence of kidney transplantation. However, percutaneous renal biopsy is technically difficult, particularly for beginners, because the skin-to-organ distance is relatively longer than those associated with other organs. In the present review, we will discuss the indications, technical considerations, efficacy, and complications of renal biopsy. Furthermore, we share practical tips of renal biopsy through many examples to help radiologists perform renal biopsy safely and effectively in various situations.

Abstract Background The purpose of this study was to compare the surgical, functional, and oncological outcomes between open partial nephrectomy (OPN) and laparoscopic partial nephrectomy (LPN). Methods This prospective, randomized study was performed on patients who underwent partial nephrectomy under general anesthesia. Patients were randomized using the closed envelope method to either LPN or OPN. Baseline demographics and surgical, functional, and oncological outcomes were compared. A per-protocol analysis was used. Results Randomized study was conducted on 166 patients. The LPN, in comparison to the OPN group, was associated with significantly shorter hospital stay (3 vs. 4 days), less blood transfusion (10% vs. 12%), longer operative time (134 min vs. 124 min), lower visual analog pain score (7 vs. 8), and lower estimated GFR (70.7 ± 17.5 vs. 72.3 ± 14.7). Conclusions Oncological and functional results were comparable between LPN and OPN. However, LPN was superior to open surgery because of less hospital stay, visual analog pain score, and blood loss.

Abstract Background Small renal mass (SRM) biopsy remains under-utilized due to stigma. Meanwhile, the alarmingly high benign findings in resected kidney masses highlight the need for improved preoperative diagnosis and patient selection. Methods The purpose of this study is to review the success rate of SRM biopsy and to evaluate its impact on patient management. A total of 168 percutaneous image-guided core needle biopsies (CNBs) of SRMs were retrieved at a tertiary academic center between 2015 and 2019. Subsequent treatment choices, side effects and outcomes were retrospectively reviewed. Results The diagnostic rate of CNB was 86.9%. Benign neoplasms accounted for a significant portion (14.3%) of SRM. Renal cell carcinomas (RCCs) were the most common diagnoses (69.6%) as expected. In biopsy-resection correlation, the positive predictive value of CNB was 100%. Tumor typing and subtyping by CNB were highly accurate, 100% and 98.3% respectively. Nuclear grading for clear cell RCC was accurate in 83.8% cases. The CNB results had significant impact on treatment. Most patients with RCCs underwent either resection (54.1%) or ablation (33.9%), in contrast to observation in benign neoplasms (90.5%). Most importantly, the benign resection rate (3.2%) in this series was much lower than the national average. Conclusion CNB provided accurate diagnoses for the majority of SRMs and revealed benign diagnoses in a subset of clinically suspicious lesions. Employment of CNB in suspicious SRM may help avoid overtreatment for benign lesions.

Background Management of small renal masses often involves a nonoperative approach, but there is a paucity of information about the use and associated predictors of such approaches. This study aimed to determine the trends in and predictors of use of nonoperative management of small renal masses. Methods Using data from the National Cancer Database for localized small renal masses (N0/M0, cT1a) diagnosed between 2010 and 2020, we conducted a cross-sectional study. Nonoperative management was defined as expectant management (active surveillance or watchful waiting) or focal ablation. Adjusted odds ratios (AORs) were calculated using multivariable logistic regression models. Results Of the 156 734 patients included, 10.5% underwent expectant management, and 13.9% underwent focal ablation. Later year of diagnosis was associated with a higher likelihood of nonoperative management. In 2020, the odds of receiving expectant management and focal ablation were 90% (AOR = 1.90, 95% confidence interval [CI] = 1.71 to 2.11) and 44% (AOR = 1.44, 95% CI = 1.31 to 1.57) higher, respectively, than in 2010. Black patients had increased odds of expectant management (AOR = 1.47, 95% CI = 1.39 to 1.55) but decreased odds of focal ablation (AOR = 0.93, 95% CI = 0.88 to 0.99). Conclusion Over the decade, the use nonoperative management of small renal masses increased, with expectant management more frequently used than focal ablation among Black patients. Possible explanations include race-based differences in physicians' risk assessments and resource allocation. Adjusting for Black race in calculations for glomerular filtration rate could influence the differential uptake of these techniques through deflated glomerular filtration rate calculations. These findings highlight the need for research and policies to ensure equitable use of less invasive treatments in small renal masses. [ABSTRACT FROM AUTHOR]

The extent of renal biopsy indication is being widened because of the increasing incidence of incidental renal masses; the increasing treatment options for renal cell carcinoma, including ablation therapy and novel targeted treatment; and the increasing incidence of kidney transplantation. However, percutaneous renal biopsy is technically difficult, particularly for beginners, because the skin-to-organ distance is relatively longer than those associated with other organs. In the present review, we will discuss the indications, technical considerations, efficacy, and complications of renal biopsy. Furthermore, we share practical tips of renal biopsy through many examples to help radiologists perform renal biopsy safely and effectively in various situations. [ABSTRACT FROM AUTHOR]

The efficacy and complication rates of percutaneous radiofrequency ablation (RFA) and cryoablation (CA) in the treatment of T1 renal masses in two Northern Italy hospitals were retrospectively investigated. Eighty-two patients with 80 T1a tumors and 10 T1b tumors treated with thermal ablation from 2015 through 2020 were included. A total of 43 tumors in 38 patients were treated with RFA (2.3 ± 0.9 cm), and 47 tumors in 44 patients were treated with CA (2.1 ± 0.8 cm). The mean follow-up observation period was 26 ± 19 months. The major complications and efficacy, as measured using the technical success and local tumor recurrence rates, were recorded. There were three (6.9%) technical failures with RFA and one (2.1%) with cryoablation (p = 0.30). Among the 40 tumors that were successfully treated with RFA, 1 tumor (2.5%) developed local tumor recurrence; 5/46 tumors that were treated with cryoablation (10.8%) developed local tumor recurrence (p = 0.17). T1b lesions (4.0 ± 0.7 cm) resulted in 1/6 technically unsuccessful cases with RFA and 0/4 with CA. No recurrent disease was detected in the T1b lesions. Major complications occurred after 2.3% (1/43) of RFAs and 0/47 of cryoablation procedures. RFA and cryoablation are both effective in the treatment of renal masses. Major complications with either procedure are uncommon. [ABSTRACT FROM AUTHOR]

Robot-assisted partial nephrectomy (RAPN) is increasingly being used for the complex surgical management of renal masses. The comparison of RAPN with open partial nephrectomy (OPN) has not yet led to a unified conclusion with regard to perioperative outcomes. To conduct a systematic review and meta-analysis of the literature on the perioperative outcomes of RAPN compared with OPN. We performed a systematic search in PubMed, Embase, Web of Science, and Cochrane Library database for randomized control trials (RCTs) and non-RCTs that compare OPN to RAPN. The primary outcomes included perioperative, functional and oncologic. The odds ratio (OR) and weighted mean difference (WMD) were applied for the comparison of dichotomous and continuous variables with 95% confidence intervals (CIs). Five studies, comprising 936 patients, were included in the meta-analysis. Our findings indicated that there were no significant differences in blood loss, minor complication rate, eGFR decline from baseline, positive surgical margin, and ischemia time between OPN and RAPN. However, RAPN was associated with a shorter hospital stay (WMD 1.64 days, 95% CI − 1.17 to 2.11; p < 0.00001), lower overall complication rate (OR 1.72, 95% CI 1.21–2.45; p < 0.002), lower transfusion rate (OR 2.64, 95% CI 1.39–5.02; p = 0.003) and lower major complication rate (OR 1.76, 95% CI 1.11–2.79; p < 0.02) compared to OPN. Additionally, the operation time for OPN was shorter than that for RAPN (WMD − 10.77 min, 95% CI − 18.49 to − 3.05, p = 0.006). In comparison with OPN, RAPN exhibits better results in terms of hospital stay, overall complications, blood transfusion rate, and major complications, with no significant difference in intraoperative blood loss, minor complications, PSM, ischemia time, and short-term postoperative eGFR decline. However, the operation time of OPN is slightly shorter than that of RAPN. [ABSTRACT FROM AUTHOR]

Mixed epithelial and stromal tumor of the kidney (MESTK) is a rare benign kidney tumor. In rare cases, malignant transformation, such as sarcomatoid features indicates poor clinical outcomes.In this study, we will describe a 45 years old man with a diagnosis of MESTK with malignant transformation of the sarcomatoid component, after right radical nephrectomy. The patient underwent chemotherapy with adriamycin, ifosfamide, and granulocyte-colony stimulating factor (G-CSF).The radiological characteristics of MESTK can pose diagnostic challenges due to its non-unique radiological appearance. The presence of sarcomatoid transformation is a hallmark feature of malignant MESTK which can be very aggressive.

Matthew Chau,&ast; Ivan Thia,&ast; Manmeet Saluja Royal Perth Hospital, Perth, Western Australia, Australia&ast;These authors contributed equally to this workCorrespondence: Matthew Chau, Department of Urology, Level 11. Royal Perth Hospital, Victoria Square, Perth, Western Australia, 6000, Australia, Tel +61 8 9224 2244, Email matthew.chau@health.wa.gov.auObjectives: The role of needle core renal biopsy in large renal masses, defined as lesions larger than 4 cm, is debatable, as larger renal masses are associated with malignant histology. We aim to review the safety and impact of renal biopsy on the management of large renal masses.Methods: A retrospective, single-center review of all renal biopsies performed between January 2011 and December 2020 at Royal Perth Hospital was conducted. Indications for biopsy, complications and final management plans were correlated to assess the value of biopsies in large renal masses.Results: In total, 126 biopsies were performed. Indeterminate imaging findings and comorbidities were the main indications for biopsies. We identified 116 (92.1%) diagnostic biopsies and 10 (8.0%) non-diagnostic biopsies due to insufficient samples or inflammatory tissue. Of the diagnostic biopsies, 99 (78.6%) were malignant and 17 (13.5%) were benign. Unnecessary extirpative surgery was avoided in 17 patients. Histology included renal cell carcinoma (96%) and other malignancies such as urothelial carcinoma (3%) and non-Hodgkin’s lymphoma (1%). Benign biopsies identified histology including angiomyolipoma (35.3%) and oncocytoma (52.5%). The median follow-up time was 68 months (range 19– 132 months).Conclusion: Renal biopsies in large renal masses may aid in preventing unnecessary surgery, especially in situations where imaging findings are equivocal or in patients with many comorbidities.Keywords: biopsy, kidney neoplasms, nephrectomy, renal mass

This article summarizes a study conducted by the Michigan Urological Surgery Improvement Collaborative (MUSIC) on the rates of positive surgical margins (PSM) following partial nephrectomy (PN) for kidney tumors. The study found that high-volume centers had lower rates of PSM, indicating that centralization of care may be beneficial. The study also highlighted the importance of using ultrasound during the planning and resection of endophytic tumors and referring challenging cases to higher volume surgeons. The authors hope that this report will encourage urological surgeons to improve their surgical approach and achieve better PSM rates. The study was funded in part by Blue Cross Blue Shield of Michigan and the authors have no conflicts of interest. [Extracted from the article]

Background: There is a lack of evidence on acute kidney injury (AKI) and new-onset chronic kidney disease (CKD) after surgery for localised renal masses (LRMs) in patients with two kidneys and preserved baseline renal function. Objective: To evaluate the prevalence and risk of AKI and new-onset clinically significant CKD (csCKD) in patients with a single renal mass and preserved renal function after being treated with partial (PN) or radical (RN) nephrectomy. Design, setting, and participants: We queried our prospectively maintained databases to identify patients with a preoperative estimated glomerular filtration rate (eGFR) of ≥60 ml/min/1.73 m2 and a normal contralateral kidney who underwent PN or RN for a single LRM (cT1-T2N0M0) between January 2015 and December 2021 at four high-volume academic institutions. Intervention: PN or RN. Outcome measurements and statistical analysis: The outcomes of this study were AKI at hospital discharge and the risk of new-onset csCKD, defined as eGFR

Introduction: Active surveillance has become a standard of care for the management of small renal masses. Decision to transition from surveillance to intervention relies on several factors including growth kinetics, histologic grade on biopsy and patient comorbidities. Management of renal masses in pregnancy presents a unique change when clinical triggers must be weighed with risk to fetus. We present the case of a third trimester patient with an enlarging and enhancing renal mass managed with robotic assisted laparoscopic partial nephrectomy. Histologic analysis was consistent with renal leiomyoma. Renal leiomyomas are a rare benign mesenchymal tumor influenced by changes in progesterone-estrogen axis.

OBJECTIVES: Infl ammatory markers indicate immune system responses. BACKGROUND: We retrospectively explored whether the platelet/lymphocyte ratio (PLR), neutrophil/ lymphocyte ratio (NLR), and red blood cell distribution width (RDW) were predictive of malignant disease. MATERIAL AND METHODS: Between 2019 and 2023, 148 patients diagnosed with malignant and benign renal tumors via imaging or biopsy were included. Of these tumors, 117 were malignant and 31 were benign. Blood samples were taken for calculation of the NLR, PLR, and RDW prior to renal biopsy or operation. RESULTS: The NLR, PLR, and RDW did not differ signifi cantly between patients with malignant and benign renal masses (all p > 0.05). The PLR signifi cantly increased with the T stage of malignant masses (p = 0.011). According to the T stage, the RDW cutoff was 45.7, the sensitivity was 40 %, and the specifi city 82.4 %; the respective values for PLR were 134.9, 70 %, and 70.5 % (p = 0.026 and p = 0.003, respectively). CONCLUSION: The NLR, PLR, and RDW were not predictive in this study because we only included early- stage patients lacking lymph node involvement and the follow-up was short. In patients with renal cell carcinomas, the RDW and PLR increase with the tumor burden and predict poor prognosis (Tab. 5, Fig. 1, Ref. 23). Text i n PDF www.elis.sk. [ABSTRACT FROM AUTHOR]

Introduction: T3a renal masses include a diverse group of tumors that invade the perirenal and/or sinus fat, pelvicaliceal system, or renal vein. The majority of cT3a renal masses represent renal cell carcinoma (RCC) and have historically been treated with radical nephrectomy (RN) given their aggressive nature. With the adoption of minimally invasive approaches to renal surgery, the combination of improved observation, pneumoperitoneum, and robotic articulation has allowed urologists to consider partial nephrectomy (PN) for more complex tumors. Herein, we review the existing literature regarding robot-assisted PN (RAPN) and robot-assisted RN (RARN) in the management of T3a renal masses. Methods: A literature search was performed using PubMed for articles evaluating the role of RARN and RAPN for T3a renal masses. Search parameters were limited to English language studies. Applicable studies were abstracted and included in this narrative review. Results: T3a RCC caused by renal sinus fat or venous involvement is associated with ∼50% lower cancer-specific survival than those with perinephric fat invasion alone. CT and MRI can both be used to stage cT3a tumors, however, MRI is more accurate when assessing venous involvement. Upstaging to pT3a RCC during RAPN does not confer a worse prognosis than pT3a tumors treated with RARN; however, patients who undergo RAPN for T3a RCC with venous involvement have relatively higher rates of recurrence and metastasis. Intraoperative tools including drop-in ultrasound, near-infrared fluorescence, and 3D virtual models improve the ability to perform RAPN for T3a tumors. In well-selected cases, warm ischemia times remain reasonable. Conclusions: cT3a renal masses represent a diverse group of tumors. Depending on substratification of cT3a, RARN or RAPN can be employed for treatment of such masses. [ABSTRACT FROM AUTHOR]

The incidence of renal mass detection has increased during recent decades, with an increased diagnosis of small renal masses, and a final benign diagnosis in some cases. To avoid unnecessary surgeries, there is an increasing interest in using radiomics tools to predict histological results, using radiological features. We performed a narrative review to evaluate the use of radiomics in renal mass characterization. Conventional images, such as computed tomography (CT) and magnetic resonance (MR), are the most common diagnostic tools in renal mass characterization. Distinguishing between benign and malignant tumors in small renal masses can be challenging using conventional methods. To improve subjective evaluation, the interest in using radiomics to obtain quantitative parameters from medical images has increased. Several studies have assessed this novel tool for renal mass characterization, comparing its ability to distinguish benign to malign tumors, the results in differentiating renal cell carcinoma subtypes, or the correlation with prognostic features, with other methods. In several studies, radiomic tools have shown a good accuracy in characterizing renal mass lesions. However, due to the heterogeneity in the radiomic model building, prospective and external validated studies are needed. [ABSTRACT FROM AUTHOR]

The frequency of detection of renal masses has increased over recent decades, causing a concurrent increase in early intervention by surgery. Growing recognition that this approach was contributing to overtreatment led to the broader use of preoperative renal mass biopsy (RMB) by core biopsy and/or fine‐needle aspiration. Because more options for management, such as active surveillance and personalized therapy, are becoming increasingly available, a diagnosis by RMB is becoming a valuable tool for risk stratification and clinical decision making. Guidelines from various professional organizations have outlined situations in which RMB should be used, and it has been shown to be safe and effective. Rapid on‐site evaluation (ROSE) using touch preparations of core biopsy or fine‐needle aspiration smears provides an immediate assessment of adequacy and appropriate triage. ROSE also ensures sufficient material to perform immunohistochemistry and molecular studies for more accurate characterization of renal masses and personalized treatment. The integral role of cytopathology laboratories in precision medicine can also be successfully used in optimizing the workup of RMB from ROSE to final diagnosis, prognostication, and personalized management of kidney tumors. Herein, the authors review their extensive experience working together with interventional radiology and urology colleagues to use core biopsy and ROSE at the time of RMB for diagnosis and management of these lesions. There is greater recognition for the role of renal mass biopsy (RMB) in guiding patient management and, although practices vary between institutions, the overall use of RMB is increasing in the current era of precision management. Cytopathology laboratories play an important role in optimizing the workup of RMB from rapid on‐site evaluation to final diagnosis. Herein, the authors review the existing literature and share their experience from a large, academic tertiary care center. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of the study is to assess the value of RENAL nephrometry score (RNS) in predicting surgical decisions, complications, and decreases in kidney function in patients with localized renal tumors. Methods: Cases with solitary, solid, and enhancing renal masses were included, scheduled for nephron-sparing surgery (NSS), and assessed using routine laboratory and radiological data necessary for calculating the RENAL score. The primary endpoint was conversion to radical nephrectomy (RN), while the secondary endpoint was the prediction of a drop in renal function assessed by postoperative estimated glomerular filtration rate (eGFR) at the last follow-up visit compared with the preoperative values. The association between the scoring system and perioperative outcomes was evaluated. Results: In all, 84 cases were included, NSS was accomplished in 67 cases while conversion to RN was mandatory in 17 patients, median (interquartile range) RENAL score was 6.2 (4–10) for NSS and 9.7 (6–12) for RN (P < 0.001). Higher grades of complications were observed in the high-complexity subgroup. eGFR was 79.8 that dropped to 75.6 ml/min/1.73 m2 in the late value in patients who underwent NSS, while it was 82.9 that dropped to 58.3 ml/min/1.73 m2 in the late value in patients who converted into RN (P < 0.001). The percentage of drop in eGFR was significantly higher in the moderate and high-risk groups, which was positively correlated with the warm ischemia time. Regression analysis revealed that the continuous RENAL score was a more significant predictor of conversion to RN than tumor size alone. In the 67 NNS cases, the percentage decrease in eGFR was predicted using the continuous RENAL score. Conclusion: The RNS is a significant predictor of conversion to RN and can predict the percentage decrease in eGFR after NSS. Further investigations and follow-ups are necessary. [ABSTRACT FROM AUTHOR]

Small renal masses (SRM) are defined as contrast-enhancing solid masses detected on diagnostic imaging, with a size of less than or equal to 4cm, corresponding to renal cell carcinoma stage T1a. These tumours are mainly benign, with an indolent nature and rare metastatic potential. Given the size and nature of these tumours, there has been a significant evolution and in management modalities of these tumours. These range from conventional radical approaches such as radical nephrectomy, partial nephrectomy, to more conservative approaches such as active surveillance, and some novel emerging management strategies such as various thermal ablation techniques. The treatment decision depends on patient factors such as age and co-morbidity, and tumour factor on radiological imaging, such as tumour size, location, growth rate and biopsy result. In this review, we aim to provide the latest updates on approaching SRM and various management modalities. [ABSTRACT FROM AUTHOR]

PurposeThere is substantial variation in the radiologic terms used to characterize renal masses, leading to ambiguity and inconsistency in clinical radiology reports and research studies. The purpose of this study was to develop a standardized lexicon to describe renal masses at CT and MRI.Materials and methodsThis multi-institutional, prospective, quality improvement project was exempt from IRB oversight. Thirteen radiologists belonging to the Society of Abdominal Radiology (SAR) disease-focused panel on renal cell carcinoma representing nine academic institutions participated in a modified Delphi process to create a lexicon of terms used to describe imaging features of renal masses at CT and MRI. In the first round, members voted on terms to be included and proposed definitions; subsequent voting rounds and a teleconference established consensus. One non-voting member developed the questionnaire and consolidated responses. Consensus was defined as ≥ 80% agreement.ResultsOf 37 proposed terms, 6 had consensus to be excluded. Consensus for inclusion was reached for 30 of 31 terms (13/14 basic imaging terms, 8/8 CT terms, 6/6 MRI terms and 3/3 miscellaneous terms). Despite substantial initial disagreement about definitions of 'renal mass,' 'necrosis,' 'fat,' and 'restricted diffusion' in the first round, consensus for all was eventually reached. Disagreement remained for the definition of 'solid mass.'ConclusionsA modified Delphi method produced a lexicon of preferred terms and definitions to be used in the description of renal masses at CT and MRI. This lexicon should improve clarity and consistency of radiology reports and research related to renal masses.

It is extremely rare for granulomatosis with polyangiitis to form masses in the kidneys. Magnetic resonance imaging findings of renal masses caused by this disease have been infrequently reported. In this study, we report a case of renal masses caused by granulomatosis with polyangiitis with different findings. While on steroid treatment for a recently diagnosed granulomatosis with polyangiitis, a man in his 60s underwent computed tomography for a hepatic dysfunction. Computed tomography showed incidental findings of a 40 mm × 35 mm mass in the left kidney and two 8 mm × 8 mm masses in the right kidney; all masses were hypovascular. On magnetic resonance imaging, the left renal mass showed a hyperintense signal with slightly hypointense signal rim on T2-weighted imaging. The left renal mass showed a strong hypointense signal where the mass abutted the renal capsule. On diffusion-weighted imaging, the left renal mass showed an isointense signal with a hyperintense signal rim. Both right renal masses showed an isointense signal with slightly hypointense signal rim on T2-weighted imaging and hyperintense signal on diffusion-weighted imaging. Suspecting renal masses caused by the disease, the patient was then treated with steroids and methotrexate. After 6 months of treatment, both right renal masses resolved; however, the left renal mass shrank but abnormal signal remained. Based on the treatment course, it is conceivable that the renal masses were caused by granulomatosis with polyangiitis.

Small renal masses (SRM) are defined as contrast-enhancing solid masses detected on diagnostic imaging, with a size of less than or equal to 4cm, corresponding to renal cell carcinoma stage T1a. These tumours are mainly benign, with an indolent nature and rare metastatic potential. Given the size and nature of these tumours, there has been a significant evolution and in management modalities of these tumours. These range from conventional radical approaches such as radical nephrectomy, partial nephrectomy, to more conservative approaches such as active surveillance, and some novel emerging management strategies such as various thermal ablation techniques. The treatment decision depends on patient factors such as age and co-morbidity, and tumour factor on radiological imaging, such as tumour size, location, growth rate and biopsy result. In this review, we aim to provide the latest updates on approaching SRM and various management modalities.

Purpose: The purpose of the study is to assess the value of RENAL nephrometry score (RNS) in predicting surgical decisions, complications, and decreases in kidney function in patients with localized renal tumors. Methods: Cases with solitary, solid, and enhancing renal masses were included, scheduled for nephron-sparing surgery (NSS), and assessed using routine laboratory and radiological data necessary for calculating the RENAL score. The primary endpoint was conversion to radical nephrectomy (RN), while the secondary endpoint was the prediction of a drop in renal function assessed by postoperative estimated glomerular filtration rate (eGFR) at the last follow-up visit compared with the preoperative values. The association between the scoring system and perioperative outcomes was evaluated. Results: In all, 84 cases were included, NSS was accomplished in 67 cases while conversion to RN was mandatory in 17 patients, median (interquartile range) RENAL score was 6.2 (4–10) for NSS and 9.7 (6–12) for RN (P < 0.001). Higher grades of complications were observed in the high-complexity subgroup. eGFR was 79.8 that dropped to 75.6 ml/min/1.73 m2 in the late value in patients who underwent NSS, while it was 82.9 that dropped to 58.3 ml/min/1.73 m2 in the late value in patients who converted into RN (P < 0.001). The percentage of drop in eGFR was significantly higher in the moderate and high-risk groups, which was positively correlated with the warm ischemia time. Regression analysis revealed that the continuous RENAL score was a more significant predictor of conversion to RN than tumor size alone. In the 67 NNS cases, the percentage decrease in eGFR was predicted using the continuous RENAL score. Conclusion: The RNS is a significant predictor of conversion to RN and can predict the percentage decrease in eGFR after NSS. Further investigations and follow-ups are necessary.

Abstract Background Ewing’s sarcoma is categorized as small round cell aggressive tumor which commonly occurs in bone and soft tissue. Primary renal Ewing’s sarcoma is an extremely rare entity and accounts for less than 1% of renal masses. It is characterized by a very aggressive course, with very few reported cases in the literature. Primary renal Ewing’s sarcoma is indistinguishable from renal cell carcinoma on anatomical imaging and therefore need histopathological correlation for confirmation. The positron emission tomography (PET) fused with computed tomography (CT) helps in the evaluation of disease, for staging and metastatic workup. Case presentation We present a case of 48-year-old lady who presented to urology department with difficulty in passing urine for 5 months associated with pain in the right flank region. She had an episode of haematuria 5 months back. Contrast enhanced CT showed a large lobulated heterogeneously enhancing right retroperitoneal mass in renal fossa. Histopathological examination and immunohistochemistry were suggestive of Ewing’s sarcoma. The PET/CT revealed FDG avid right renal mass with lymph nodal and skeletal metastasis. Conclusions Ewing’s sarcoma being aggressive tumour usually present with bone, liver and lung metastasis along with lymph nodal metastasis at time of diagnosis. The 18 F FDG PET/CT helps in diagnosis, staging, appropriate treatment planning, restaging, response evaluation and prognostication of Ewing’s sarcoma.

Purpose: To automatically evaluate renal masses in CT images by using a cascade 3D U-Net- and ResNet-based method to accurately segment and classify focal renal lesions. Material and Methods: We used an institutional dataset comprising 610 CT image series from 490 patients from August 2009 to August 2021 to train and evaluate the proposed method. We first determined the boundaries of the kidneys on the CT images utilizing a 3D U-Net-based method to be used as a region of interest to search for renal mass. An ensemble learning model based on 3D U-Net was then used to detect and segment the masses, followed by a ResNet algorithm for classification. Our algorithm was evaluated with an external validation dataset and kidney tumor segmentation (KiTS21) challenge dataset. Results: The algorithm achieved a Dice similarity coefficient (DSC) of 0.99 for bilateral kidney boundary segmentation in the test set. The average DSC for renal mass delineation using the 3D U-Net was 0.75 and 0.83. Our method detected renal masses with recalls of 84.54% and 75.90%. The classification accuracy in the test set was 86.05% for masses (<5 mm) and 91.97% for masses (≥5 mm). Conclusion: We developed a deep learning-based method for fully automated segmentation and classification of renal masses in CT images. Testing of this algorithm showed that it has the capability of accurately localizing and classifying renal masses. [ABSTRACT FROM AUTHOR]

Purpose: To determine the natural history and necessity of long‐term follow‐up of renal masses that do not demonstrate enhancement on contrast‐enhanced ultrasound (CEUS). Methods: This retrospective single‐center study was approved by our local IRB and is HIPAA compliant. Exactly 405 patients with 620 non‐enhancing renal masses on CEUS from a previously reported study were followed for up to 10 years. Techniques and equipment are described in the original manuscript. Patient charts and imaging studies were reviewed for the change in features. There were 117 (18.6%) patients lost to follow‐up leading to 341 patients with 512 lesions. The lesion size, patient age, number of lesions per patient, and Bosniak class assigned at the initial examination was recorded. Results: Mean patient age was 66 ± 12.6 years (range 17–95 years). Average time of follow‐up was 58.9 ± 41.7 months (range 1–207 months). There was a mean of 1.5 ± 1.0 lesions per patient (range 1–7 lesions). Lesion size was 24.9 ± 18.2 mm (range 3–161 mm). There were 276 (53.9%) patients with >5‐year follow‐up and 78 (15.2%) patients with >10‐year follow‐up. The probability of change within 5 years was 0% (95% CI: 0–0.37 per 100PY) and 10 years 0% (95% CI: 0.0–0.18 per 100PY). Two lesions (0.4%) resolved by 60 months. Five lesions (1.0%) decreased in size. Four lesions (0.8%) increased in size >20% during the follow‐up period but remained benign on subsequent imaging. Conclusion: Any non‐enhancing renal mass on CEUS can be classified as benign. Access the CME test here and search by article title. [ABSTRACT FROM AUTHOR]

OBJECTIVE. The purpose of this study was to evaluate the efficacy of radiofrequency ablation (RFA) of renal masses comparing a group who did not undergo intraprocedural CT and a group who did. MATERIALS AND METHODS. A retrospective review included 45 consecutively registered patients who underwent RFA of renal masses. If an adequate biopsy specimen was not obtained or follow-up was inadequate, the patient was eliminated from review from calculation of primary technical efficacy. The inclusion criterion was having undergone RFA with two cooled-tip electrodes. Baseline demographics (age, body mass index, and sex), renal mass characteristics (diameter, side, location, position, morphologic features, type of mass, and grade), technical details (repositioning and hydrodissection), and complications were evaluated. Follow-up images were evaluated to determine the presence of recurrence at the ablation site in the two groups. RESULTS. Among the 45 patients who underwent RFA, 13 did not undergo intraprocedural CT and 32 intraprocedural did. Thirty-five patients met the criteria for follow-up and positive biopsy results. For calculation of recurrence, 10 patients were in the group who did not and 25 were in group who did undergo intraprocedural contrast-enhanced CT. No correlation was found between baseline demographics, renal mass characteristics, and technical results of the two groups. There was an 89% overall technical efficacy rate with a 96% primary technical efficacy rate in the group who underwent intraprocedural CT compared with a 70% rate in the group who did not undergo intraprocedural CT. Negative correlation was found between the groups with respect to technical efficacy rate at p < 0.05. CONCLUSION. Intraprocedural contrast-enhanced CT yields important information about completeness of ablation during the procedure, allowing probe repositioning and thus better therapeutic effect.

Renal cryoablation (CA) has become an accepted treatment option for patients with small renal tumors and co-morbidities that make them less favorable for surgical intervention. Complications from renal CA have been previously reported and are generally associated with increasing size and central location of the tumor. Ureteral injury from renal CA, although rare, can be difficult to manage and may require complex surgeries in patients who are poor surgical candidates to begin with. We report a case of a renal mass CA complicated by proximal ureteral necrosis and transection, treated with multiple minimally invasive procedures ultimately resulting in successful bridging of the necrotic segment with nephroureteral stent and thus avoiding major surgery.

Purpose: To describe clinical features of patients with oncocytoma on renal biopsy (RMB), correlation with final histology on surgically treated patients, and predictive factors of discrepancy between RMB and final histology. Methods: This was a retrospective study conducted in the framework of the UroCCR project (NCT03293563). All tumors with oncocytoma on RMB were selected and all pathological reports were reviewed. Patients with the RMB simultaneously performed with a focal treatment, synchronous bilateral tumors and ambiguous RMB report were excluded. Discrepancy between RMB and definitive histology was evaluated using a uni- and multivariable logistic regression analyses model. Results: Overall, 119 tumors with oncocytoma on RMB, from 15 centers, were included. Of those, 54 (45.4%) had upfront surgery and 65 (54.6%) had active surveillance (AS). In renal masses with initial active surveillance, with a median follow-up of 28 months, 23 (19.3%) underwent surgery, 4 (3.4%) received focal treatment and 38 (31.9%) remained on AS. On final pathology, only 51 of the 75 surgically treated tumors (68.0%) had oncocytoma, while 24 presented malignant tumors (mainly chromophobe carcinoma (19.2%), and hybrid oncocytic/chromophobe tumor (HOCT) (6.8%)) leading to a discrepancy of 32.0% between RMB and final pathology. The only predictive factor of a discrepancy between RMB and definitive histology was a biopsy done outside of the center (Odds ratio: 3.22 [95%-confidence interval: 1.08–9.61], p = 0.03). Conclusion: Despite the increase of RMB in more and more centers, histologic discrepancy between RMB and definitive histology remains significant. This information should be discussed with patients and taken into consideration before treatment decision. [ABSTRACT FROM AUTHOR]

Renal cell carcinoma (RCC) in solitary kidney (SK) represents a challenging scenario. We sought to compare outcomes of robot-assisted partial nephrectomy (RAPN) versus percutaneous thermal ablation (PTA) in SK patients with renal tumors cT1. We performed a multicenter retrospective analysis of SK patients treated for RCC. The PTA group included cryoablation or radiofrequency ablation. We collected baseline characteristics, intraoperative, pathological, and post-operative data. We applied an arbitrary composite "trifecta" to assess surgical, functional, and oncological outcomes, only for malignant histology. RFS analysis was performed using the Kaplan-Meier method. Multivariable regression analysis was performed to determine independent predictors of "trifecta" achievement. We included 198 SK patients (RAPN, n = 50; PTA n = 119). Mean clinical tumor size was not significantly different while R.E.N.A.L. score was higher for RAPN (p < 0.001). No differences in intra and major post-procedural complications. Recurrence rate was higher in PTA group but not statistically significant (p < 0.328). No difference in metastasis rate was found (p = 0.435). RFS was 96.1% in RAPN and 86.8% in PTA cohort (p = 0.003) while no difference in PFS was detected (p = 0.1). Trifecta was achieved in 72.5% of RAPN vs 77.3% of PTA (p = 0.481). Multivariable analysis has not detected predictors for Trifecta achievement. PTA offers good outcomes in the management of SK patients with RCC. Compared with RAPN, it might carry a higher risk of recurrence; on the other hand, re-treatment is possible. Overall, PTA can be safely offered to treat SK patients presenting RCC. In general, it should be preferred in more frail patients to minimize the risk of complications. [ABSTRACT FROM AUTHOR]