Figure 1b: Biopsy of solid 3.5-cm right interpolar renal mass in a 68-year-old woman referred for percutaneous ablation. (a) Percutaneous biopsy of the mass (arrowhead) with 25-gauge needle (arrow), shown on transverse CT image, yielded inadequate cellular material. (b) CT-guided biopsy, shown on transverse CT image, was repeated with 18-gauge needle (arrow). (c) Photomicrograph shows cells were immunoreactive (arrows) for renal cell carcinoma antibody. (Original magnification, x600.) (d) Photomicrograph of cell block section reveals clear cell renal cell carcinoma. (Hematoxylin-eosin stain; original magnification, x400.)