The etiopathogenesis of xanthogranulomatous pyelonephritis. With reference to two cases

Xanthogranulomatous pyelonephritis (XGP) is an uncommon inflammatory disease of the kidney whose diagnosis is histological. Nephrectomy and antimicrobial therapy are usually required. Two cases that may provide lessons for the as yet poorly understood etiopathogenesis of XGP are reported. These patients were a man and a woman, both aged 56 years, with a negative history for diabetes mellitus and urinary tract disease. The diagnosis was made upon examination of a left nephrectomy specimen. The pre- and intraoperative diagnosis in the woman was renal cancer. The man had undergone resection of an aneurysm of the abdominal aorta seven months earlier; during the procedure, the blood vessels to the left kidney had been manipulated. The left kidney was atrophic and surrounded by a collection of aseptic purulent fluid; xanthogranulomatous modifications were seen upon histology. In both patients, gammaglobulin levels were increased during the episode of XGP and returned to normal following nephrectomy. Conclusion: these two cases support the possibility that XGP may be a systemic disease (Papo Th., Piette J.C., Kahn), In the second patient, the onset after manipulation of the blood vessels to the kidney is additional evidence for the vascular pathogenetic theory.