Ultrasound-Guided Percutaneous Core Biopsy of Renal Sinus Masses: Diagnostic Yield, Safety, and Clinical Impact

Background Renal sinus lesions present diagnostic challenges due to their complex anatomy and heterogeneous pathology. Reliable tissue acquisition is essential for guiding treatment decisions, yet evidence on the performance of ultrasound (US)-guided biopsy in this setting remains limited. Objective We retrospectively analyzed 51 patients who underwent US-guided percutaneous core needle biopsy of renal sinus masses at a tertiary medical center (2010–2020). Inclusion criteria were renal sinus masses with indeterminate imaging features. Diagnostic yield, histological results, complication rates (Clavien–Dindo classification), and subsequent treatment modifications were assessed. Univariate logistic regression was performed to explore factors associated with complications. Results Biopsy achieved a diagnostic yield of 90.2% (46/51). Malignant lesions accounted for 88.2% of cases, most commonly upper-tract urothelial carcinoma of the renal pelvis (43.1%) and clear cell renal cell carcinoma (31.4%). Benign lesions comprised 11.8%. The overall complication rate was 7.8% (4/51), limited to grade I–II events (perirenal hematoma, hematuria); no major complications or needle tract seeding were observed. Biopsy findings altered treatment in 23.5% of patients, and unnecessary surgery was avoided in 7.8%. Tumor size, location, and number of needle passes were not significantly associated with complications (all P  > 0.05). Conclusion US-guided percutaneous core biopsy of renal sinus masses is a safe and effective diagnostic approach, providing high tissue yield with low morbidity. By enabling accurate diagnosis and reducing overtreatment, this technique represents a valuable tool in the management of complex renal tumors.