[CLINICAL ANALYSIS ABOUT PERCUTANEOUS NEEDLE BIOPSY FOR RENAL MASSES]

(Objective) We investigated the efficacy and safety of percutaneous renal mass biopsy retrospectively. (Methods) A retrospective review was performed of 44 patients (46 renal masses) who received ultrasound and/or computed tomography guided percutaneous biopsy of a solid renal mass between April 2004 and December 2012 in National Defense Medical College Hospital. (Results) The median renal mass size was 45 (range 15-140) mm with a median of 2 (1-5) cores taken. Thirteen masses were biopsied for differential diagnosis between RCC and other malignancies (or benign renal tumors), 11 were biopsied for differential diagnosis between RCC and renal pelvic urothelial carcinoma, 10 unresectable masses were biopsied to confirm the diagnosis pathologically before starting medication, and 12 small masses were biopsied before radio-frequency ablation. Of the initial 46 biopsies, 38 (82.6%) were diagnostic. The median lesion sizes in the diagnostic and nondiagnostic biopsy specimens were 45 (15-140) mm and 43 (17-128) mm. The median numbers of diagnostic and nondiagnostic cores were 2 (1-5) and 1.5 (1-4). These size and core number differences between the diagnostic and nondiagnostic biopsy specimens are not statistically significant. Of initial nondiagnostic 8 masses, 3 masses that were performed repeat biopsy resulted in determined diagnosis finally. There were mild postprocedural hematomas not requiring blood transfusion. There was no tumor dissemination after renal mass biopsy. (Conclusions) Percutaneous biopsy of renal masses is a safe procedure that provides diagnostic information.