Ultrasound-Guided Core Needle Biopsy for Renal Sinus Masses: A Valuable Tool in the Preoperative Evaluation of Urologic Tumors

Ultrasound-Guided Core Needle Biopsy for Renal Sinus Masses: A Valuable Tool in the Preoperative Evaluation of Urologic Tumors | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Ultrasound-Guided Core Needle Biopsy for Renal Sinus Masses: A Valuable Tool in the Preoperative Evaluation of Urologic Tumors Liang Xia, Zeng Xiantao, Su Miaojiao, Hong Zhiliang, Wu Songsong This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6942528/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Background The renal sinus's complex anatomy challenges imaging diagnosis. Ultrasound-guided biopsy shows promise for renal sinus masses due to its real-time, radiation-free, and cost-effective advantages, but its efficacy and safety need validation. Objective To evaluate the diagnostic performance, safety, and clinical impact of ultrasound-guided percutaneous core needle biopsy for renal sinus masses. Materials and Methods A retrospective analysis was conducted on 51 patients who underwent ultrasound-guided renal sinus biopsy at a tertiary medical center between April 2010 and October 2020. Inclusion criteria were renal sinus masses with indeterminate imaging features. Diagnostic yield, complications (graded by the Clavien–Dindo classification), and treatment plan modifications were recorded. Univariate logistic regression analysis was used to identify factors associated with complications. Results The overall diagnostic yield was 90.2% (46/51), with malignant lesions accounting for 88.2% (45/51), including urothelial carcinoma of the renal pelvis (43.1%, 22/51) and clear cell renal cell carcinoma (31.4%, 16/51). Benign lesions accounted for 11.8% (6/51). The complication rate was 7.8% (4/51), including perirenal hematoma and gross hematuria (Clavien–Dindo grade I–II), with no cases of needle tract seeding or severe complications. Biopsy results altered treatment plans in 23.5% (12/51) of patients, and unnecessary surgery was avoided in 7.8% (4/51). Tumor size, location, number of needle passes, and tract ablation were not significantly associated with complications (all p > 0.05). Conclusion Ultrasound-guided percutaneous biopsy of renal sinus lesions demonstrates high diagnostic efficacy (90.2%) and safety (complication rate: 7.8%) in complex renal sinus diseases. It enables precise clinical decision-making and helps avoid overtreatment. Its advantages of real-time imaging and absence of radiation make it a valuable tool in the management of renal tumors. Ultrasound-guided biopsy renal sinus mass diagnostic accuracy complication rate urothelial carcinoma individualized treatment image-guided intervention Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Introduction Image-guided percutaneous biopsy plays a pivotal role in the management of oncology patients, contributing not only to initial diagnosis and tumor staging, but also to treatment monitoring, assessment of residual lesions, and confirmation of tumor recurrence [ 1 ] . It also provides valuable information for patients with comorbidities who may not be suitable candidates for surgery. These patients may benefit from alternative therapeutic approaches such as active surveillance and thermal ablation. Moreover, with the advent of targeted biologic therapies—particularly in the era of personalized and precision medicine—obtaining high-quality tissue samples has become essential for molecular subtyping and biomarker testing [ 2 ][ 3 ][ 4 ] . Among various guidance modalities, ultrasound (US) and computed tomography (CT) are the most widely used imaging techniques. Owing to its convenience, real-time visualization, and lack of ionizing radiation, ultrasound has become one of the preferred imaging guidance methods in clinical practice [ 5 ] . In recent years, advances in technology have expanded the role of ultrasound guidance in biopsies of lesions located in anatomically complex regions. However, unlike renal parenchymal lesions, biopsies of the renal sinus are technically challenging due to its intricate anatomy and proximity to vital structures such as blood vessels and the ureter [ 6 ][ 7 ] . Nevertheless, ultrasound-guided renal sinus biopsy offers promising diagnostic potential for both benign and malignant lesions, owing to its real-time visualization and precise targeting capabilities [ 8 ] . A variety of benign and malignant tumors can arise in the renal sinus. Malignant tumors include transitional cell carcinoma (TCC) of the renal pelvis, sinus-invading renal cell carcinoma (RCC), lymphoma, and metastatic tumors [ 9 ] . Benign lesions include angiomyolipoma (AML), perirenal cysts, and inflammatory pseudotumors [ 10 ] . TCC of the renal pelvis is the most common malignancy of the renal sinus, accounting for over 90% of all upper urinary tract urothelial carcinomas. Its 5-year survival rate is largely influenced by the tumor stage [ 11 ] . Lymphoma may also involve the renal sinus, presenting as either diffuse infiltration or a focal mass, and can be difficult to distinguish from other renal sinus lesions [ 12 ] . The complex histological spectrum of renal sinus lesions and the heterogeneity of tumors present significant diagnostic challenges. In many cases, imaging alone is insufficient to reliably differentiate benign renal masses, indolent renal cell carcinomas, and aggressive subtypes [ 13 ] . Accurate diagnosis is therefore critical for guiding appropriate treatment strategies. Previous studies have demonstrated that ultrasound-guided biopsy of renal masses has a high success rate in obtaining sufficient high-quality tissue samples, with a low complication rate [ 14 ][ 15 ][ 16 ][ 17 ] . However, systematic studies on percutaneous biopsy of renal sinus masses remain scarce, particularly those integrating data on diagnostic accuracy and safety. This presents an opportunity for further investigation into the clinical significance of ultrasound-guided biopsy of renal sinus masses. At our institution, clinical preference has allowed us to perform a relatively large number of ultrasound-guided biopsies of renal sinus masses. This has enabled a comprehensive analysis of the diagnostic performance and safety profile of ultrasound-guided biopsy of renal sinus masses in a relatively large cohort. This study aims to retrospectively analyze ultrasound-guided core needle biopsy cases of renal sinus masses to assess the diagnostic efficacy, technical feasibility, and safety of the procedure, and to explore its impact on clinical management. Materials and Methods Ethical Statement This retrospective study was approved by the Institutional Review Board of Fujian Provincial Hospital, with permission granted for chart review and a waiver of written informed consent. Study Population Using the ultrasound workstation (Lanwon, version: V7 Build1560312), we retrospectively identified patients who were referred to our ultrasound department between April 2010 and October 2020 for percutaneous ultrasound-guided core needle biopsy of renal sinus masses with indeterminate imaging features. A preliminary screening using the keywords "kidney" and "biopsy" identified a total of 133 patients. Of these, 71 patients who underwent renal parenchymal biopsies (i.e., targeting the cortex or medulla) rather than renal sinus biopsies (i.e., targeting peripelvic fat, vessels, and lymphatics, which appear hyperechoic on renal ultrasound; see Figure 1) were excluded. We subsequently reviewed the electronic medical records of 62 patients who met the criteria for ultrasound-guided renal sinus core needle biopsy. Data collected included demographic information (age, sex); mass characteristics (size, location, solid or cystic-solid composition, RENAL score); procedural details (number of biopsy cores, total specimen length, use of needle tract ablation or embolization, and complications); pathological diagnosis (histopathology or surgical pathology); and subsequent clinical management (diagnostic yield, histological subtype, post-biopsy imaging follow-up for late complications or needle tract seeding, follow-up duration, need for repeat biopsy, and treatment outcomes). For patients who subsequently underwent surgical resection, the histological findings from the biopsy were compared with the final surgical pathology to determine diagnostic accuracy. Eleven patients were excluded due to incomplete clinical data (missing imaging or medical records), resulting in a final cohort of 51 eligible patients(Figure 2). All patients were evaluated by a multidisciplinary tumor board at our institution, comprising specialists in medical oncology, urology, diagnostic radiology, and interventional ultrasound. Patients were considered eligible for renal sinus biopsy if they met at least one of the following criteria: (1) clinical history and prior imaging studies (i.e., contrast-enhanced CT or magnetic resonance imaging [MRI]) suggested a renal sinus mass without a definitive benign or malignant diagnosis, or (2) histological confirmation was required to guide clinical treatment, such as targeted therapy. Equipment Ultrasound examinations were performed using Philips iU22 and GE Vivid 7 Dimension color Doppler systems, equipped with linear-array transducers (5–12 MHz) and convex-array transducers (2–5 MHz). Ultrasound-Guided Renal Sinus Biopsy All patients underwent routine preoperative laboratory tests, including complete blood count, biochemical profile, and coagulation function assessment, as well as imaging evaluations with CT or MRI. The interventional radiologist carefully reviewed preoperative imaging to assess the location of the renal sinus lesion and its relationship to adjacent structures. A pre-biopsy ultrasound scan was performed, with contrast-enhanced ultrasound (CEUS) used to identify solid components as biopsy targets. The puncture site was then routinely disinfected and draped, followed by local infiltration anesthesia. Under real-time in-plane ultrasound guidance, a 17G coaxial introducer needle (KIM-16; ITP, BARD Company, USA) was inserted into the target lesion. Using an 18G semi-automatic biopsy needle (BIM-18; ITP), 1–4 core specimens were obtained through the coaxial sheath(Figure 3). If bleeding was observed during the biopsy, a small amount of thrombin was injected through the coaxial sheath to embolize the needle tract. Needle Tract Ablation Procedure Some patients underwent needle tract thermal ablation post-biopsy, with the procedure performed at the discretion of the operator based on perceived bleeding risk. A bipolar radiofrequency (RF) ablation device was used as the biopsy needle during this procedure. After selecting the puncture site, a 15G coaxial introducer needle was inserted to the lesion margin under in-plane ultrasound guidance. After removal of the inner stylet, a 16G core-cutting biopsy needle (Zhejiang Curaway Medical Technology Inc., China) was loaded into an automatic biopsy gun to obtain tissue samples. The inner core was then reinserted, and the RF generator was activated to deliver thermal ablation via the working electrode at the tip of the outer sheath. The needle was held in place until the target temperature was reached, then slowly withdrawn until fully removed from the kidney. The number of biopsy passes was determined subjectively by the operator based on the gross appearance of the specimens, with no on-site pathological evaluation. All biopsy procedures were performed by two senior ultrasound-guided interventional physicians (W.S.S., 20 years of experience; Y.J.C., 15 years of experience). All procedures were performed under local anesthesia. After the procedure, manual compression was applied to the puncture site for 5 minutes, followed by sterile dressing. Patients were observed for 30–60 minutes and underwent ultrasound to screen for post-procedural bleeding before discharge. Patients remained on bed rest for 2 hours postoperatively without pharmacological intervention and were discharged the following day after overnight observation. All biopsy specimens were analyzed by a urogenital pathologist with 15 years of experience (W.C.), and were subsequently used to assess for post-procedural complications. Evaluation Criteria The complexity of renal masses was assessed using the RENAL nephrometry score, based on the method proposed by Kutikov and Uzzo [18] ; postoperative complications were graded according to the Clavien–Dindo classification system [19] . Pathological evaluation: A diagnosis was considered successful if the pathology revealed malignancy, or if a benign diagnosis was confirmed by ≥12 months of stable imaging follow-up. Conversely, a diagnosis was deemed inaccurate if a lesion initially diagnosed as benign showed progression on follow-up imaging or was later found to contain malignant components on repeat biopsy or surgery. Statistical Analysis Statistical analyses were performed using SPSS software, version 26.0 (IBM Corp., Armonk, NY, USA). Categorical variables are presented as frequencies and percentages, while continuous variables are expressed as medians with ranges. The overall diagnostic success rate and complication rate of ultrasound-guided percutaneous biopsy of renal sinus masses were calculated. To identify factors associated with diagnostic success and complications, univariate logistic regression using Firth’s penalized likelihood method was employed. Variables included maximum tumor diameter (>30 mm vs. ≤30 mm), tumor location (upper/middle vs. lower pole), proximity to the renal hilum, number of punctures (1–4), and whether tract ablation was performed (for complication analysis). Results were reported as odds ratios (ORs) with 95% confidence intervals (CIs). Statistical significance was defined as a two-sided p -value of <0.05. Results Patient and Tumor Characteristics A total of 51 patients who underwent ultrasound-guided percutaneous core needle biopsy of renal sinus masses were included in the study. Of these, 29 were male (56.86%) and 22 were female (43.14%). The median age was 63 years (range: 19–85 years). The median maximum tumor diameter was 37 mm (range: 13–106 mm). Heterogeneous enhancement was observed in 56.86% of lesions (29/51). According to the RENAL nephrometry scoring system, 88.23% of lesions (45/51) were classified as highly complex (scores of 10–12), and 11.77% were moderately complex (scores of 7–9); no low-complexity tumors were identified. Baseline patient characteristics are summarized in Table 1. Diagnostic Performance and Histopathological Findings In this study, the overall diagnostic success rate of ultrasound-guided percutaneous biopsy of renal sinus masses was 90.20% (46/51); 5 cases (9.80%) yielded non-diagnostic results due to insufficient tissue or necrosis. In two cases, the initial biopsy yielded only one tissue core, which was insufficient for diagnosis; both were later confirmed by surgery to be urothelial carcinoma of the renal pelvis. One lesion exhibited extensive central necrosis with no viable area on CEUS, and was confirmed postoperatively as clear cell renal cell carcinoma (Fuhrman grade III). In one case, severe fibrosis in the biopsy specimen precluded diagnosis; laparoscopic biopsy later confirmed a solitary fibrous tumor. One case was complicated by intraoperative bleeding that interfered with sampling; a second CT-guided biopsy confirmed metastatic adenocarcinoma originating from the lung. Univariate logistic regression analysis showed no significant associations between diagnostic success and tumor size (>30 mm vs. ≤30 mm), tumor location (upper/middle vs. lower pole), proximity to the renal hilum, or number of biopsy passes (1–4) (Table 3). Details of all 51 cases are summarized in Table 2. Complication Analysis The overall complication rate of ultrasound-guided percutaneous biopsy of renal sinus masses was 7.84% (4/51), including three cases of perirenal hematoma (15–20 mm in diameter) and one case of gross hematuria, all classified as Clavien–Dindo grade I–II. Details of management and outcomes are as follows: Case 1 : Immediate postoperative ultrasound revealed a 15 mm hematoma. The patient remained hemodynamically stable and was managed with local compression and extended bed rest (6 hours). The hematoma resolved spontaneously within one week, as confirmed on follow-up ultrasound. Case 2 : Minor bleeding occurred during the procedure. Thrombin (500 IU) was injected via the coaxial sheath to embolize the needle tract. The patient was observed for 24 hours postoperatively without the need for further intervention. Case 3 : The patient developed mild flank pain 24 hours post-procedure. Ultrasound confirmed a 20 mm perirenal hematoma. Symptomatic treatment with analgesia and an extended hospital stay (48 hours) was provided. The hematoma resolved completely by one-month follow-up. Case 4 (hematuria) : Gross hematuria developed 6 hours after biopsy. The patient was treated with intravenous tranexamic acid and absolute bed rest. Hematuria resolved within 24 hours without evidence of coagulopathy or thrombotic events. No major complications such as arteriovenous fistula, significant hemorrhage, or nephrectomy were observed. Univariate logistic regression analysis showed no significant associations between complication occurrence and tumor size (>30 mm vs. ≤30 mm), tumor location (upper/middle vs. lower pole), proximity to the renal hilum, number of biopsy passes (1–4), or needle tract ablation (Table 4). All available post-biopsy axial imaging data were retrospectively reviewed to evaluate for delayed complications and needle tract seeding. As of the time of data collection, five patients had no imaging or clinical follow-up. Among the remaining 46 patients, the median imaging follow-up period was 5 years (range: 0.2–12 years). No imaging findings suggestive of delayed complications or tumor seeding along the biopsy tract were identified. Impact on Clinical Decision-Making Biopsy results altered the treatment strategy in 23.5% (12/51) of patients, including 7.8% (4/51) in whom unnecessary surgery was avoided(Figure 5、Suppl. Fig. 1). Among the 46 patients with available treatment data, 29 underwent surgery alone—25 underwent radical nephrectomy and 4 underwent partial nephrectomy(Suppl. Fig. 2、Suppl. Fig. 3、Suppl. Fig. 4). Three patients received ablation therapy, two received chemotherapy, and two were managed with active surveillance. Ten patients underwent combination therapy, including chemotherapy plus surgery in seven cases and chemotherapy plus radiotherapy in three (Figure 4). Table 1 Patient and Tumor Characteristics Patients Characteristic N=51 N % Age (years) Median 63 Range (mean) 19-85（64.29） Gender Female 22 43.14 Male 29 56.86 Maximum Diameter Median 31 Range (mean) 13-78（30.09） Laterality Left 27 52.94 Right 24 47.06 Enhancement Pattern Homogeneous 22 43.14 Heterogeneous 29 56.86 RENAL nephrometry score Low（4-6） 0 0 Moderate（7-9） 6 11.76 High（10-12） 45 88.24 Table 2 Pathological Results Diagnostic N % Benign Angiomyolipoma 2 3.92 Eosinophilic Adenoma 2 3.92 Solitary Fibrous Tumor 1 1.96 IgG4-related Kidney Disease 1 1.96 Malignant Transitional Cell Carcinoma (TCC) 22 43.14 RCC, clear cell 16 31.37 RCC, papillary 2 3.92 RCC, chromophobe 1 1.96 Metastatic 3 5.88 Lymphoma 1 1.96 Table 3 Univariate Logistic Regression Model for Diagnostic Success Rate Parameter level Successful Diagnoses / Total OR （ CI ） P -value Maximum diameter ≤30 mm 4/33 — — >30 mm 1/18 0.43(0.04–4.12) 0.64 Location Upper 2/7 — — Mid 3/32 0.26(0.03 - 1.95) 0.25 Lower 0/12 0.08 (0.00 - 1.97) 0.20 Nearness to hilum Not near 2/31 — — Near 3/20 2.56（0.39 - 16.78） 0.34 Biopsy cores (N) 1 2/6 — — 2 3/19 0.38 (0.01 - 0.50) 0.19 3 0/17 0.05 (0.00 - 1.19) 0.10 4 0/9 0.09 (0.00 - 2.29) 0.27 Table 4 Univariate Logistic Regression Model for Complications Parameter level Complications / Total OR （ CI ） P -value Maximum diameter ≤30 mm 2/33 — — >30 mm 2/18 1.94 (0.25–15.07) 0.61 Location Upper 1/12 — — Mid 3/32 1.14 (0.13 - 10.18) 0.56 Lower 0/7 0.54 (0.02 - 6.23) 1.00 Nearness to hilum Not near 2/31 — — Near 2/20 0.33（0.02, 3.52） 0.42 Biopsy cores (N) 1 1/6 — — 2 2/19 0.59 (0.04 - 5.15) 0.63 3 0/17 0.10 (0.00 - 3.07) 0.32 4 1/9 0.63(0.03 - 6.82) 1.00 Tract ablation Yes 4/35 — — No 0/16 0.22(0.03 - 3.74) 0.30 Discussion Our retrospective analysis of 51 cases undergoing ultrasound-guided percutaneous renal sinus core needle biopsy demonstrated that this technique offers high diagnostic efficacy and favorable safety in patients with highly complex renal masses. The overall diagnostic yield was 90.20%, with malignant lesions accounting for 88.24% and benign lesions for 11.76%. Moreover, the overall complication rate was only 5.88%, all of which were minor, with no major complications observed. Compared with previous literature, our findings further support the value of ultrasound-guided renal sinus biopsy in achieving accurate diagnosis and informing therapeutic decision-making. Diagnostic Performance and Histopathological Correlation Image-guided percutaneous renal parenchymal biopsy has been extensively reported, with diagnostic accuracy ranging from 85.5% to 97.1%, and major/minor complication rates reported at 0–0.9% and 1.8–20.3%, respectively [20] [21] [22] [23] [24] [25] [26] [27] [28] [29] . Furthermore, Yang et al [30] . compared the efficacy of fine-needle aspiration (FNA) and core needle biopsy, and found that core biopsy had a significantly higher diagnostic yield (88% vs. 72%, p < 0.01). However, studies focusing on renal sinus biopsy remain limited. Although MRI guidance is widely regarded as suitable for biopsies of deep or anatomically complex regions due to its superior soft-tissue contrast, our findings demonstrate that ultrasound-guided biopsy of the renal sinus achieves a comparable diagnostic accuracy (90.2%) to MRI-guided biopsy (90–96%). The exclusive use of core needle biopsies in our cohort may partially explain the high diagnostic rate. This result may be attributed to the advantages of real-time ultrasound imaging, which enables multiplanar observation and contrast-enhanced targeting. In particular, for hypervascular renal sinus lesions—56.86% of tumors in this study exhibited heterogeneous enhancement—CEUS facilitates precise localization of viable tissue, thereby avoiding necrotic or cystic regions and improving sampling accuracy. Moreover, US guidance circumvents the high cost and operational complexity of MRI systems, making it more suitable for resource-limited clinical settings. Univariate logistic regression analysis revealed no significant association between biopsy success and tumor size (>30 mm vs. ≤30 mm, OR = 0.43, 95% CI: 0.04–4.12, p = 0.64), location (upper/mid vs. lower pole), proximity to the renal hilum, or the number of biopsy passes (1–4). The five biopsy failures (9.80%) were attributed to limited specimen volume, intratumoral necrosis, and fibrosis. Notably, 88.24% of tumors in our study were classified as highly complex (RENAL score 10–12), and 56.86% demonstrated heterogeneous enhancement. Despite this, a high diagnostic rate was maintained, suggesting that ultrasound guidance is a technically reliable approach even in complex renal sinus lesions. Safety and Complication Analysis The overall complication rate in this study was 7.84%, all of which were classified as minor (Clavien-Dindo grade I–II), including perirenal hematoma and gross hematuria. No severe complications requiring additional intervention or needle tract seeding were observed, consistent with previous reports of ultrasound-guided percutaneous renal biopsy (3%–10%). Although the renal sinus is anatomically complex, being adjacent to the renal hilum vessels and ureter, all hematomas were small (≤20 mm) and resolved completely with local compression, thrombin sealing of the needle tract, or hemostatic medication, suggesting a manageable risk profile for puncture in this area. Formation of perirenal hematoma may be attributed to minor vascular injury along the puncture path; however, the real-time dynamic imaging capability of ultrasound allows for adjustment of the needle trajectory to avoid major vascular branches, thereby limiting hematoma expansion. Gross hematuria may result from minor injury to the collecting system or renal pelvic mucosa. In this study, all cases were effectively resolved within 24 hours with intravenous tranexamic acid and strict bed rest. The prompt resolution of these complications underscores the potential advantage of ultrasound guidance in minimizing severe bleeding. It is worth noting that the renal sinus has been infrequently selected as a biopsy route in clinical practice, primarily due to its proximity to vital vascular structures and the potential risk of tumor seeding along the needle tract [31] . Literature reports indicate a needle tract seeding rate of 0.01% to 6% following renal biopsy [13] . Some cases are identified during routine pathological evaluation after nephrectomy, while in patients without surgical treatment, the true incidence may be underestimated due to delayed clinical presentation or pre-mortem unmanifested progression [32] . Repeated sampling using the same needle in a single patient may inadvertently implant microscopic tumor cells. Consequently, renal sinus biopsy has not been widely recommended in international guidelines, and its safety remains a subject of ongoing concern. Nevertheless, univariate analysis in this study revealed no significant association between complication rates and tumor size, number of needle passes, or needle tract ablation. Operator experience (e.g., precise selection of avascular paths) and standardized protocols (e.g., coaxial needle systems, immediate post-procedural tract ablation) may be key factors in reducing the risk of perirenal hematoma and hematuria. In addition, to prevent tumor seeding, all procedures in this study employed coaxial needle systems with immediate tract ablation. Follow-up imaging revealed no evidence of tract seeding or delayed complications. This may have contributed to the absence of such complications in our cohort. Although the follow-up period was limited, further studies with larger samples and extended observation are needed to assess the long-term risk of seeding. Impact on Clinical Decision-Making Renal biopsy not only serves diagnostic purposes but also directly informs treatment decisions. In our study, biopsy results led to a change in the therapeutic strategy for 23.53% of patients. Notably, four patients (7.84%) were spared unnecessary surgery due to a confirmed benign diagnosis, underscoring the role of ultrasound-guided biopsy in personalized treatment planning. With the increasing use of targeted and immunotherapies in recent years, pathological confirmation has become crucial for selecting optimal treatment strategies. In our cohort, urothelial carcinoma of the renal pelvis accounted for 43.14% of all malignant cases—substantially differing in management from renal cell carcinoma. While the former typically requires chemotherapy and ureterectomy, the latter may be managed with partial nephrectomy as a first-line option. These findings support the assertion by Gupta et al [33] . that image-guided biopsy should be an integral component of renal tumor management. In 88.23% of malignant cases, accurate histological subtyping—primarily urothelial carcinoma (43.14%) and clear cell renal cell carcinoma (31.37%)—provided crucial guidance for targeted therapy selection and surgical planning. Our results demonstrate that ultrasound-guided percutaneous renal sinus biopsy offers essential information for individualized therapy, helping to avoid overtreatment and optimize patient outcomes. In cases of renal sinus lesions with inconclusive imaging findings, suspected metastases requiring molecular subtyping for targeted therapy, or indeterminate lesions under active surveillance, biopsy confirmation is critical. Ultrasound-guided biopsy serves as a preferred diagnostic tool, particularly for patients with multiple comorbidities or elevated surgical risk. Study Limitations This study has several limitations. First, as a single-center retrospective analysis, the relatively small sample size may limit the statistical power, and the inclusion of cases from a single institution—based on imaging uncertainty prior to biopsy—could introduce selection bias, potentially leading to an overestimation of the diagnostic yield. Second, the loss to follow-up in five patients may have compromised the completeness of delayed complication assessment. Additionally, the relatively short follow-up period in some cases precluded a comprehensive evaluation of the long-term safety of the procedure, including the potential risk of needle tract seeding. Not all cases were confirmed by surgical pathology (only 39 patients underwent surgery), which may have resulted in an overestimation of diagnostic accuracy. Furthermore, the influence of operator experience on procedural outcomes was not assessed. This study also did not include a direct comparison with CT- or MRI-guided renal biopsy, which limits conclusions regarding the relative diagnostic performance of different imaging modalities. Future prospective, multicenter studies are warranted to validate these findings. In addition, integrating ultrasound elastography or artificial intelligence-assisted localization may help improve the visualization and targeting of deep-seated lesions. Although no needle tract seeding was observed during a median follow-up of five years in this study, longer-term data are needed to fully assess the risk of rare complications. Conclusion Ultrasound-guided percutaneous core needle biopsy of renal sinus masses is a safe, efficient, and cost-effective technique that provides critical diagnostic information for complex renal sinus lesions and supports informed clinical decision-making. Despite anatomical challenges and potential sample heterogeneity, its advantages—particularly the absence of radiation exposure and real-time dynamic imaging—underscore its important role in renal tumor management. With continued technological innovation and multidisciplinary collaboration, this approach holds promise for further optimizing clinical decision-making pathways in the management of renal tumors. Abbreviations US ：ultrasound CT ：computed tomography MRI ：magnetic resonance imaging CEUS ：contrast-enhanced ultrasound CI ：confidence interval OR ：odds ratio RF ：radiofrequency TCC ：transitional cell carcinoma RCC ：renal cell carcinoma AML ：angiomyolipoma Declarations Funding The author(s) declare that financial support was received for the research, authorship, and/or publication of this article. Fujian Science and Technology Innovation Joint Fund project climbing project (2023Y9332). Conflict of interest The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest Acknowledgments The authors are thankful to Fujian Provincial Hospital and Fujian Medical University for their management of our patient database. The authors are thankful to Song-Song Wu for helping critically revise the manuscript for important intellectual content and helping collect data and design the study. Author Contribution Liang Xia: Conceptualization, Data curation, Formal Analysis, Investigation, Methodology, Software, Validation, Visualization, Writing – original draft, Writing – review & editing. Zeng Xiantao: Conceptualization, Data curation, Investigation, Writing – review & editing. Su Miaojiao: Conceptualization, Data curation, Methodology, Writing – review & editing. Hong Zhiliang: Methodology, Validation, Writing – review & editing. Wu Songsong: Conceptualization, Funding acquisition, Investigation, Methodology, Project administration, Resources, Supervision, Writing – original draft, Writing – review & editing.Liang Xia and Zeng Xiantao contributed equally to this work and are designated as co-first authors. References Clark DP (2009) Seize the opportunity: underutilization of fne-needle aspiration biopsy to inform targeted cancer therapy decisions. Cancer 117:289–297 Volpe A, Finelli A, Gill IS, et al. Rationale for percutaneous biopsy and histologic characterisation of renal tumours. Eur Urol. 2012; 62:491-504 Volpe A, Kachura JR, Geddie WR, et al. Techniques, safety and accuracy of sampling of renal tumors by fine needle aspiration and core biopsy. J Urol.2007;178:379-386 Smaldone MC, Corcoran AT, Uzzo RG. Active surveillance of small renal masses. Nat Rev Urol. 2013;10:266-274 Marconi L, Dabestani S, Lam TB et al (2016) Systematic review and meta-analysis of diagnostic accuracy of percutaneous renal tumour biopsy. Eur Urol 69:660–673 Weiss CR, Nour SG, Lewin JS (2008) MR-guided biopsy: a review of current techniques and applications. J Magn Reson Imaging 27:311–325 Veltri A, Garetto I, Tosetti I et al (2011) Diagnostic accuracy and clinical impact of imaging-guided needle biopsy of renal masses. Retrospective analysis on 150 cases. Eur Radiol 21:393–401 Richard PO, Jewett MA, Bhatt JR, et al. Renal tumor biopsy for small renal masses: a single-center 13-year experience. European Urology. 2015;68(6):1007–1013 Rouprêt M, Babjuk M, Burger M, et al. European Association of Urology Guidelines on Upper Urinary Tract Urothelial Carcinoma: 2020 Update. Eur Urol. 2021;79(1):62-79 Jinzaki M, Silverman SG, Akita H, et al. Renal angiomyolipoma: radiological classification and update on recent developments in diagnosis and management. Abdom Imaging. 2014 Jun;39(3):588-604 Elawdy MM, Osman Y, Taha DE, et al. Long-term outcomes of upper tract urothelial carcinoma: A retrospective evaluation of single-center experience in 275 patients. Turk J Urol. 2019 Feb 5;45(3):177-182 Sheth S, Ali S, Fishman EK. Imaging of Renal Lymphoma: Patterns of Disease with Pathologic Correlation. Radiographics. 2006;26(4):1151-1168 Michael Staehler, Severin Rodler, Isabel Brinkmann, et al. Long-Term Follow-Up in Patients Undergoing Renal Mass Biopsy: Seeding is not Anecdotal. Clin Genitourin Cancer. 2024 Apr;22(2):189-192 Caoili EM, Davenport MS (2014) Role of percutaneous needle biopsy for renal masses. Semin Intervent Radiol 31:20–26 Braak SJ, van Melick HHE, Onaca MG, van Heesewijk JPM, van Strijen MJL (2012) 3D cone-beam CT guidance, a novel technique in renal biopsy–results in 41 patients with suspected renal masses. Eur Radiol 22(11):2547–2552 Sanchez A, Feldman AS, Hakimi AA (2018) Current management of small renal masses, including patient selection, renal tumor biopsy, active surveillance, and thermal ablation. J Clin Oncol 36(36): 3591–3600 Kim MH (2017) CT-guided biopsy of entirely endophytic small renal masses: diagnostic rates and complications using standarddose and reduced-dose CT protocols. AJR Am J Roentgenol 208(5):1030–1036 Kutikov A, Uzzo RG (2009) The R.E.N.A.L. nephrometry score: a comprehensive standardized system for quantitating renal tumor size, location and depth. J Urol. 182(3):844–53 Clavien PA, Barkun J, de Oliveira ML et al (2009) The ClavienDindo classification of surgical complications: five-year experience. Ann Surg 250(2):187–196 Park SY, Park BK, Kim CK, Kwon GY (2013) Ultrasound-guided core biopsy of small renal masses: diagnostic rate and limitations. J Vasc Interv Radiol 24(1):90–96 Prince J, Bultman E, Hinshaw L et al (2015) Patient and tumor characteristics can predict nondiagnostic renal mass biopsy findings. J Urol 193(6):1899–1904 Patel HD, Johnson MH, Pierorazio PM et al (2016) Diagnostic accuracy and risks of biopsy in the diagnosis of a renal mass suspicious for localized renal cell carcinoma: systematic review of the literature. J Urol 195(5):1340–1347 Leveridge MJ, Finelli A, Kachura JR et al (2011) Outcomes of small renal mass needle core biopsy, nondiagnostic percutaneous biopsy, and the role of repeat biopsy. Eur Urol 60(3):578–584 Paterson C, Ghaemi J, Alashkham A et al (2018) Diagnostic accuracy of image-guided biopsies in small (<4 cm) renal masses with implications for active surveillance: a systematic review of the evidence. Br J Radiol 91(1090):20170761 Shannon BA, Cohen RJ, de Bruto H, Davies RJ (2008) The value of preoperative needle core biopsy for diagnosing benign lesions among small, incidentally detected renal masses. J Urol 180(4): 1257–1261 Posielski NM, Bui A, Wells SA et al (2019) Risk factors for complications and nondiagnostic results following 1,155 consecutive percutaneous core renal mass biopsies. J Urol 201(6):1080–1087 Seager MJ, Patel U, Anderson CJ, Gonsalves M (2018) Imageguided biopsy of small (≤4 cm) renal masses: the effect of size and anatomical location on biopsy success rate and complications. Br J Radiol 91(1085):20170666 Halverson SJ, Kunju LP, Bhalla R et al (2013) Accuracy of determining small renal mass management with risk stratified biopsies: confirmation by final pathology. J Urol 189(2):441–446 Wang R, Wolf JS, Wood DP, Higgins EJ, Hafez KS (2009) Accuracy of percutaneous core biopsy in management of small renal masses. Urology 73(3):586–590 Yang CS, Choi E, Idrees MT, et al. Percutaneous biopsy of the renal mass: FNA or core needle biopsy? Cancer Cytopathol . 2017;125(6):407-415 Rizzo M, Cabas P, Pavan N,, et al. Needle tract seeding after percutaneous cryoablation of small renal masses; a case series and literature review. Scand J Urol. 2020 Apr;54(2):122-127 Tomiyama N, Yasuhara Y, Nakajima Y, Adachi S, Arai Y, Kusumoto M, et al. CT-Guided Needle Biopsy of Lung Lesions: A Survey of Severe Complication Based on 9783 Biopsies in Japan. Eur J Radiol (2006) 59(1):60–4 Gupta S. Role of image-guided percutaneous needle biopsy in cancer staging. Semin Roentgenol . 2006;41(2):78-90 Additional Declarations No competing interests reported. Supplementary Files Supplementarymaterial.docx Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-6942528","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":483395035,"identity":"351b460c-550a-4c9b-96ed-f0fc14bb8c02","order_by":0,"name":"Liang Xia","email":"","orcid":"","institution":"Fujian Provincial Hospital, Affiliated Hospital of Fuzhou University","correspondingAuthor":false,"prefix":"","firstName":"Liang","middleName":"","lastName":"Xia","suffix":""},{"id":483395036,"identity":"da30272b-45d1-48be-9133-ceea7ad79158","order_by":1,"name":"Zeng Xiantao","email":"","orcid":"","institution":"Fujian Provincial Hospital, Affiliated Hospital of Fuzhou University","correspondingAuthor":false,"prefix":"","firstName":"Zeng","middleName":"","lastName":"Xiantao","suffix":""},{"id":483395037,"identity":"e924e3b2-5dec-405c-a454-5eeef404a6aa","order_by":2,"name":"Su Miaojiao","email":"","orcid":"","institution":"Fujian Provincial Hospital, Affiliated Hospital of Fuzhou University","correspondingAuthor":false,"prefix":"","firstName":"Su","middleName":"","lastName":"Miaojiao","suffix":""},{"id":483395038,"identity":"13c907a3-5cb9-4fa5-b3d4-3a1d9fbd53d7","order_by":3,"name":"Hong Zhiliang","email":"","orcid":"","institution":"Fujian Provincial Hospital, Affiliated Hospital of Fuzhou University","correspondingAuthor":false,"prefix":"","firstName":"Hong","middleName":"","lastName":"Zhiliang","suffix":""},{"id":483395039,"identity":"1c79d8cf-d43e-4d5c-b279-9f525ad16e60","order_by":4,"name":"Wu Songsong","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA/ElEQVRIiWNgGAWjYHAD5gMHPv6x4eHnbyBaC1viw5kNaTKSMw4QrYXH2Ji34bCNQUMCfnUGN9IfPi74VSdnzr/ATIJ3x3keA4YDjB8+5uDTkmNsPLPvsLHljAdpEpJnbvOYMzcwS87chluL2Y0cNmnengOJG24cOCZhwHabx7LhABszL14t6c+AWuqAWg62SSSwneMxOJBASEuCmTTPD+bEDeebmQ0Oth0grMX+zBtwQBkb3GBjfNhwJplHcsbBZrx+kWwHhhjPnzo5g/PnPxz+U2Fnz8/ffPDDRzxawICxDUhIJMC5DQTUg8AfIOY/QITCUTAKRsEoGJEAAMZYWsHLS5zQAAAAAElFTkSuQmCC","orcid":"","institution":"Fujian Provincial Hospital, Affiliated Hospital of Fuzhou University","correspondingAuthor":true,"prefix":"","firstName":"Wu","middleName":"","lastName":"Songsong","suffix":""}],"badges":[],"createdAt":"2025-06-21 04:23:04","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-6942528/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-6942528/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":86642894,"identity":"ef45dad3-df1f-4c8e-bf40-23570a6c391f","added_by":"auto","created_at":"2025-07-14 08:33:49","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":319179,"visible":true,"origin":"","legend":"\u003cp\u003eThe dashed boxes in panels A and B indicate the renal sinus region.\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-6942528/v1/bb5137749ffd7350b3f326ff.png"},{"id":86642893,"identity":"0a548153-0610-481b-9684-106cba7ce098","added_by":"auto","created_at":"2025-07-14 08:33:49","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":54478,"visible":true,"origin":"","legend":"\u003cp\u003eFlowchart of patient selection.\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-6942528/v1/6718b23194e07fcca9f59d41.png"},{"id":86646243,"identity":"5718e361-aee7-487a-b950-50ffe297058b","added_by":"auto","created_at":"2025-07-14 08:57:49","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":248401,"visible":true,"origin":"","legend":"\u003cp\u003eSchematic diagram of the puncture procedure. During the procedure, a region with contrast enhancement and favorable accessibility on contrast-enhanced ultrasound should be selected to ensure the shortest and safest puncture path. After the needle enters the renal capsule, care should be taken to avoid arcuate arteries. The trajectory should also avoid the renal columns and the collecting system. Real-time color Doppler monitoring must be employed, and needle advancement should be stopped immediately if arterial signals are detected. The needle should then be angle-adjusted and advanced slowly and steadily at a speed of less than 2 mm/s to minimize the risk of tissue tearing.\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-6942528/v1/99f51f475cba060feb57cdcc.png"},{"id":86642899,"identity":"69dac9b8-d76b-47c7-b6ff-b0030d69836b","added_by":"auto","created_at":"2025-07-14 08:33:49","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":140382,"visible":true,"origin":"","legend":"\u003cp\u003eChanges in Treatment Strategies Following Biopsy\u003c/p\u003e","description":"","filename":"4.png","url":"https://assets-eu.researchsquare.com/files/rs-6942528/v1/0e0a030b1a28ddbf31836d65.png"},{"id":86642900,"identity":"feeda3ea-75bc-400f-8c5f-60eb0323517e","added_by":"auto","created_at":"2025-07-14 08:33:49","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":537984,"visible":true,"origin":"","legend":"\u003cp\u003eImaging findings and interventional diagnosis and treatment of a left renal mass in an 85-year-old male patient after right nephrectomy.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e(A)\u003c/strong\u003e Two-dimensional ultrasound (convex probe, 3.5 MHz) revealed an irregular hypoechoic mass (45 mm × 28 mm) in the left renal sinus with poorly defined margins, exhibiting infiltrative growth along the renal pelvis (arrow).\u003cbr\u003e\n \u003cstrong\u003e(B)\u003c/strong\u003e Color Doppler imaging (sampling box angled 30°, PRF 800 Hz) showed scattered punctate flow signals within the lesion, suggesting mild neovascularization.\u003cbr\u003e\n \u003cstrong\u003e(C)\u003c/strong\u003e Contrast-enhanced CT (arterial phase, slice thickness: 2 mm) demonstrated a hypovascular lesion in the renal pelvis with a “fast-in, slow-out” enhancement pattern, raising suspicion for renal pelvic carcinoma.\u003cbr\u003e\n \u003cstrong\u003e(D)\u003c/strong\u003e Contrast-enhanced ultrasound using SonoVue® (mechanical index 0.08) showed homogeneous, mildly hypoenhancing lesion with clear demarcation from the surrounding renal parenchyma.\u003cbr\u003e\n \u003cstrong\u003e(E)\u003c/strong\u003e Ultrasound-guided percutaneous biopsy of the left renal sinus was performed using an 18G semi-automatic core needle at a 22° angle. The needle trajectory and tip (triangle marker) were clearly visualized in real time. Pathological examination confirmed IgG4-related kidney disease.\u003cbr\u003e\n \u003cstrong\u003e(F)\u003c/strong\u003e Follow-up after one year of high-dose methylprednisolone therapy showed significant lesion shrinkage on ultrasound, with reduction in lesion size to 22 mm × 15 mm (a 62% decrease from baseline), supporting the efficacy of medical treatment.\u003c/p\u003e","description":"","filename":"5.png","url":"https://assets-eu.researchsquare.com/files/rs-6942528/v1/f73442cd94326966a16adf00.png"},{"id":91088352,"identity":"0eac273c-5951-44aa-82cc-d25f60161e86","added_by":"auto","created_at":"2025-09-11 12:39:09","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":2302994,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6942528/v1/9a54e67d-11de-420c-90cd-4404f9082650.pdf"},{"id":86642905,"identity":"be0dd6f0-eb20-452a-a12e-4ef453859433","added_by":"auto","created_at":"2025-07-14 08:33:49","extension":"docx","order_by":0,"title":"","display":"","copyAsset":false,"role":"supplement","size":2405230,"visible":true,"origin":"","legend":"","description":"","filename":"Supplementarymaterial.docx","url":"https://assets-eu.researchsquare.com/files/rs-6942528/v1/56314269e55df39cc90dcb37.docx"}],"financialInterests":"No competing interests reported.","formattedTitle":"Ultrasound-Guided Core Needle Biopsy for Renal Sinus Masses: A Valuable Tool in the Preoperative Evaluation of Urologic Tumors","fulltext":[{"header":"Introduction","content":"\u003cp\u003eImage-guided percutaneous biopsy plays a pivotal role in the management of oncology patients, contributing not only to initial diagnosis and tumor staging, but also to treatment monitoring, assessment of residual lesions, and confirmation of tumor recurrence\u003csup\u003e[\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]\u003c/sup\u003e. It also provides valuable information for patients with comorbidities who may not be suitable candidates for surgery. These patients may benefit from alternative therapeutic approaches such as active surveillance and thermal ablation. Moreover, with the advent of targeted biologic therapies\u0026mdash;particularly in the era of personalized and precision medicine\u0026mdash;obtaining high-quality tissue samples has become essential for molecular subtyping and biomarker testing\u003csup\u003e[\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e][\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e][\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]\u003c/sup\u003e. Among various guidance modalities, ultrasound (US) and computed tomography (CT) are the most widely used imaging techniques. Owing to its convenience, real-time visualization, and lack of ionizing radiation, ultrasound has become one of the preferred imaging guidance methods in clinical practice\u003csup\u003e[\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]\u003c/sup\u003e.\u003c/p\u003e\u003cp\u003eIn recent years, advances in technology have expanded the role of ultrasound guidance in biopsies of lesions located in anatomically complex regions. However, unlike renal parenchymal lesions, biopsies of the renal sinus are technically challenging due to its intricate anatomy and proximity to vital structures such as blood vessels and the ureter\u003csup\u003e[\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e][\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]\u003c/sup\u003e. Nevertheless, ultrasound-guided renal sinus biopsy offers promising diagnostic potential for both benign and malignant lesions, owing to its real-time visualization and precise targeting capabilities\u003csup\u003e[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]\u003c/sup\u003e.\u003c/p\u003e\u003cp\u003eA variety of benign and malignant tumors can arise in the renal sinus. Malignant tumors include transitional cell carcinoma (TCC) of the renal pelvis, sinus-invading renal cell carcinoma (RCC), lymphoma, and metastatic tumors\u003csup\u003e[\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]\u003c/sup\u003e. Benign lesions include angiomyolipoma (AML), perirenal cysts, and inflammatory pseudotumors\u003csup\u003e[\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]\u003c/sup\u003e. TCC of the renal pelvis is the most common malignancy of the renal sinus, accounting for over 90% of all upper urinary tract urothelial carcinomas. Its 5-year survival rate is largely influenced by the tumor stage\u003csup\u003e[\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]\u003c/sup\u003e. Lymphoma may also involve the renal sinus, presenting as either diffuse infiltration or a focal mass, and can be difficult to distinguish from other renal sinus lesions\u003csup\u003e[\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]\u003c/sup\u003e. The complex histological spectrum of renal sinus lesions and the heterogeneity of tumors present significant diagnostic challenges. In many cases, imaging alone is insufficient to reliably differentiate benign renal masses, indolent renal cell carcinomas, and aggressive subtypes\u003csup\u003e[\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]\u003c/sup\u003e. Accurate diagnosis is therefore critical for guiding appropriate treatment strategies.\u003c/p\u003e\u003cp\u003ePrevious studies have demonstrated that ultrasound-guided biopsy of renal masses has a high success rate in obtaining sufficient high-quality tissue samples, with a low complication rate\u003csup\u003e[\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e][\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e][\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e][\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]\u003c/sup\u003e. However, systematic studies on percutaneous biopsy of renal sinus masses remain scarce, particularly those integrating data on diagnostic accuracy and safety. This presents an opportunity for further investigation into the clinical significance of ultrasound-guided biopsy of renal sinus masses. At our institution, clinical preference has allowed us to perform a relatively large number of ultrasound-guided biopsies of renal sinus masses. This has enabled a comprehensive analysis of the diagnostic performance and safety profile of ultrasound-guided biopsy of renal sinus masses in a relatively large cohort. This study aims to retrospectively analyze ultrasound-guided core needle biopsy cases of renal sinus masses to assess the diagnostic efficacy, technical feasibility, and safety of the procedure, and to explore its impact on clinical management.\u003c/p\u003e"},{"header":"Materials and Methods","content":"\u003cp\u003e\u003cstrong\u003eEthical Statement\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis retrospective study was approved by the Institutional Review Board of Fujian Provincial Hospital, with permission granted for chart review and a waiver of written informed consent.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eStudy Population\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eUsing the ultrasound workstation (Lanwon, version: V7 Build1560312), we retrospectively identified patients who were referred to our ultrasound department between April 2010 and October 2020 for percutaneous ultrasound-guided core needle biopsy of renal sinus masses with indeterminate imaging features. A preliminary screening using the keywords \u0026quot;kidney\u0026quot; and \u0026quot;biopsy\u0026quot; identified a total of 133 patients.\u0026nbsp;Of these, 71 patients who underwent renal parenchymal biopsies (i.e., targeting the cortex or medulla) rather than renal sinus biopsies (i.e., targeting peripelvic fat, vessels, and lymphatics, which appear hyperechoic on renal ultrasound; see Figure 1) were excluded.\u003c/p\u003e\n\u003cp\u003eWe subsequently reviewed the electronic medical records of 62 patients who met the criteria for ultrasound-guided renal sinus core needle biopsy. Data collected included demographic information (age, sex); mass characteristics (size, location, solid or cystic-solid composition, RENAL score); procedural details (number of biopsy cores, total specimen length, use of needle tract ablation or embolization, and complications); pathological diagnosis (histopathology or surgical pathology); and subsequent clinical management (diagnostic yield, histological subtype, post-biopsy imaging follow-up for late complications or needle tract seeding, follow-up duration, need for repeat biopsy, and treatment outcomes).\u003c/p\u003e\n\u003cp\u003eFor patients who subsequently underwent surgical resection, the histological findings from the biopsy were compared with the final surgical pathology to determine diagnostic accuracy. Eleven patients were excluded due to incomplete clinical data (missing imaging or medical records), resulting in a final cohort of 51 eligible patients(Figure 2).\u003c/p\u003e\n\u003cp\u003eAll patients were evaluated by a multidisciplinary tumor board at our institution, comprising specialists in medical oncology, urology, diagnostic radiology, and interventional ultrasound. Patients were considered eligible for renal sinus biopsy if they met at least one of the following criteria: (1) clinical history and prior imaging studies (i.e., contrast-enhanced CT or magnetic resonance imaging [MRI]) suggested a renal sinus mass without a definitive benign or malignant diagnosis, or (2) histological confirmation was required to guide clinical treatment, such as targeted therapy.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEquipment\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003eUltrasound examinations were performed using Philips iU22 and GE Vivid 7 Dimension color Doppler systems, equipped with linear-array transducers (5\u0026ndash;12 MHz) and convex-array transducers (2\u0026ndash;5 MHz).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eUltrasound-Guided Renal Sinus Biopsy\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll patients underwent routine preoperative laboratory tests, including complete blood count, biochemical profile, and coagulation function assessment, as well as imaging evaluations with CT or MRI.\u0026nbsp;The interventional radiologist carefully reviewed preoperative imaging to assess the location of the renal sinus lesion and its relationship to adjacent structures. A pre-biopsy ultrasound scan was performed, with contrast-enhanced ultrasound (CEUS) used to identify solid components as biopsy targets.\u0026nbsp;The puncture site was then routinely disinfected and draped, followed by local infiltration anesthesia.\u0026nbsp;Under real-time in-plane ultrasound guidance, a 17G coaxial introducer needle (KIM-16; ITP, BARD Company, USA) was inserted into the target lesion.\u0026nbsp;Using an 18G semi-automatic biopsy needle (BIM-18; ITP), 1\u0026ndash;4 core specimens were obtained through the coaxial sheath(Figure 3).\u0026nbsp;If bleeding was observed during the biopsy, a small amount of thrombin was injected through the coaxial sheath to embolize the needle tract.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eNeedle Tract Ablation Procedure\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eSome patients underwent needle tract thermal ablation post-biopsy, with the procedure performed at the discretion of the operator based on perceived bleeding risk.\u0026nbsp;A bipolar radiofrequency (RF) ablation device was used as the biopsy needle during this procedure.\u0026nbsp;After selecting the puncture site, a 15G coaxial introducer needle was inserted to the lesion margin under in-plane ultrasound guidance.\u0026nbsp;After removal of the inner stylet, a 16G core-cutting biopsy needle (Zhejiang Curaway Medical Technology Inc., China) was loaded into an automatic biopsy gun to obtain tissue samples.\u0026nbsp;The inner core was then reinserted, and the RF generator was activated to deliver thermal ablation via the working electrode at the tip of the outer sheath. The needle was held in place until the target temperature was reached, then slowly withdrawn until fully removed from the kidney.\u003c/p\u003e\n\u003cp\u003eThe number of biopsy passes was determined subjectively by the operator based on the gross appearance of the specimens, with no on-site pathological evaluation.\u0026nbsp;All biopsy procedures were performed by two senior ultrasound-guided interventional physicians (W.S.S., 20 years of experience; Y.J.C., 15 years of experience).\u0026nbsp;All procedures were performed under local anesthesia.\u0026nbsp;After the procedure, manual compression was applied to the puncture site for 5 minutes, followed by sterile dressing. Patients were observed for 30\u0026ndash;60 minutes and underwent ultrasound to screen for post-procedural bleeding before discharge.\u0026nbsp;Patients remained on bed rest for 2 hours postoperatively without pharmacological intervention and were discharged the following day after overnight observation.\u003c/p\u003e\n\u003cp\u003eAll biopsy specimens were analyzed by a urogenital pathologist with 15 years of experience (W.C.), and were subsequently used to assess for post-procedural complications.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEvaluation Criteria\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe complexity of renal masses was assessed using the RENAL nephrometry score, based on the method proposed by Kutikov and Uzzo\u003csup\u003e[18]\u003c/sup\u003e; postoperative complications were graded according to the Clavien\u0026ndash;Dindo classification system\u003csup\u003e[19]\u003c/sup\u003e.\u003c/p\u003e\n\u003cp\u003ePathological evaluation: A diagnosis was considered successful if the pathology revealed malignancy, or if a benign diagnosis was confirmed by \u0026ge;12 months of stable imaging follow-up. Conversely, a diagnosis was deemed inaccurate if a lesion initially diagnosed as benign showed progression on follow-up imaging or was later found to contain malignant components on repeat biopsy or surgery.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eStatistical Analysis\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eStatistical analyses were performed using SPSS software, version 26.0 (IBM Corp., Armonk, NY, USA).\u0026nbsp;Categorical variables are presented as frequencies and percentages, while continuous variables are expressed as medians with ranges. The overall diagnostic success rate and complication rate of ultrasound-guided percutaneous biopsy of renal sinus masses were calculated.\u0026nbsp;To identify factors associated with diagnostic success and complications, univariate logistic regression using Firth\u0026rsquo;s penalized likelihood method was employed. Variables included maximum tumor diameter (\u0026gt;30 mm vs. \u0026le;30 mm), tumor location (upper/middle vs. lower pole), proximity to the renal hilum, number of punctures (1\u0026ndash;4), and whether tract ablation was performed (for complication analysis). Results were reported as odds ratios (ORs) with 95% confidence intervals (CIs). Statistical significance was defined as a two-sided \u003cem\u003ep\u003c/em\u003e-value of \u0026lt;0.05.\u003c/p\u003e"},{"header":"Results","content":"\u003cp\u003e\u003cstrong\u003ePatient and Tumor Characteristics\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eA total of 51 patients who underwent ultrasound-guided percutaneous core needle biopsy of renal sinus masses were included in the study. Of these, 29 were male (56.86%) and 22 were female (43.14%). The median age was 63 years (range: 19\u0026ndash;85 years). The median maximum tumor diameter was 37 mm (range: 13\u0026ndash;106 mm). Heterogeneous enhancement was observed in 56.86% of lesions (29/51). According to the RENAL nephrometry scoring system, 88.23% of lesions (45/51) were classified as highly complex (scores of 10\u0026ndash;12), and 11.77% were moderately complex (scores of 7\u0026ndash;9); no low-complexity tumors were identified. Baseline patient characteristics are summarized in Table 1.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eDiagnostic Performance and Histopathological Findings\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eIn this study, the overall diagnostic success rate of ultrasound-guided percutaneous biopsy of renal sinus masses was 90.20% (46/51); 5 cases (9.80%) yielded non-diagnostic results due to insufficient tissue or necrosis. In two cases, the initial biopsy yielded only one tissue core, which was insufficient for diagnosis; both were later confirmed by surgery to be urothelial carcinoma of the renal pelvis. One lesion exhibited extensive central necrosis with no viable area on CEUS, and was confirmed postoperatively as clear cell renal cell carcinoma (Fuhrman grade III). In one case, severe fibrosis in the biopsy specimen precluded diagnosis; laparoscopic biopsy later confirmed a solitary fibrous tumor. One case was complicated by intraoperative bleeding that interfered with sampling; a second CT-guided biopsy confirmed metastatic adenocarcinoma originating from the lung. Univariate logistic regression analysis showed no significant associations between diagnostic success and tumor size (\u0026gt;30 mm vs. \u0026le;30 mm), tumor location (upper/middle vs. lower pole), proximity to the renal hilum, or number of biopsy passes (1\u0026ndash;4) (Table 3). Details of all 51 cases are summarized in Table 2.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eComplication Analysis\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe overall complication rate of ultrasound-guided percutaneous biopsy of renal sinus masses was 7.84% (4/51), including three cases of perirenal hematoma (15\u0026ndash;20 mm in diameter) and one case of gross hematuria, all classified as Clavien\u0026ndash;Dindo grade I\u0026ndash;II. Details of management and outcomes are as follows:\u003cbr\u003e\u003cstrong\u003eCase 1\u003c/strong\u003e: Immediate postoperative ultrasound revealed a 15 mm hematoma. The patient remained hemodynamically stable and was managed with local compression and extended bed rest (6 hours). The hematoma resolved spontaneously within one week, as confirmed on follow-up ultrasound.\u003cbr\u003e\u003cstrong\u003eCase 2\u003c/strong\u003e: Minor bleeding occurred during the procedure. Thrombin (500 IU) was injected via the coaxial sheath to embolize the needle tract. The patient was observed for 24 hours postoperatively without the need for further intervention.\u003cbr\u003e\u003cstrong\u003eCase 3\u003c/strong\u003e: The patient developed mild flank pain 24 hours post-procedure. Ultrasound confirmed a 20 mm perirenal hematoma. Symptomatic treatment with analgesia and an extended hospital stay (48 hours) was provided. The hematoma resolved completely by one-month follow-up.\u003cbr\u003e\u003cstrong\u003eCase 4 (hematuria)\u003c/strong\u003e: Gross hematuria developed 6 hours after biopsy. The patient was treated with intravenous tranexamic acid and absolute bed rest. Hematuria resolved within 24 hours without evidence of coagulopathy or thrombotic events.\u003c/p\u003e\n\u003cp\u003eNo major complications such as arteriovenous fistula, significant hemorrhage, or nephrectomy were observed. Univariate logistic regression analysis showed no significant associations between complication occurrence and tumor size (\u0026gt;30 mm vs. \u0026le;30 mm), tumor location (upper/middle vs. lower pole), proximity to the renal hilum, number of biopsy passes (1\u0026ndash;4), or needle tract ablation (Table 4).\u003c/p\u003e\n\u003cp\u003eAll available post-biopsy axial imaging data were retrospectively reviewed to evaluate for delayed complications and needle tract seeding. As of the time of data collection, five patients had no imaging or clinical follow-up. Among the remaining 46 patients, the median imaging follow-up period was 5 years (range: 0.2\u0026ndash;12 years). No imaging findings suggestive of delayed complications or tumor seeding along the biopsy tract were identified.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eImpact on Clinical Decision-Making\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eBiopsy results altered the treatment strategy in 23.5% (12/51) of patients, including 7.8% (4/51) in whom unnecessary surgery was avoided(Figure 5、Suppl. Fig. 1). Among the 46 patients with available treatment data, 29 underwent surgery alone\u0026mdash;25 underwent radical nephrectomy and 4 underwent partial nephrectomy(Suppl. Fig. 2、Suppl. Fig. 3、Suppl. Fig. 4). Three patients received ablation therapy, two received chemotherapy, and two were managed with active surveillance. Ten patients underwent combination therapy, including chemotherapy plus surgery in seven cases and chemotherapy plus radiotherapy in three (Figure 4).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 1\u0026nbsp;\u003c/strong\u003ePatient and Tumor Characteristics\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"542\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 291px;\"\u003e\n \u003cp\u003e\u003cstrong\u003ePatients Characteristic\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 125px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eN=51\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 125px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u003cem\u003e\u0026nbsp;\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 291px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 125px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eN\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 125px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e%\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 291px;\"\u003e\n \u003cp\u003eAge (years)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 125px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 125px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 291px;\"\u003e\n \u003cp\u003eMedian\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 125px;\"\u003e\n \u003cp\u003e63\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 125px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 291px;\"\u003e\n \u003cp\u003eRange (mean)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 125px;\"\u003e\n \u003cp\u003e19-85（64.29）\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 125px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 291px;\"\u003e\n \u003cp\u003eGender\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 125px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 125px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 291px;\"\u003e\n \u003cp\u003eFemale\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 125px;\"\u003e\n \u003cp\u003e22\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 125px;\"\u003e\n \u003cp\u003e43.14\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 291px;\"\u003e\n \u003cp\u003eMale\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 125px;\"\u003e\n \u003cp\u003e29\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 125px;\"\u003e\n \u003cp\u003e56.86\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 291px;\"\u003e\n \u003cp\u003eMaximum Diameter\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 125px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 125px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 291px;\"\u003e\n \u003cp\u003eMedian\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 125px;\"\u003e\n \u003cp\u003e31\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 125px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 291px;\"\u003e\n \u003cp\u003eRange (mean)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 125px;\"\u003e\n \u003cp\u003e13-78（30.09）\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 125px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 291px;\"\u003e\n \u003cp\u003eLaterality\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 125px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 125px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 291px;\"\u003e\n \u003cp\u003eLeft\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 125px;\"\u003e\n \u003cp\u003e27\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 125px;\"\u003e\n \u003cp\u003e52.94\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 291px;\"\u003e\n \u003cp\u003eRight\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 125px;\"\u003e\n \u003cp\u003e24\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 125px;\"\u003e\n \u003cp\u003e47.06\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 291px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eEnhancement Pattern\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 125px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 125px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 291px;\"\u003e\n \u003cp\u003eHomogeneous\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 125px;\"\u003e\n \u003cp\u003e22\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 125px;\"\u003e\n \u003cp\u003e43.14\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 291px;\"\u003e\n \u003cp\u003eHeterogeneous\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 125px;\"\u003e\n \u003cp\u003e29\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 125px;\"\u003e\n \u003cp\u003e56.86\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 291px;\"\u003e\n \u003cp\u003eRENAL nephrometry score\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 125px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 125px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 291px;\"\u003e\n \u003cp\u003eLow（4-6）\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 125px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 125px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 291px;\"\u003e\n \u003cp\u003eModerate（7-9）\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 125px;\"\u003e\n \u003cp\u003e6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 125px;\"\u003e\n \u003cp\u003e11.76\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 291px;\"\u003e\n \u003cp\u003eHigh（10-12）\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 125px;\"\u003e\n \u003cp\u003e45\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 125px;\"\u003e\n \u003cp\u003e88.24\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003cstrong\u003eTable 2\u0026nbsp;\u003c/strong\u003ePathological Results\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"536\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 291px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eDiagnostic\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eN\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 142px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e%\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 291px;\"\u003e\n \u003cp\u003eBenign\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 142px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 291px;\"\u003e\n \u003cp\u003e\u0026nbsp; Angiomyolipoma\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 142px;\"\u003e\n \u003cp\u003e3.92\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 291px;\"\u003e\n \u003cp\u003eEosinophilic Adenoma\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 142px;\"\u003e\n \u003cp\u003e3.92\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 291px;\"\u003e\n \u003cp\u003eSolitary Fibrous Tumor\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 142px;\"\u003e\n \u003cp\u003e1.96\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 291px;\"\u003e\n \u003cp\u003eIgG4-related Kidney Disease\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 142px;\"\u003e\n \u003cp\u003e1.96\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 291px;\"\u003e\n \u003cp\u003eMalignant\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 142px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 291px;\"\u003e\n \u003cp\u003e\u0026nbsp; Transitional Cell Carcinoma (TCC)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e22\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 142px;\"\u003e\n \u003cp\u003e43.14\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 291px;\"\u003e\n \u003cp\u003e\u0026nbsp; RCC, clear cell\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e16\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 142px;\"\u003e\n \u003cp\u003e31.37\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 291px;\"\u003e\n \u003cp\u003e\u0026nbsp; RCC, papillary\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 142px;\"\u003e\n \u003cp\u003e3.92\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 291px;\"\u003e\n \u003cp\u003e\u0026nbsp; RCC, chromophobe\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 142px;\"\u003e\n \u003cp\u003e1.96\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 291px;\"\u003e\n \u003cp\u003e\u0026nbsp; Metastatic\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 142px;\"\u003e\n \u003cp\u003e5.88\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 291px;\"\u003e\n \u003cp\u003e\u0026nbsp; Lymphoma\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 142px;\"\u003e\n \u003cp\u003e1.96\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003cstrong\u003eTable 3\u0026nbsp;\u003c/strong\u003eUnivariate Logistic Regression Model for Diagnostic Success Rate\u0026nbsp;\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"539\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 132px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eParameter level\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 189px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eSuccessful Diagnoses / Total\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eOR\u003c/strong\u003e\u003cstrong\u003e（\u003c/strong\u003e\u003cstrong\u003eCI\u003c/strong\u003e\u003cstrong\u003e）\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 85px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u003cem\u003eP\u003c/em\u003e\u003c/strong\u003e\u003cstrong\u003e-value\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003eMaximum diameter\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 189px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 85px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026le;30 mm\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 189px;\"\u003e\n \u003cp\u003e4/33\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003e\u0026mdash;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 85px;\"\u003e\n \u003cp\u003e\u0026mdash;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026gt;30 mm\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 189px;\"\u003e\n \u003cp\u003e1/18\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003e0.43(0.04\u0026ndash;4.12)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 85px;\"\u003e\n \u003cp\u003e0.64\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003eLocation\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 189px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 85px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp; \u0026nbsp;Upper\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 189px;\"\u003e\n \u003cp\u003e2/7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003e\u0026mdash;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 85px;\"\u003e\n \u003cp\u003e\u0026mdash;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003e\u0026nbsp; Mid\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 189px;\"\u003e\n \u003cp\u003e3/32\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003e0.26(0.03 - 1.95)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 85px;\"\u003e\n \u003cp\u003e0.25\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003eLower\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 189px;\"\u003e\n \u003cp\u003e0/12\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003e0.08 (0.00 - 1.97)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 85px;\"\u003e\n \u003cp\u003e0.20\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003eNearness to hilum\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 189px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 85px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003e\u0026nbsp; Not near\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 189px;\"\u003e\n \u003cp\u003e2/31\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003e\u0026mdash;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 85px;\"\u003e\n \u003cp\u003e\u0026mdash;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003eNear\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 189px;\"\u003e\n \u003cp\u003e3/20\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003e2.56（0.39 - 16.78）\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 85px;\"\u003e\n \u003cp\u003e0.34\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003eBiopsy cores (N)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 189px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 85px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003e\u0026nbsp; 1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 189px;\"\u003e\n \u003cp\u003e2/6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003e\u0026mdash;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 85px;\"\u003e\n \u003cp\u003e\u0026mdash;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003e\u0026nbsp; 2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 189px;\"\u003e\n \u003cp\u003e3/19\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003e0.38 (0.01 - 0.50)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 85px;\"\u003e\n \u003cp\u003e0.19\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003e\u0026nbsp; 3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 189px;\"\u003e\n \u003cp\u003e0/17\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003e0.05 (0.00 - 1.19)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 85px;\"\u003e\n \u003cp\u003e0.10\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003e4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 189px;\"\u003e\n \u003cp\u003e0/9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003e0.09 (0.00 - 2.29)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 85px;\"\u003e\n \u003cp\u003e0.27\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003cstrong\u003eTable 4\u0026nbsp;\u003c/strong\u003eUnivariate Logistic Regression Model for Complications\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"539\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 142px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eParameter level\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 151px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eComplications / Total\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 161px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eOR\u003c/strong\u003e\u003cstrong\u003e（\u003c/strong\u003e\u003cstrong\u003eCI\u003c/strong\u003e\u003cstrong\u003e）\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 85px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u003cem\u003eP\u003c/em\u003e\u003c/strong\u003e\u003cstrong\u003e-value\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 142px;\"\u003e\n \u003cp\u003eMaximum diameter\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 151px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 161px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 85px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 142px;\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026le;30 mm\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 151px;\"\u003e\n \u003cp\u003e2/33\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 161px;\"\u003e\n \u003cp\u003e\u0026mdash;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 85px;\"\u003e\n \u003cp\u003e\u0026mdash;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 142px;\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026gt;30 mm\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 151px;\"\u003e\n \u003cp\u003e2/18\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 161px;\"\u003e\n \u003cp\u003e1.94 (0.25\u0026ndash;15.07)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 85px;\"\u003e\n \u003cp\u003e0.61\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 142px;\"\u003e\n \u003cp\u003eLocation\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 151px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 161px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 85px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 142px;\"\u003e\n \u003cp\u003e\u0026nbsp; Upper\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 151px;\"\u003e\n \u003cp\u003e1/12\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 161px;\"\u003e\n \u003cp\u003e\u0026mdash;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 85px;\"\u003e\n \u003cp\u003e\u0026mdash;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 142px;\"\u003e\n \u003cp\u003e\u0026nbsp; Mid\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 151px;\"\u003e\n \u003cp\u003e3/32\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 161px;\"\u003e\n \u003cp\u003e1.14 (0.13 - 10.18)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 85px;\"\u003e\n \u003cp\u003e0.56\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 142px;\"\u003e\n \u003cp\u003eLower\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 151px;\"\u003e\n \u003cp\u003e0/7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 161px;\"\u003e\n \u003cp\u003e0.54 (0.02 - 6.23)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 85px;\"\u003e\n \u003cp\u003e1.00\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 142px;\"\u003e\n \u003cp\u003eNearness to hilum\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 151px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 161px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 85px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 142px;\"\u003e\n \u003cp\u003e\u0026nbsp; Not near\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 151px;\"\u003e\n \u003cp\u003e2/31\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 161px;\"\u003e\n \u003cp\u003e\u0026mdash;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 85px;\"\u003e\n \u003cp\u003e\u0026mdash;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 142px;\"\u003e\n \u003cp\u003eNear\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 151px;\"\u003e\n \u003cp\u003e2/20\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 161px;\"\u003e\n \u003cp\u003e0.33（0.02, 3.52）\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 85px;\"\u003e\n \u003cp\u003e0.42\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 142px;\"\u003e\n \u003cp\u003eBiopsy cores (N)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 151px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 161px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 85px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 142px;\"\u003e\n \u003cp\u003e\u0026nbsp; 1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 151px;\"\u003e\n \u003cp\u003e1/6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 161px;\"\u003e\n \u003cp\u003e\u0026mdash;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 85px;\"\u003e\n \u003cp\u003e\u0026mdash;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 142px;\"\u003e\n \u003cp\u003e\u0026nbsp; 2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 151px;\"\u003e\n \u003cp\u003e2/19\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 161px;\"\u003e\n \u003cp\u003e0.59 (0.04 - 5.15)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 85px;\"\u003e\n \u003cp\u003e0.63\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 142px;\"\u003e\n \u003cp\u003e\u0026nbsp; 3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 151px;\"\u003e\n \u003cp\u003e0/17\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 161px;\"\u003e\n \u003cp\u003e0.10 (0.00 - 3.07)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 85px;\"\u003e\n \u003cp\u003e0.32\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 142px;\"\u003e\n \u003cp\u003e4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 151px;\"\u003e\n \u003cp\u003e1/9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 161px;\"\u003e\n \u003cp\u003e0.63(0.03 - 6.82)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 85px;\"\u003e\n \u003cp\u003e1.00\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 142px;\"\u003e\n \u003cp\u003eTract ablation\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 151px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 161px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 85px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 142px;\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp; Yes\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 151px;\"\u003e\n \u003cp\u003e4/35\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 161px;\"\u003e\n \u003cp\u003e\u0026mdash;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 85px;\"\u003e\n \u003cp\u003e\u0026mdash;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 142px;\"\u003e\n \u003cp\u003eNo\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 151px;\"\u003e\n \u003cp\u003e0/16\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 161px;\"\u003e\n \u003cp\u003e0.22(0.03 - 3.74)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 85px;\"\u003e\n \u003cp\u003e0.30\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eOur retrospective analysis of 51 cases undergoing ultrasound-guided percutaneous renal sinus core needle biopsy demonstrated that this technique offers high diagnostic efficacy and favorable safety in patients with highly complex renal masses. The overall diagnostic yield was 90.20%, with malignant lesions accounting for 88.24% and benign lesions for 11.76%. Moreover, the overall complication rate was only 5.88%, all of which were minor, with no major complications observed. Compared with previous literature, our findings further support the value of ultrasound-guided renal sinus biopsy in achieving accurate diagnosis and informing therapeutic decision-making.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eDiagnostic Performance and Histopathological Correlation\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eImage-guided percutaneous renal parenchymal biopsy has been extensively reported, with diagnostic accuracy ranging from 85.5% to 97.1%, and major/minor complication rates reported at 0\u0026ndash;0.9% and 1.8\u0026ndash;20.3%, respectively\u003csup\u003e[20]\u003c/sup\u003e\u003csup\u003e[21]\u003c/sup\u003e\u003csup\u003e[22]\u003c/sup\u003e\u003csup\u003e[23]\u003c/sup\u003e\u003csup\u003e[24]\u003c/sup\u003e\u003csup\u003e[25]\u003c/sup\u003e\u003csup\u003e[26]\u003c/sup\u003e\u003csup\u003e[27]\u003c/sup\u003e\u003csup\u003e[28]\u003c/sup\u003e\u003csup\u003e[29]\u003c/sup\u003e.\u0026nbsp;Furthermore, Yang et al\u003csup\u003e[30]\u003c/sup\u003e. compared the efficacy of fine-needle aspiration (FNA) and core needle biopsy, and found that core biopsy had a significantly higher diagnostic yield (88% vs. 72%, \u003cem\u003ep\u003c/em\u003e \u0026lt; 0.01). However, studies focusing on renal sinus biopsy remain limited. Although MRI guidance is widely regarded as suitable for biopsies of deep or anatomically complex regions due to its superior soft-tissue contrast, our findings demonstrate that ultrasound-guided biopsy of the renal sinus achieves a comparable diagnostic accuracy (90.2%) to MRI-guided biopsy (90\u0026ndash;96%). The exclusive use of core needle biopsies in our cohort may partially explain the high diagnostic rate. This result may be attributed to the advantages of real-time ultrasound imaging, which enables multiplanar observation and contrast-enhanced targeting. In particular, for hypervascular renal sinus lesions\u0026mdash;56.86% of tumors in this study exhibited heterogeneous enhancement\u0026mdash;CEUS facilitates precise localization of viable tissue, thereby avoiding necrotic or cystic regions and improving sampling accuracy. Moreover, US guidance circumvents the high cost and operational complexity of MRI systems, making it more suitable for resource-limited clinical settings. Univariate logistic regression analysis revealed no significant association between biopsy success and tumor size (\u0026gt;30 mm vs. \u0026le;30 mm, OR = 0.43, 95% CI: 0.04\u0026ndash;4.12, \u003cem\u003ep\u003c/em\u003e = 0.64), location (upper/mid vs. lower pole), proximity to the renal hilum, or the number of biopsy passes (1\u0026ndash;4). The five biopsy failures (9.80%) were attributed to limited specimen volume, intratumoral necrosis, and fibrosis. Notably, 88.24% of tumors in our study were classified as highly complex (RENAL score 10\u0026ndash;12), and 56.86% demonstrated heterogeneous enhancement. Despite this, a high diagnostic rate was maintained, suggesting that ultrasound guidance is a technically reliable approach even in complex renal sinus lesions.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eSafety and Complication Analysis\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe overall complication rate in this study was 7.84%, all of which were classified as minor (Clavien-Dindo grade I\u0026ndash;II), including perirenal hematoma and gross hematuria. No severe complications requiring additional intervention or needle tract seeding were observed, consistent with previous reports of ultrasound-guided percutaneous renal biopsy (3%\u0026ndash;10%). Although the renal sinus is anatomically complex, being adjacent to the renal hilum vessels and ureter, all hematomas were small (\u0026le;20 mm) and resolved completely with local compression, thrombin sealing of the needle tract, or hemostatic medication, suggesting a manageable risk profile for puncture in this area.\u003c/p\u003e\n\u003cp\u003eFormation of perirenal hematoma may be attributed to minor vascular injury along the puncture path; however, the real-time dynamic imaging capability of ultrasound allows for adjustment of the needle trajectory to avoid major vascular branches, thereby limiting hematoma expansion. Gross hematuria may result from minor injury to the collecting system or renal pelvic mucosa. In this study, all cases were effectively resolved within 24 hours with intravenous tranexamic acid and strict bed rest. The prompt resolution of these complications underscores the potential advantage of ultrasound guidance in minimizing severe bleeding. It is worth noting that the renal sinus has been infrequently selected as a biopsy route in clinical practice, primarily due to its proximity to vital vascular structures and the potential risk of tumor seeding along the needle tract\u003csup\u003e[31]\u003c/sup\u003e. Literature reports indicate a needle tract seeding rate of 0.01% to 6% following renal biopsy\u003csup\u003e[13]\u003c/sup\u003e. Some cases are identified during routine pathological evaluation after nephrectomy, while in patients without surgical treatment, the true incidence may be underestimated due to delayed clinical presentation or pre-mortem unmanifested progression\u003csup\u003e[32]\u003c/sup\u003e. Repeated sampling using the same needle in a single patient may inadvertently implant microscopic tumor cells.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eConsequently, renal sinus biopsy has not been widely recommended in international guidelines, and its safety remains a subject of ongoing concern. Nevertheless, univariate analysis in this study revealed no significant association between complication rates and tumor size, number of needle passes, or needle tract ablation. Operator experience (e.g., precise selection of avascular paths) and standardized protocols (e.g., coaxial needle systems, immediate post-procedural tract ablation) may be key factors in reducing the risk of perirenal hematoma and hematuria. In addition, to prevent tumor seeding, all procedures in this study employed coaxial needle systems with immediate tract ablation. Follow-up imaging revealed no evidence of tract seeding or delayed complications. This may have contributed to the absence of such complications in our cohort. Although the follow-up period was limited, further studies with larger samples and extended observation are needed to assess the long-term risk of seeding.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eImpact on Clinical Decision-Making\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eRenal biopsy not only serves diagnostic purposes but also directly informs treatment decisions. In our study, biopsy results led to a change in the therapeutic strategy for 23.53% of patients. Notably, four patients (7.84%) were spared unnecessary surgery due to a confirmed benign diagnosis, underscoring the role of ultrasound-guided biopsy in personalized treatment planning.\u003c/p\u003e\n\u003cp\u003eWith the increasing use of targeted and immunotherapies in recent years, pathological confirmation has become crucial for selecting optimal treatment strategies. In our cohort, urothelial carcinoma of the renal pelvis accounted for 43.14% of all malignant cases\u0026mdash;substantially differing in management from renal cell carcinoma. While the former typically requires chemotherapy and ureterectomy, the latter may be managed with partial nephrectomy as a first-line option. These findings support the assertion by Gupta et al\u003csup\u003e[33]\u003c/sup\u003e. that image-guided biopsy should be an integral component of renal tumor management.\u003c/p\u003e\n\u003cp\u003eIn 88.23% of malignant cases, accurate histological subtyping\u0026mdash;primarily urothelial carcinoma (43.14%) and clear cell renal cell carcinoma (31.37%)\u0026mdash;provided crucial guidance for targeted therapy selection and surgical planning. Our results demonstrate that ultrasound-guided percutaneous renal sinus biopsy offers essential information for individualized therapy, helping to avoid overtreatment and optimize patient outcomes. In cases of renal sinus lesions with inconclusive imaging findings, suspected metastases requiring molecular subtyping for targeted therapy, or indeterminate lesions under active surveillance, biopsy confirmation is critical. Ultrasound-guided biopsy serves as a preferred diagnostic tool, particularly for patients with multiple comorbidities or elevated surgical risk.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eStudy Limitations\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis study has several limitations. First, as a single-center retrospective analysis, the relatively small sample size may limit the statistical power, and the inclusion of cases from a single institution\u0026mdash;based on imaging uncertainty prior to biopsy\u0026mdash;could introduce selection bias, potentially leading to an overestimation of the diagnostic yield. Second, the loss to follow-up in five patients may have compromised the completeness of delayed complication assessment. Additionally, the relatively short follow-up period in some cases precluded a comprehensive evaluation of the long-term safety of the procedure, including the potential risk of needle tract seeding.\u003c/p\u003e\n\u003cp\u003eNot all cases were confirmed by surgical pathology (only 39 patients underwent surgery), which may have resulted in an overestimation of diagnostic accuracy. Furthermore, the influence of operator experience on procedural outcomes was not assessed. This study also did not include a direct comparison with CT- or MRI-guided renal biopsy, which limits conclusions regarding the relative diagnostic performance of different imaging modalities.\u003c/p\u003e\n\u003cp\u003eFuture prospective, multicenter studies are warranted to validate these findings. In addition, integrating ultrasound elastography or artificial intelligence-assisted localization may help improve the visualization and targeting of deep-seated lesions. Although no needle tract seeding was observed during a median follow-up of five years in this study, longer-term data are needed to fully assess the risk of rare complications.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eUltrasound-guided percutaneous core needle biopsy of renal sinus masses is a safe, efficient, and cost-effective technique that provides critical diagnostic information for complex renal sinus lesions and supports informed clinical decision-making. Despite anatomical challenges and potential sample heterogeneity, its advantages\u0026mdash;particularly the absence of radiation exposure and real-time dynamic imaging\u0026mdash;underscore its important role in renal tumor management. With continued technological innovation and multidisciplinary collaboration, this approach holds promise for further optimizing clinical decision-making pathways in the management of renal tumors.\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003cp\u003e\u003cstrong\u003eUS\u003c/strong\u003e：ultrasound\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCT\u003c/strong\u003e：computed tomography\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMRI\u003c/strong\u003e：magnetic resonance imaging\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCEUS\u003c/strong\u003e：contrast-enhanced ultrasound\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCI\u003c/strong\u003e：confidence interval\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eOR\u003c/strong\u003e：odds ratio\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eRF\u003c/strong\u003e：radiofrequency\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTCC\u003c/strong\u003e：transitional\u0026nbsp;cell\u0026nbsp;carcinoma\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eRCC\u003c/strong\u003e：renal cell carcinoma\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAML\u003c/strong\u003e：angiomyolipoma\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eFunding\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe author(s) declare that financial support was received for the research, authorship, and/or publication of this article. Fujian Science and Technology Innovation Joint Fund project climbing project (2023Y9332).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConflict of interest\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgments\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors are thankful to Fujian Provincial Hospital and Fujian Medical University for their management of our patient database.\u003c/p\u003e\n\u003cp\u003eThe authors are thankful to Song-Song Wu for helping critically revise the manuscript for important intellectual content and helping collect data and design the study.\u003c/p\u003e\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eLiang Xia: Conceptualization, Data curation, Formal Analysis, Investigation, Methodology, Software, Validation, Visualization, Writing \u0026ndash; original draft, Writing \u0026ndash; review \u0026amp; editing. Zeng Xiantao: Conceptualization, Data curation, Investigation, Writing \u0026ndash; review \u0026amp; editing. Su Miaojiao: Conceptualization, Data curation, Methodology, Writing \u0026ndash; review \u0026amp; editing. Hong Zhiliang: Methodology, Validation, Writing \u0026ndash; review \u0026amp; editing. Wu Songsong: Conceptualization, Funding acquisition, Investigation, Methodology, Project administration, Resources, Supervision, Writing \u0026ndash; original draft, Writing \u0026ndash; review \u0026amp; editing.Liang Xia and Zeng Xiantao contributed equally to this work and are designated as co-first authors.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eClark DP (2009) Seize the opportunity: underutilization of fne-needle aspiration biopsy to inform targeted cancer therapy decisions. Cancer 117:289\u0026ndash;297\u003c/li\u003e\n\u003cli\u003eVolpe A, Finelli A, Gill IS, et al. Rationale for percutaneous biopsy and histologic characterisation of renal tumours. Eur Urol. 2012; 62:491-504\u003c/li\u003e\n\u003cli\u003eVolpe A, Kachura JR, Geddie WR, et al. Techniques, safety and accuracy of sampling of renal tumors by fine needle aspiration and core biopsy. J Urol.2007;178:379-386\u003c/li\u003e\n\u003cli\u003eSmaldone MC, Corcoran AT, Uzzo RG. Active surveillance of small renal masses. Nat Rev Urol. 2013;10:266-274\u003c/li\u003e\n\u003cli\u003eMarconi L, Dabestani S, Lam TB et al (2016) Systematic review and meta-analysis of diagnostic accuracy of percutaneous renal tumour biopsy. Eur Urol 69:660\u0026ndash;673\u003c/li\u003e\n\u003cli\u003eWeiss CR, Nour SG, Lewin JS (2008) MR-guided biopsy: a review of current techniques and applications. J Magn Reson Imaging 27:311\u0026ndash;325\u003c/li\u003e\n\u003cli\u003eVeltri A, Garetto I, Tosetti I et al (2011) Diagnostic accuracy and clinical impact of imaging-guided needle biopsy of renal masses. Retrospective analysis on 150 cases. Eur Radiol 21:393\u0026ndash;401\u003c/li\u003e\n\u003cli\u003eRichard PO, Jewett MA, Bhatt JR, et al. Renal tumor biopsy for small renal masses: a single-center 13-year experience. European Urology. 2015;68(6):1007\u0026ndash;1013\u003c/li\u003e\n\u003cli\u003eRoupr\u0026ecirc;t M, Babjuk M, Burger M, et al. European Association of Urology Guidelines on Upper Urinary Tract Urothelial Carcinoma: 2020 Update. \u003cem\u003eEur Urol.\u003c/em\u003e 2021;79(1):62-79\u003c/li\u003e\n\u003cli\u003eJinzaki M, Silverman SG, Akita H, et al. Renal angiomyolipoma: radiological classification and update on recent developments in diagnosis and management. Abdom Imaging. 2014 Jun;39(3):588-604\u003c/li\u003e\n\u003cli\u003eElawdy MM, Osman Y, Taha DE, et al. Long-term outcomes of upper tract urothelial carcinoma: A retrospective evaluation of single-center experience in 275 patients. Turk J Urol. 2019 Feb 5;45(3):177-182\u003c/li\u003e\n\u003cli\u003eSheth S, Ali S, Fishman EK. Imaging of Renal Lymphoma: Patterns of Disease with Pathologic Correlation. \u003cem\u003eRadiographics.\u003c/em\u003e 2006;26(4):1151-1168\u003c/li\u003e\n\u003cli\u003eMichael Staehler, Severin Rodler, Isabel Brinkmann, et al. Long-Term Follow-Up in Patients Undergoing Renal Mass Biopsy: Seeding is not Anecdotal. Clin Genitourin Cancer. 2024 Apr;22(2):189-192\u003c/li\u003e\n\u003cli\u003eCaoili EM, Davenport MS (2014) Role of percutaneous needle biopsy for renal masses. Semin Intervent Radiol 31:20\u0026ndash;26\u003c/li\u003e\n\u003cli\u003eBraak SJ, van Melick HHE, Onaca MG, van Heesewijk JPM, van Strijen MJL (2012) 3D cone-beam CT guidance, a novel technique in renal biopsy\u0026ndash;results in 41 patients with suspected renal masses. Eur Radiol 22(11):2547\u0026ndash;2552 \u003c/li\u003e\n\u003cli\u003eSanchez A, Feldman AS, Hakimi AA (2018) Current management of small renal masses, including patient selection, renal tumor biopsy, active surveillance, and thermal ablation. J Clin Oncol 36(36): 3591\u0026ndash;3600 \u003c/li\u003e\n\u003cli\u003eKim MH (2017) CT-guided biopsy of entirely endophytic small renal masses: diagnostic rates and complications using standarddose and reduced-dose CT protocols. AJR Am J Roentgenol 208(5):1030\u0026ndash;1036\u003c/li\u003e\n\u003cli\u003eKutikov A, Uzzo RG (2009) The R.E.N.A.L. nephrometry score: a comprehensive standardized system for quantitating renal tumor size, location and depth. J Urol. 182(3):844\u0026ndash;53\u003c/li\u003e\n\u003cli\u003eClavien PA, Barkun J, de Oliveira ML et al (2009) The ClavienDindo classification of surgical complications: five-year experience. Ann Surg 250(2):187\u0026ndash;196\u003c/li\u003e\n\u003cli\u003ePark SY, Park BK, Kim CK, Kwon GY (2013) Ultrasound-guided core biopsy of small renal masses: diagnostic rate and limitations. J Vasc Interv Radiol 24(1):90\u0026ndash;96\u003c/li\u003e\n\u003cli\u003ePrince J, Bultman E, Hinshaw L et al (2015) Patient and tumor characteristics can predict nondiagnostic renal mass biopsy findings. J Urol 193(6):1899\u0026ndash;1904\u003c/li\u003e\n\u003cli\u003ePatel HD, Johnson MH, Pierorazio PM et al (2016) Diagnostic accuracy and risks of biopsy in the diagnosis of a renal mass suspicious for localized renal cell carcinoma: systematic review of the literature. J Urol 195(5):1340\u0026ndash;1347\u003c/li\u003e\n\u003cli\u003eLeveridge MJ, Finelli A, Kachura JR et al (2011) Outcomes of small renal mass needle core biopsy, nondiagnostic percutaneous biopsy, and the role of repeat biopsy. Eur Urol 60(3):578\u0026ndash;584\u003c/li\u003e\n\u003cli\u003ePaterson C, Ghaemi J, Alashkham A et al (2018) Diagnostic accuracy of image-guided biopsies in small (\u0026lt;4 cm) renal masses with implications for active surveillance: a systematic review of the evidence. Br J Radiol 91(1090):20170761\u003c/li\u003e\n\u003cli\u003eShannon BA, Cohen RJ, de Bruto H, Davies RJ (2008) The value of preoperative needle core biopsy for diagnosing benign lesions among small, incidentally detected renal masses. J Urol 180(4): 1257\u0026ndash;1261\u003c/li\u003e\n\u003cli\u003ePosielski NM, Bui A, Wells SA et al (2019) Risk factors for complications and nondiagnostic results following 1,155 consecutive percutaneous core renal mass biopsies. J Urol 201(6):1080\u0026ndash;1087\u003c/li\u003e\n\u003cli\u003eSeager MJ, Patel U, Anderson CJ, Gonsalves M (2018) Imageguided biopsy of small (\u0026le;4 cm) renal masses: the effect of size and anatomical location on biopsy success rate and complications. Br J Radiol 91(1085):20170666\u003c/li\u003e\n\u003cli\u003eHalverson SJ, Kunju LP, Bhalla R et al (2013) Accuracy of determining small renal mass management with risk stratified biopsies: confirmation by final pathology. J Urol 189(2):441\u0026ndash;446\u003c/li\u003e\n\u003cli\u003eWang R, Wolf JS, Wood DP, Higgins EJ, Hafez KS (2009) Accuracy of percutaneous core biopsy in management of small renal masses. Urology 73(3):586\u0026ndash;590\u003c/li\u003e\n\u003cli\u003eYang CS, Choi E, Idrees MT, et al. Percutaneous biopsy of the renal mass: FNA or core needle biopsy? \u003cem\u003eCancer Cytopathol\u003c/em\u003e. 2017;125(6):407-415\u003c/li\u003e\n\u003cli\u003eRizzo M, Cabas P, Pavan N,, et al. Needle tract seeding after percutaneous cryoablation of small renal masses; a case series and literature review. Scand J Urol. 2020 Apr;54(2):122-127\u003c/li\u003e\n\u003cli\u003eTomiyama N, Yasuhara Y, Nakajima Y, Adachi S, Arai Y, Kusumoto M, et al. CT-Guided Needle Biopsy of Lung Lesions: A Survey of Severe Complication Based on 9783 Biopsies in Japan. Eur J Radiol (2006) 59(1):60\u0026ndash;4\u003c/li\u003e\n\u003cli\u003eGupta S. Role of image-guided percutaneous needle biopsy in cancer staging. \u003cem\u003eSemin Roentgenol\u003c/em\u003e. 2006;41(2):78-90\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Ultrasound-guided biopsy, renal sinus mass, diagnostic accuracy, complication rate, urothelial carcinoma, individualized treatment, image-guided intervention","lastPublishedDoi":"10.21203/rs.3.rs-6942528/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-6942528/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003eBackground\u003c/strong\u003e The renal sinus's complex anatomy challenges imaging diagnosis. Ultrasound-guided biopsy shows promise for renal sinus masses due to its real-time, radiation-free, and cost-effective advantages, but its efficacy and safety need validation.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eObjective\u003c/strong\u003e To evaluate the diagnostic performance, safety, and clinical impact of ultrasound-guided percutaneous core needle biopsy for renal sinus masses.\u003c/p\u003e\n\u003cp\u003eMaterials and Methods A retrospective analysis was conducted on 51 patients who underwent ultrasound-guided renal sinus biopsy at a tertiary medical center between April 2010 and October 2020. Inclusion criteria were renal sinus masses with indeterminate imaging features. Diagnostic yield, complications (graded by the Clavien–Dindo classification), and treatment plan modifications were recorded. Univariate logistic regression analysis was used to identify factors associated with complications.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eResults\u003c/strong\u003e The overall diagnostic yield was 90.2% (46/51), with malignant lesions accounting for 88.2% (45/51), including urothelial carcinoma of the renal pelvis (43.1%, 22/51) and clear cell renal cell carcinoma (31.4%, 16/51). Benign lesions accounted for 11.8% (6/51). The complication rate was 7.8% (4/51), including perirenal hematoma and gross hematuria (Clavien–Dindo grade I–II), with no cases of needle tract seeding or severe complications. Biopsy results altered treatment plans in 23.5% (12/51) of patients, and unnecessary surgery was avoided in 7.8% (4/51). Tumor size, location, number of needle passes, and tract ablation were not significantly associated with complications (all p \u0026gt; 0.05).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusion\u003c/strong\u003e Ultrasound-guided percutaneous biopsy of renal sinus lesions demonstrates high diagnostic efficacy (90.2%) and safety (complication rate: 7.8%) in complex renal sinus diseases. It enables precise clinical decision-making and helps avoid overtreatment. Its advantages of real-time imaging and absence of radiation make it a valuable tool in the management of renal tumors.\u003c/p\u003e","manuscriptTitle":"Ultrasound-Guided Core Needle Biopsy for Renal Sinus Masses: A Valuable Tool in the Preoperative Evaluation of Urologic Tumors","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-07-14 08:33:44","doi":"10.21203/rs.3.rs-6942528/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"4a1ee151-94c3-49b1-ae4d-c3a63cbb6ab5","owner":[],"postedDate":"July 14th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2025-09-11T12:38:39+00:00","versionOfRecord":[],"versionCreatedAt":"2025-07-14 08:33:44","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-6942528","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-6942528","identity":"rs-6942528","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}