Vacuolization of tubules in gadolinium-associated acute renal failure. 
While gadolinium was initially thought to be a safe alternative to iodinated contrast agents for patients with chronic renal insufficiency, many reports of gadolinium-associated acute renal failure have now been recorded, particularly in patients with underlying renal insufficiency.  In addition, animal models have demonstrated tubule vacuolization with experimental gadolinium administration that is similar to vacuolization seen with other contrast agents.  We present a case of a patient with nephrotic-range proteinuria and chronic renal insufficiency, who developed acute renal failure following gadolinium administration undergoing furosemide stimulated diuresis.  This case is the first report of pathologic tubule vacuolization in gadolinium-associated nephropathy in a human kidney biopsy.  This case suggests a relationship between the pathogenesis of CIN with standard contrast media and CIN with gadolinium.  Research is needed to better understand the pathologic findings and pathogenesis of gadolinium-associated nephrotoxicity.