Xanthogranulomatous pyelonephritis in nonfunctioning transplanted kidney.

Xanthogranulomatous pyelonephritis in native and allografted kidneys is a rare variant of severe chronic infection of the renal parenchyma. In a native kidney the diagnosis may sometimes be established by ultrasonography and computed tomography. In the renal allograft, the diagnosis could only be established by histologic evaluation of the transplant biopsy or nephrectomy. The reported case presents a febrile patient with a failing renal graft, in whom xanthogranulomatous pyelonephritis was established by histologic evaluation of transplantectomy specimens. Xanthogranulomatous pyelonephritis should therefore be included in the list of possible etiologies of the fever in patient with nonfunctioning transplanted kidney.