Small Renal Neoplasms

Radiologists frequently encounter small renal masses in daily practice. Most are small benign cysts which are difficult to characterize because of their size. With modern cross-sectional imaging techniques, however, it is possible to distinguish most of these from true renal neoplasms. The small renal neoplasms that contain fat or reside within the collecting system of the kidney are easily identified and managed appropriately. The remainder of enhancing, small solid renal masses continue to be a challenge. Since their histologic make-up and biologic behavior cannot be accurately predicted by imaging, a choice of nephron-sparing surgical or percutaneous ablation techniques vs “watchful waiting” are rational options for management. The appropriate course of action depends heavily on individual patient factors.