ReviewThe role of biopsy for small renal masses

- Small renal masses (SRMs) are defined as enhancing kidney tumours ≤4 cm that are usually incidentally detected. Most, but not all, are RCCs..
- SRMs are usually treated as presumed RCC. As a result, benign tumours and low grade RCCs of uncertain biology are being treated in over 20% of cases.
- Pretreatment renal tumour biopsy (RTB) can reduce potentially unnecessary treatment, but is not widely practiced yet.
- RTB is safe, with only a 1% incidence of significant complications, has a high diagnostic yield and accuracy, and is cost effective.
- RTB, together with molecular and genetic studies will improve our knowledge of SRMs and has the potential of risk-adapted personalized treatment

The incidence of small renal masses (SRMs) has been increasing due to the more liberal use of abdominal imaging. This increased detection has driven the attention of clinicians to the characterization of these lesions and toward a better understanding of their natural history. To this end, renal tumour biopsies (RTBs) have a crucial role as they provide vital pathological information. The improved quality and accuracy of RTBs provide urologists with a very truthful tool to support and guide treatment decisions. The future of RTB will combine pathological, molecular and genetic information that will, improve our knowledge about these lesions and open the potential for risk-adapted personalized medicine.