A case of xanthogranulomatous pyelonephritis in a child.

We report an additional case of histopathologically confirmed xanthogranulomatous pyelonephritis in a 9-year-old boy. He was admitted to hospital with a two-day history of sustained fever. Physical examination revealed tenderness in the right upper quadrant of the abdomen. Results of a complete blood count and serum biochemical investigations showed slight anemia and positive C reactive protein. Culture of urine failed to grow any bacteria. Excretory urography revealed deformity of the right renal calyces. Computed tomography showed a focal area of low density in the right kidney. Nephrectomy was carried out as fever had been sustained despite intensive treatment with antibiotics. Sectioning revealed that the renal parenchyma had been replaced by a butter yellow nodule, which was histopathologically confirmed as xanthogranulomatous pyelonephritis. This is the nineteenth reported case in children in Japan to our knowledge.