What are the indications for renal biopsy, and what is the best way to biopsy the kidney?
Renal biopsy is a safe technique used to establish a diagnosis of focal renal lesions not characterized by diagnostic imaging or to assess nonfocal renal disease (nephropathy) or renal transplant rejection. With a high positive predictive value of renal biopsy for the diagnosis of renal cell carcinoma, malignancy can be confirmed prior to percutaneous ablation, when surgical removal is not anticipated.
Complicated cystic lesions can also be safely biopsied to differentiate benign renal cysts from cystic renal cell carcinoma. Nonfocal renal biopsies can be used to diagnose a wide spectrum of nephropathies affecting native kidneys and renal transplants.
The kidney is biopsied percutaneously under US or CT guidance, with some operators preferring US guidance for nonfocal renal disease and CT for biopsy of focal renal masses. Renal transplants are most often biopsied by US, given their superficial location in the pelvis. Generally, core biopsy samples are obtained.