Small Renal Mass Biopsy: When to Do?

The incidence of small renal mass (SRM) is increasing largely owing to the growing use of cross-sectional imaging. About 20% of SRMs are benign, and smaller masses are likely to have pathological characteristics of low malignant potential. Determining the optimal management for SRM can be challenging. Advances in our understanding of the nature of SRMs and expanding treatment options for SRMs have stimulated interest in SRM biopsy which can facilitate risk stratification and prognostication. Continuing concern regarding complications and accuracy, SRM biopsy is underutilized. However, recent series on SRM biopsy have reported diagnostic accuracy and rare complications. The median concordance rate between tumor histotype on renal tumor biopsy and on the surgical specimen was over 90%. SRM biopsy can be selectively used to improve risk stratification in patient where the clinical management may change on the basis of the results of biopsy. Currently, SRM biopsy can be recommended in most cases except in patients who have imaging or clinical characteristics indicative of benign tumors and in cases in which conservative management is considered. Urologists should be aware of the benefits of SRM biopsy which should be discussed with patients.