Experience of Ultrasonography-Guided Percutaneous Core Biopsy for Renal Masses

PURPOSE: We evaluated the safety and accuracy of ultrasonography-guided percutaneous core biopsy collection in patients with renal masses. MATERIALS AND METHODS: From June 2008 to August 2012, 30 percutaneous core biopsies of renal masses were performed. The biopsies obtained were small tumors (<4 cm) with ambiguous radiologic findings or that met classic renal biopsy indications. The biopsy results were compared with the final pathological results after definitive surgical treatment. Ultrasonography was performed on the day after biopsy collection to rule out any complications. RESULTS: The mean age of the patients was 57.7 years, and the mean tumor size was 3.39 cm. Twelve of the lesions were in the left kidney, and 18 were in the right kidney. All but one core biopsy contained sufficient material for histopathological analysis. The biopsy results showed 17 renal cell carcinomas (56.7%), 3 angiomyolipomas (10.0%), 2 oncocytomas (6.7%), 1 adenocarcinoma (3.3%), and 7 benign lesions (23.3%). A total of 18 cases underwent surgery, and the pathological results confirmed the initial biopsy diagnosis for 17 of 18 cases (94.4%). The one (5.9%) inaccurate biopsy result was found to be a urothelial carcinoma of the kidney. No needle tract seeding was found in the pathological specimens or on follow-up imaging. A small perinephric hematoma (1-2 cm) was seen in 5 cases (16.7%), but all patients remained hemodynamically stable. CONCLUSIONS: Ultrasonography-guided renal biopsy is a safe, effective, and accurate method for evaluating small renal masses. This procedure may help in selecting treatment modalities for small renal masses.