Uric acid nephrolithias in the era of noncontrast computed tomography

We report 2 patients who presented with uric acid renal calculi. Both patients had previously been treated unsuccessfully for their stones with shock wave lithotripsy and were referred to our centre for percutaneous nephrolithomy. We were able to avoid surgery in both cases owing to the recognition of uric acid stone composition despite the calculi being visible on CT scout films.