Serendipitous diagnosis of childhood xanthogranulomatous pyelonephritis in a child with osteomyelitis.

Xanthogranulomatous pyelonephritis (XGP), a rare chronic renal infection in children, usually presents as high fever, pyuria and an abdominal mass. This child with clinical and radiologic evidence of osteomyelitis was not suspected of renal disease until a non-functioning kidney was discovered during a bone scan. The pathologic proven diagnosis of XGP could have been made by correlative imaging using renal ultrasound, a renal scan and a gallium scan. Computed tomography and voiding cystourethrography provided additional information as to the nature and extent of the disease process.