Solid Renal Tumors Research Articles

Clinicopathological Features, Management and Outcome of Paediatric Solid Renal Tumours in Southeast Nigeria: The Need for Protocol and Multidisciplinary Collaboration

Introduction: Renal malignancies are common in children and they constitute 6-7% of all childhood tumours and nephroblastoma is the most common solid renal tumour in children. Currently, standardised institutional protocols in management of renal tumours in children are the norm. Large scale collaborative studies have started emerging, yet not much has been documented on the clinical presentation, pathology and outcome of solid renal tumours particularly in Africa. Aim: To review the presentations, pathology and the management-outcome of solid renal tumour in the centre in the absence of a coordinated protocol and multi-disciplinary collaboration. Materials and Methods: This was a nine and a half year longitudinal retrospective audit study of consecutive patients with solid renal tumours managed in a single tertiary centre: Nnamdi Azikiwe University Teaching Hospital Nnewi South-east Nigeria. It took place from January 2009-June 2018. Relevant data on demography, clinical features, management and outcome were extracted from records. Results were analysed using Statistical Package for Social Sciences (SPSS) version 22. Categorical data were tested for independence using Chi-square test and significant p-value set at <0.05. Results: Twenty two paediatric cases (15 males and 7 females) were included in the study. The mean age at presentation was 50.10±4.8 months. There were 15 males and 7 females. The mean duration of symptoms was 5.5 months; 21 (95%) presented with abdominal masses while 6 (27.3%) had gross haematuria and 13 (59%) were emaciated. Tumours involved left kidney in 15 (68%). Histological reports were available in 9 cases with nephroblastoma being the most common 6 (27.3%). The Commonest stage was stage 3, 10 (45%) and commonest procedure was nephroureterectomy, 11 (50%). Neo-adjuvant and adjuvant therapies were inconsistent. Conclusion: Late presentation, discordant treatment protocol, noncompletion of treatment and poor collaboration, were found to contribute largely to poor outcome of solid renal tumours in children in our setting. It is strongly believed that adoption of standard protocol and a multidisciplinary collaboration in management will improve records keeping and outcome.

In Situ Metabolomics Expands the Spectrum of Renal Tumours Positive on 99mTc-sestamibi Single Photon Emission Computed Tomography/Computed Tomography Examination

BackgroundDefinite noninvasive characterisation of renal tumours positive on 99mTc-sestamibi single photon emission computed tomography/computed tomography (SPECT/CT) examination including renal oncocytomas (ROs), hybrid oncocytic chromophobe tumours (HOCTs), and chromophobe renal cell carcinoma (chRCC) is currently not feasible. ObjectiveTo investigate whether combined 99mTc-sestamibi SPECT/CT and in situ metabolomic profiling can accurately characterise renal tumours exhibiting 99mTc-sestamibi uptake. Design, setting, and participantsA tissue microarray analysis of 33 tumour samples from 28 patients was used to investigate whether their in situ metabolomic status correlates with their features on 99mTc-sestamibi SPECT/CT examination. In order to validate emerging data, an independent cohort comprising 117 tumours was subjected to matrix-assisted laser desorption/ionisation mass spectrometry imaging (MALDI MSI). Outcome measurements and statistical analysisMALDI MSI data analysis and image generation were facilitated by FlexImaging v. 4.2, while k-means analysis by SCiLS Lab software followed by R-package CARRoT analysis was used for assessing the highest predictive power in the differential of RO versus chRCC. Heatmap-based clustering, sparse partial least-squares discriminant analysis, and volcano plots were created with MetaboAnalyst 3.0. Results and limitationsWe identified a discriminatory metabolomic signature for 99mTc-sestamibi SPECT/CT–positive Birt-Hogg-Dubè–associated HOCTs versus other renal oncocytic tumours. Metabolomic differences were also evident between 99mTc-sestamibi–positive and 99mTc-sestamibi–negative chRCCs, prompting additional expert review; two of three 99mTc-sestamibi–positive chRCCs were reclassified as low-grade oncocytic tumours (LOTs). Differences were identified between distal-derived tumours from those of proximal tubule origin, including differences between ROs and chRCCs. ConclusionsThe current study expands the spectrum of 99mTc-sestamibi SPECT/CT–positive renal tumours, encompassing ROs, HOCTs, LOTs, and chRCCs, and supports the feasibility of in situ metabolomic profiling in the diagnostics and classification of renal tumours. Patient summaryFor preoperative evaluation of solid renal tumours, 99mTc-sestamibi single photon emission computed tomography/computed tomography (SPECT/CT) is a novel examination method. To increase diagnostic accuracy, we propose that 99mTc-sestamibi–positive renal tumours should be biopsied and followed by a combined histometabolomic analysis.

Spontaneous clinical tumor lysis syndrome in solid renal tumor: first case report in non-metastatic renal carcinoma

Spontaneous tumor lysis syndrome is a rare emergency in onco-nephrology that results from extensive cancer cell lysis independent of antitumoral therapy. It is common among hematological tumors and can be rarely seen with solid tumors. In medical literature, there is only one case report with spontaneous tumor lysis syndrome in renal cell carcinoma and it was associated with metastases. To the best of our knowledge, this is the first report of spontaneous tumor lysis syndrome in non-metastatic renal cell carcinoma.

Dual-Phase 99mTc-MIBI SPECT/CT in the Characterization of Enhancing Solid Renal Tumors: A Single-Institution Study of 147 Cases.

The aim of this study was to investigate the value of dual-phase Tc-MIBI SPECT/CT in the differential diagnosis between benign and malignant enhancing solid renal tumors. Totally, 180 patients were imaged with dual-phase Tc-MIBI SPECT/CT, which was performed 30 minutes and 90 minutes after Tc-MIBI administration. Among them, 147 patients with 148 histologically proved solid renal tumors met the selection criteria and were included for the final analysis. Relative quantification was performed by measuring the radioactive uptake ratio of tumor to the normal renal parenchymal background for both early and delayed images. Benign renal tumors (4 renal oncocytomas and 8 lipid-poor angiomyolipomas) demonstrated a significantly higher early relative uptake value (ERUV) and delayed relative uptake value (DRUV) than malignant renal tumors (n = 136; both P < 0.0001). The ERUV cutoff value of 0.53 helped to differentiate benign from malignant renal tumors, with sensitivity of 100%, specificity of 94.8%, and accuracy of 95.3% for the diagnosis of benign renal tumors. The DRUV cutoff value of 0.50 helped to differentiate benign from malignant renal tumors, with sensitivity of 100%, specificity of 96.3%, and accuracy of 96.6% for the diagnosis of benign renal tumors. There was no statistically significant difference between the efficacy of ERUV and DRUV in the differential diagnosis between benign and malignant renal tumors (P = 0.5). The efficacies of ERUV and DRUV were all significantly higher than the retention index (both P < 0.0001). Both early and delayed phase Tc-MIBI SPECT/CT are helpful for distinguishing benign renal oncocytoma and lipid-poor angiomyolipoma from malignant renal tumors, and the delayed phase imaging tends to show higher diagnostic accuracy.

Predicting common solid renal tumors using machine learning models of classification of radiologist-assessed magnetic resonance characteristics.

Solid renal masses (SRM) are difficult to differentiate based on standard MR features. The purpose of this study was to assess MR imaging features of SRM to evaluate performance of ensemble methods of classifying SRM subtypes. MR images of SRM (n = 330) were retrospectively evaluated for standard and multiparametric (mp) features. Models of MR features for predicting malignant and benign lesions as well as subtyping SRM were developed using a training dataset and performance was evaluated in a test data-set using recursive partitioning (RP), gradient booting machine (GBM), and random forest (RF) methods. In the test dataset, GBM and RF models demonstrated an accuracy of 86% (95% CI 75% to 93%) for predicting benign versus malignant SRM compared to 83% (95% CI 71% to 91%) for the RP model. RF had the greatest accuracy in predicting SRM subtypes, 81.2% (95% CI 69.5% to 89.9%) compared with GBM 73.4% (95% CI 60.9% to 83.7%) or RP 70.3% (95% CI 57.6% to 81.1%). Marginal homogeneity was reduced by the RF model compared with the RP model (P < 0.001), but not the GBM model (P = 0.135). All models had high sensitivity and specificity for clear cell and papillary renal cell carcinomas (RCC), but performed less well in differentiating chromophobe RCC, oncocytomas, and fat-poor angiomyolipomas. Ensemble methods for prediction of SRM from radiologist-assessed image characteristics have high accuracy for distinguishing benign and malignant lesions. SRM subtype classification is limited by the ability to categorize chromophobe RCCs, oncocytomas, and fat-poor angiomyolipomas.

Renal Angiomyolipoma: What the Radiologist Needs to Know

Renal angiomyolipoma (AML) is the most common benign solid renal neoplasm seen in daily clinical practice, with an estimated prevalence of 0.2% to 0.6%.1 It is a triphasic mesenchymal neoplasm composed of varying amounts of dysmorphic vasculature, smooth muscle, and mature adipocytes. Pathologically, AML is now considered among the family of perivascular epithelioid cell tumors. Approximately 80% of cases are sporadic, with mean age at presentation being 43 years and most cases identified at fourth to sixth decades of life. There is also a strong female predilection, with female-to-male ratio of 4:1 in sporadic cases.1 Twenty percent of cases are associated with tuberous sclerosis (TS). Of note, AMLs may also be found in patients with lymphangioleiomyomatosis. AMLs are often found incidentally in imaging done for other purposes, but if symptomatic, they present most frequently with retroperitoneal hemorrhage, which can be fatal. The shock due to severe hemorrhage from rupture has been described in the literature as Wunderlich syndrome. Patients may present with multiple other symptoms and signs, including palpable mass, flank pain, hematuria, or renal failure. Although AML is almost always benign, a rare potentially malignant variant named epithelioid angiomyolipoma is described, which may mimic renal cell carcinoma (RCC).2

Characterization of solid renal neoplasms using MRI-based quantitative radiomics features

To assess the diagnostic value of magnetic resonance imaging (MRI)-based radiomics features using machine learning (ML) models in characterizing solid renal neoplasms, in comparison/combination with qualitative radiologic evaluation. Retrospective analysis of 125 patients (mean age 59years, 67% males) with solid renal neoplasms that underwent MRI before surgery. Qualitative (signal and enhancement characteristics) and quantitative radiomics analyses (histogram and texture features) were performed on T2-weighted imaging (WI), T1-WI pre- and post-contrast, and DWI. Mann-Whitney U test and receiver-operating characteristic analysis were used in a training set (n = 88) to evaluate diagnostic performance of qualitative and radiomics features for differentiation of renal cell carcinomas (RCCs) from benign lesions, and characterization of RCC subtypes (clear cell RCC [ccRCC] and papillary RCC [pRCC]). Random forest ML models were developed for discrimination between tumor types on the training set, and validated on an independent set (n = 37). We assessed 104 RCCs (51 ccRCC, 29 pRCC, and 24 other subtypes) and 21 benign lesions in 125 patients. Significant qualitative and quantitative radiomics features (area under the curve [AUC] between 0.62 and 0.90) were included for ML analysis. Models with best diagnostic performance on validation sets showed AUC of 0.73 (confidence interval [CI] 0.5-0.96) for differentiating RCC from benign lesions (using combination of qualitative and radiomics features); AUC of 0.77 (CI 0.62-0.92) for diagnosing ccRCC (using radiomics features), and AUC of 0.74 (CI 0.53-0.95) for diagnosing pRCC (using qualitative features). ML models incorporating MRI-based radiomics features and qualitative radiologic assessment can help characterize renal masses.

Nephrometry Scoring System Selects Candidates for Radical Nephrectomy versus Nephron-Sparing Surgery for Treatment of Renal Masses and Predicts Surgical and Oncological Outcome

Purpose: The study was designed to ensure the sensitivity of preoperative planning by applying radius, endophytic/exophytic, nearness to collecting system, anterior/posterior, and location to poles (RENAL) nephrometry scoring system on computed tomography films of patients having organ-confined solid and cystic renal tumors and to assess its correlation with the surgical technique by applying RENAL on the specimen intraoperative. Materials and Methods: Eighty-five patients with organ-confined solid and cystic renal masses underwent RENAL nephrometry system which was correlated with the surgical technique either radical or nephron-sparing surgery or the surgical and oncological outcome. Results: RENAL nephrometry scoring system shows high sensitivity with the type and outcome of surgery of resection of the renal tumors. Conclusion: RENAL nephrometry score system is an objective method to help in the decision of surgical approach to resect organ-confined solid and cystic renal tumors.

What family physicians should know about interventional radiology?

Interventional radiology (IR) is a rapidly evolving specialty. The minimally invasive nature of the procedures has led to a paradigm shift in treating many disease processes from conventional surgery to interventional techniques that have become the first choice and the preferred method for the treatment of peripheral vascular disease, many aortic pathologies, and venous diseases. Interventional oncology procedures have become widely available for the treatment of solid hepatic and renal tumors. This includes palliative techniques for many advanced malignancies, and fluid drainage that is exclusively performed by interventional radiologists in many hospitals all around the world. Women's health-related procedures such as uterine fibroid embolization, fallopian tube recanalization, and embolization for pelvic congestion syndrome have become attractive choices for many patients. Family physicians (FPs) are the main source of patient referral to hospitals. However, there is a notable knowledge deficiency of IR among FPs in Saudi Arabia. This may be due to poor communication between FP and IR or the lack of FP's awareness of IR procedures. This is a nonsystematic review to introduce some IR procedures to FPs pertinent to their practice to optimize patient referral and management with the use of IR services. We focused on the most commonly performed IR procedures paying special attention to their clinical indications, benefits, and alternatives.

Reducing radiation dose for multi-phase contrast-enhanced dual energy renal CT: pilot study evaluating prior iterative reconstruction.

Prior iterative reconstruction (PIR) uses spatial information from one phase of enhancement to reduce image noise in other phases. We sought to determine if PIR could reduce radiation dose while preserving observer performance and CT number at multi-phase dual energy (DE) renal CT. CT projection data from multi-phase DE renal CT examinations were collected. Images corresponding to 40% radiation dose were reconstructed using validated noise insertion and PIR. Three genitourinary radiologists examinedroutine and 40% dose PIR images. Probability of malignancy was assessed [from 0 to 100] with malignancy assumed at probability ≥ 75. Observer performance was compared on a per patient and per lesion level. CT number accuracy was measured. Twenty-three patients had 49 renal lesions (11 solid renal neoplasms). CT number was nearly identical between techniques (mean CT number difference: unenhanced 2 ± 2 HU; enhanced 4 ± 4 HU). AUC for malignancy was similar between multi-phase routine dose DE and lower dose PIR images [per patient: 0.950 vs. 0.916 (p = 0.356); per lesion: 0.931 vs. 0.884 (p = 0.304)]. Per patient sensitivity was also similar (78% routine dose vs. 82% lower dose [p ≥ 0.99]), as was specificity (91% routine dose vs. 93% lower dose PIR [p > 0.99]), with similar findings on a per lesion level. Subjective image quality was also similar (p = 0.34). Prior iterative reconstruction is a new reconstruction method for multi-phase CT examinations that promises to facilitate radiation dose reduction by over 50% for multi-phase DE renal CT exams without compromising CT number or observer performance.

Renal angiomyolipoma.

Angiomyolipoma is one of the most common benign solid renal tumors. We investigated the characteristics of renal angiomyolipomas and the clinical outcomes of patients in the last thirteen years. The medical records of the patients who underwent nephrectomy were reviewed retrospectively from July 2005 to May 2018. The laboratory data, radiology, and pathology reports were recorded. Patients diagnosed with angiomyolipoma were included in the study. A total of 28 patients were included in the study, eight of them male. The mean age of the patients was 55.89+14.49 years. The patients were treated with open and laparoscopic techniques. Partial nephrectomy was performed in 12 patients(42.85%). After pathological examination, 23 patients were diagnosed as fat rich, four patients as fat poor, and one as epithelioid angiomyolipoma. There were no recurrences in the follow-up 91.21+48.31 months. Angiomyolipoma is a rare renal tumor in daily urology practice. Clinicians must be aware of its complications and manage patients well.

Intra- and Interobserver Agreement of SUV SPECT Quantitative SPECT/CT Processing Software, Applied in Clinical Settings for Patients with Solid Renal Tumors.

Quantification tools for SPECT/CT are a field of ongoing research among hybrid imaging techniques. A recent multicenter study evaluating SUV SPECT software on phantoms showed that quantitative SPECT/CT is reproducible in Hybrid Viewer software. The aim of our study was to evaluate the intra- and interobserver agreement of quantitative SUV SPECT measurements in clinical settings for patients with solid renal tumors. Methods: The evaluation was part of a study that examined the role of 99mTc-sestamibi SPECT/CT in the characterization of solid kidney tumors and the differentiation of renal oncocytomas from renal cell carcinomas. Quantitative evaluation of SUV measurements was performed in Hybrid Viewer PDR, version 2.5. Forty-eight renal lesions were identified and examined twice by 2 independent readers. The agreement of the SUV measurements, concerning renal tumors and adjacent renal parenchyma, was evaluated using the intraclass correlation coefficient (ICC). Results: ICC for SUVmax measurements by the same reader was 97%-99% for solid renal tumors and 92%-98% for ipsilateral healthy renal parenchyma. ICC for SUVmax measurements between readers was 87%-89% for solid renal tumors and 72%-73% for ipsilateral healthy renal parenchyma. Estimated ICC for SUVmean measurements of solid renal tumors was 95%-98% for the same reader and 86%-89% between readers. Similar results were found for SUVpeak measurements. Conclusion: The high ICCs indicate a strong agreement among SUV measurements for patients with solid renal lesions undergoing 99mTc-sestamibi SPECT/CT, not only for measurements by the same reader but also for measurements between 2 different readers.

Imaging biomarkers based on multiphase CT data in differentiation of renal cell carcinoma

Background. Renal-cell carcinoma (RCC) is one of 10 mostly widely spread malignant tumors in the world. Recently scientists focused on investigation of new imaging biomarkers of RCC based on USG, CT, MRI and radionuclide examinations data in order to increase efficiency of current pathology diagnostics. The goal of this study was to evaluate an efficiency of application of the novel biomarkers based on multiphase CT in differential diagnostics of RCC. Materials and methods. In total 120 patients with solid renal tumors >4 cm in greatest dimension in whom nephrectomy followed by pathological analysis were enrolled into this retrospective study: 84 (70,0%) with RCC, 14 (11,67%) with transitional cell carcinoma of renal pelvis and 22 (18,33%) with benign renal tumors. We analyzed and compared pathologic and multiphase CT data. Results. Using of signal intensity with threshold 54,80 HU allowed to differentiate RCC from other renal tumors with sensitivity and specificity accordingly 98,8% and 69,4% (AUC=0,844, 95% CI=0,746–0,942, р<0,001) on excretory CT images. Differentiation of RCC and benign renal tumors using signal intensity with threshold of 61,84 HU demonstrated 79,8% sensitivity and 63,6% specificity (AUC=0,745, 95% CІ=0,599–0,891, р<0,001) on excretory CT images. Differentiation of conventional RCC histologic subtype from non-conventional using signal intensity of nephrographic CT images with threshold 79,39 HU was possible with 71,7% specificity and 54,8% sensitivity (AUC=0,718, 95% CІ=0610–0,826, р=0,001). Identification of papillary and chromophobe subtypes as well as Fuhrman grades of clear-cell RCC was also possible. Conclusions. Application of radiodensity of tumor measured using multiphase CT as diagnostic imaging biomarker of solid RCC is valuable clinical tool for differentiation of current pathology, its histologic subtypes and Fuhrman grades. The drawback of the method is relatively high radiation exposure of the patient.

Management of Small Renal Masses

The rise in incidentally discovered enhancing solid renal tumors has spurred the development of new approaches to managing this unique clinical entity known as the small renal mass (SRM). These approaches are grounded on a better understanding of the natural history of SRM, with the goal to reduce the morbidity associated with their management and avoid overtreatment. In this chapter, we review the body of evidence pertaining to the classification and clinical management of SRMs with respect to diagnosis, treatment, and follow-up. In addition, we discuss the controversies and active areas of development for this rapidly evolving field that strides towards a precision medicine paradigm. This review contains 6 figures, 6 tables and 63 references Keywords: Small renal mass, renal cell carcinoma, radical nephrectomy, renal tumor biopsy, active surveillance, natural history, oncocytoma, robotic surgery, partial nephrectomy

Specific computed tomography imaging characteristics of congenital mesoblastic nephroma and correlation with ultrasound and pathology

Congenital mesoblastic nephroma (CMN) is a common solid renal tumor in the neonate. Congenital mesoblastic nephroma can be divided into classic, cellular, and mixed types. The prognosis of CMN is very optimistic. But CMN can easily be misdiagnosed as the other malignant renal tumors by radiology. However, no studies have described the computed tomography (CT) imaging appearance of CNM in detail. The objective of this study is retrospective analyses of the multislice CT characteristics of CMN and their corresponding ultrasound findings and pathology. This retrospective study reviewed the enhanced CT images of the CMNs and other renal tumors in children younger than 1 year in the past 10 years from the First Affiliated Hospital of Sun Yat-sen University. Two radiologists had noted the CT imaging characteristics of these images. t-test and Fisher's exact test were used in the comparison of imaging characteristics between the CMNs and other renal tumors. Compared with other malignant renal tumors, the CMNs tend to appear as smaller round masses without clear coverage or clear boundary with the kidney in CT images (P<0.01). The intratumor pelvis and the double-layer sign are the specific characteristics of CMNs (P<0.01). The gender, quality of tumor (solid or solid-cystic), character of enhancement (homogeneous or heterogeneous enhancement), peri-renal hemorrhage, or peripheral lymph node enlargement showed no statistical significance (P>0.05) between CMNs and other renal tumors. The appearances of CMN with classic components in the CT images are relevant to the pathological findings. The intratumor pelvis is caused by the classic components of CMN growing to encapsulate the pelvis. The double-layer sign in CT image correlates with the specific hypoechoic ring in ultrasound, which is caused by the slow blood flow and delay contrast agent filling in the blood sinus located in the peripheral part of the tumor. The differential diagnosis of CMN should include the other solitary renal tumors such as Wilms' tumor, clear-cell sarcoma of the kidney, and rhabdoid tumor of the kidney. The unclear coverage and unclear boundary with the kidney, the intratumor pelvis, and double-layer sign after contrast were specific CT imaging characteristics of CMN.

Diagnostic Imaging for Solid Renal Tumors: A Pictorial Review.

The prognosis of renal tumors depends on histologic subtype. The increased use of abdominal imaging has resulted in an increase in the number of small renal incidentaloma in recent decades. Of these incidentally discovered tumors, 20% are benign lesions warranting conservative management, but most are renal cell carcinomas that warrant a more aggressive therapeutic approach due to their malignant potential. Dedicated diagnostic renal imaging is important for characterization of renal tumors to facilitate treatment planning. This review discusses the ability to detect and differentiate renal cell carcinoma subtypes, angiomyolipoma and oncocytoma based on ultrasound imaging, computed tomography, multiparametric magnetic resonance, and nuclear imaging.

Noninvasive phenotyping of renal tumors-current state of the art

Due to often overlapping imaging features, solid renal tumors pose adiagnostic challenge. In addition, personalized therapies require exact tumor subtyping. To reduce complications, this should ideally be performed noninvasively. The aim of this work was to provide an overview on the current state of the art and new developments in the field of noninvasive radiological phenotyping of the most common types of adult renal tumors. Multimodal and multiparametric imaging already enables an exact, noninvasive differentiation between many types of benign and malignant renal tumors. Concerning problematic cases, as well as for amore detailed characterization of renal tumors (tumor grade, genetic factors), promising new techniques, or techniques that have not previously been used for this purpose, such as texture analysis, computer-based "deep feature classifications", iodine quantification or MR spectroscopy, are being investigated.

The Probability of Aggressive Versus Indolent Histology Based on Renal Tumor Size: Implications for Surveillance and Treatment

BackgroundWhile the probability of malignant versus benign histology based on renal tumor size has been described, this alone does not sufficiently inform decision-making in the modern era since indolent malignant tumors can be managed with active surveillance. ObjectiveTo characterize the probability of aggressive versus indolent histology based on radiographic tumor size. Design, setting, and participantsWe evaluated patients who underwent radical or partial nephrectomy at Mayo Clinic for a pT1-2, pNx/0, M0 solid renal tumor between 1990 and 2010. Pathology was reviewed by one genitourinary pathologist. High-grade clear-cell renal cell carcinoma (RCC), high-grade papillary RCC, collecting duct RCC, translocation-associated RCC, hereditary leiomyomatosis RCC, unclassified RCC, and malignant non-RCC tumors were all considered aggressive, as well as any tumors demonstrating coagulative necrosis (except low-grade papillary RCC) or sarcomatoid differentiation. The remaining benign and malignant tumors were considered indolent. Outcome measurements and statistical analysisCancer-specific survival (CSS) was estimated using the Kaplan-Meier method. Logistic regression models were used to estimate the probability of malignant and aggressive histology based on tumor size. Sex-stratified analyses were also performed. Results and limitationsOf the 2650 patients included, there were 1860 patients with indolent tumors (300 benign; 1560 malignant) and 790 with aggressive tumors. The 10-yr CSS was 96% for indolent malignant tumors and 81% for aggressive malignant tumors. The predicted percentages of any malignant histology as well as aggressive histology increased with tumor size. Specifically, 2cm, 3cm, and 4cm tumors have an estimated 84%, 87%, and 88% likelihood of malignancy, respectively, and an 18%, 24%, and 29% likelihood of aggressive histology, respectively. For any given tumor size, men had a greater chance of aggressive histology than women. Potential limitations of this observational surgical cohort include selection bias. ConclusionsWe present tumor size-based estimates of the probability of aggressive histology for renal masses. This information should be useful for initial patient counseling and management. Patient summaryActive surveillance is an option for kidney masses, even if they are malignant. Beyond knowing whether the mass is benign or cancer, it is important to know whether or not it is an aggressive tumor. This study presents tumor size-specific and sex-specific estimates of the probability of cancer overall and aggressive cancer among patients with a kidney mass in order to aid with initial decision-making.

Renal tumor structured reporting including nephrometry score and beyond: what the urologist and interventional radiologist need to know.

The purpose of this paper is to describe cross-sectional imaging anatomic and morphologic parameters of solid renal tumors that urologists and interventional radiologists need for precise management, review the commonly used terms and descriptors of those parameters, and suggest a comprehensive reporting system for detected masses.

Spontaneous Fatal Rupture of a Large Pseudoaneurysm within a Renal Angiomyolipoma following Incomplete Embolization in a Patient with Bilateral Renal Angiomyolipomas

Angiomyolipoma (AML)—a frequently seen solid renal tumor—is the most common benign tumor of the kidney. It was considered to be hamartomatous in origin and is now considered to be a member of the family of perivascular epithelioid cell (PEComa).[1] Classically thought to be associated with tuberous sclerosis that is an autosomal dominant disease with TSC1 or TSC2 gene mutation, around 80% AMLs may present sporadically.[1] They are also seen in patients with lymphangiomyomatosis and included in its diagnostic criteria.[2] Clinically, the tumor has myriad of presentations ranging from being completely asymptomatic at the time of diagnosis to abdominal pain, hematuria, recurrent urinary tract infection, and intratumoral bleed that can be occasionally massive requiring urgent embolization or nephrectomy.[3] On ultrasound AMLs appear as markedly hyperechoic to hypoechoic depending on the fat content. Though they are more frequently echogenic compared with renal cell carcinoma, overlap in imaging features can occur.[4] On color Doppler, pseudoaneurysms are seen as anechoic structure showing internal turbulent to-and-fro motion.[5] On computed tomographic (CT) scan, the diagnosis of renal AML depends on the detection of intralesional fat.[6]