Biopsy of Solid Renal Lesions

The old teaching was that a renal lesion that could not be characterized as either a benign cyst or angiomyolipoma should be surgically resected. This was based the fact that old histologic techniques had high false-negative rates and could not reliably differentiate low-grade renal cell carcinoma from benign oncocytoma. In addition, there was concern for tumor seeding along the biopsy track.

The positive predictive value of biopsy for the diagnosis of renal cell carcinoma is now in the range of 95% – 100%, thanks to new biopsy techniques and histological analyses. In addition, the risk of tumor seeing is now known to be very low. For these reasons, many renal lesions that would have previously been resected, are now biopsied.

Solid renal lesions smaller than about 3 cm are difficult to characterize by imaging; therefore, biopsy may obviate the need for treatment of benign lesions.

Solid renal lesions are also biopsied prior to percutaneous ablation to determine appropriate follow-up and treatment of malignant lesions, and to avoid over-treatment of benign lesions. Indeed, in a series of 27 patients referred for percutaneous ablation, almost 40% of solid renal masses turned out to be benign.

References

• Heilbrun ME, Zagoria RJ, Garvin AJ, Hall MC, Krehbiel K, Southwick A, Clark PE. CT-guided biopsy for the diagnosis of renal tumors before treatment with percutaneous ablation. AJR Am J Roentgenol. 2007 Jun;188(6):1500-5.
• Tuncali K, vanSonnenberg E, Shankar S, Mortele KJ, Cibas ES, Silverman SG. Evaluation of patients referred for percutaneous ablation of renal tumors: importance of a preprocedural diagnosis. AJR Am J Roentgenol. 2004 Sep;183(3):575-82.
• Uppot RN, Harisinghani MG, Gervais DA. Imaging-guided percutaneous renal biopsy: rationale and approach. AJR Am J Roentgenol. 2010 Jun;194(6):1443-9.