Percutaneous US-guided needle biopsies of solid renal masses.

Our objective was to examine the variables affecting diagnostic yield and complications in percutaneous ultrasonography-guided needle biopsies of solid renal masses. Percutaneous ultrasonography-guided needle biopsy of solid renal masses was performed in 172 patients with either large size (18G) cutting needles or small size (20G) aspiration needles. Retrospectively, 120 patients with diagnosis by percutaneous biopsy and follow-up data were included in this series. Age, gender, side, locations in kidneys, necrosis, calcification, maximum size, needle groups due to needle size and type (either 18G cutting needles or 20G aspiration needles), and needle pass were selected as variables. Their role was investigated in diagnostic yield. Two needle groups were divided and compared for diagnostic yield and safety. Also, change in treatment was evaluated. The mean maximum size of the masses was 8.8±4.9 cm. The only predictor affecting accuracy was side of kidney (p=0.002). Among patients, 15 (12.5%) and 105 (87.5%) had benign and malignant solid masses, respectively. Small and large needle groups did not differ in accuracy, 80.3% vs. 87.1% (p=1.000). Technical success was detected as 100%. No major complications neither tumor seeding was seen. Percutaneous ultrasonography-guided needle biopsy of solid renal masses is effective and safe method with large size cutting needles and small aspiration needles. Change in clinical management was significant at 63.3% rate. Diagnostic yield was low in left kidney relating to right kidney, 69.4 vs. 93.1, while upper lobe location did not lead to significant false result. Repeat biopsies can be taken under CT guidance after nondiagnostic diagnosis in solid tumors of left kidney. All the needles including large cutting type were found safe.