Management of small renal tumors with radiofrequency ablation

Imaging of RF ablation. (A) Contrast-enhanced computed tomography scan through lower pole of left kidney revealing a 5-cm enhancing mass anteriorly before RF ablation and (B) a somewhat larger, nonenhancing mass of nonviable tissue 1 month after RF ablation.

Macroscopic RF ablation. RF electrodes were inserted percutaneously into a human kidney under laparoscopic guidance. An ERBE RF surgical generator (120 W RF, 475 kHz) in the power control mode was used and 2 mL/min of 14.6% NaCl solution was infused through an 18-gauge insulated needle with a 1-cm exposed distal tip. The scheduled nephrectomy after RF ablation was performed, and (A) gross lesions are visible on tumor tissue (arrow). The kidney was then fixed in formalin, and the tissues were sectioned and subjected to hematoxylin-eosin histologic examination. (B) Microscopic hematoxylin-eosin staining for RF-treated normal renal tissue. (C) Acute effects of RF ablation on human renal tumors with distinct demarcation between zones of nonablated (dark arrows) and RF-ablated tumor tissue (light arrows).