UNRELIABILITY OF THE ABDOMINAL FAT PAD BIOPSY IN THE EVALUATION OF NEPHROSIS - REPORT OF 3 CONSECUTIVE CASES

In the workup of unexplained nephrotic syndrome in the elderly patient , renal biopsy has shown amyloidosis to be the cause in 15-30% of the cases. Most of the cases of amyloidosis are primary and are, therefore , treatable with alkylating agents, albeit at a high level of toxicity . Ab dominal fad pad biopsy has been suggested as a minimally invasive , low-cost method for diagnosing amyloidosis that is 100% specific. We report our experience with 3 consecutive cases of fat pad biopsy in t he workup of unexplained nephrosis in the elderly patient: including t he first false positive reported with respect to nephrotic renal disea se, a false negative, and a true positive. We feel that in an elderly patient with unexplained nephrosis though the abdominal fat pad biopsy may be helpful, the patient should not be committed to a regimen with potentially very high toxicity on the basis of a positive fat pad bio psy alone. We recommend that the more invasive renal biopsy be perform ed should therapy with alkylating agents be contemplated.