Xanthogranulomatous Pyelonephritis Associated with Systemic Amyloidosis

Abstract

Xanthogranulomatous pyelonephritis is rarely associated with systemic amyloidosis. To the best of our knowledge, this association has been described in only nine cases, including the present report. Our first patient, a 76-year-old woman, presented with chronic renal failure and xanthogranulomatous pyelonephritis in the right kidney associated with amyloidosis in the same kidney and ipsilateral adrenal. She has been followed up for 44 months and continues to do well with stable renal function and mild proteinuria. Our second patient, a 54-year-old woman, had a 25-year history of recurrent Proteus mirabilis urinary tract infections. She developed anuric chronic renal failure, becoming dependent on dialysis, and xanthogranulomatous pyelonephritis in the left kidney associated with amyloidosis in the same kidney. She died at 8 days postsurgery. The combination of lesions has been described in childhood and in adults presenting with chronic renal failure or nephrotic syndrome. Clinical remission of amyloidosis develops in a majority of the patients after the removal of the renal lesion. From a pathologic point of view our cases underline the importance of careful histologic examination of removed kidneys, even in conditions characterized by extensive destruction of renal tissue. To prevent the association with amyloidosis we emphasize the importance of early diagnosis and treatment of xanthogranulomatous pyelonephritis.