Abstract：
Xanthogranulomatous pyelonephritis (XPN) is an uncommon variant of chronic pyelonephritis with a poorly understood pathogenesis and a challenging diagnosis. It is rare in pediatric patients, particularly in the neonatal period. We report the case of an 18-day-old female neonate admitted to the emergency room due to macroscopic hematuria and poor feeding. Urinalysis revealed leukocyturia and she was initially admitted under the clinical suspicion of acute pyelonephritis. Renal ultrasound and magnetic resonance imaging (MRI) revealed a progressive nodular lesion in the middle third of the left kidney. Given the suspicion of renal abscess or neoplasm, the patient was transferred to our tertiary hospital. Urinary catecholamines and tumor markers had normal values. Percutaneous kidney biopsy confirmed XPN. Posterior computed tomography scan excluded extension to neighboring structures. A conservative management with systemic antibiotic therapy was decided. She completed 7 weeks of systemic antibiotic therapy (ampicillin and cefotaxime) with progressive reduction of lesion size and posterior calcification. Follow-up at 3 years was uneventful. The lipid profile and study of neutrophil function were normal. Voiding cystourethrography excluded vesicoureteral reflux. The authors intend to highlight the importance of a high index of suspicion of XPN to allow preoperative diagnosis. Histopathological assessment is mandatory to confirm XPN and exclude other entities mimicked by focal and unilateral progressive disease. There are only a few published cases of optimal clinical evolution solely with broad-spectrum antibiotics; however, this may allow a beneficial nephron-sparing approach in selected patients.
摘要：
黄色肉芽肿性肾盂肾炎（XPN）是慢性肾盂肾炎的罕见变种，其发病机制知之甚少，诊断具有挑战性。在儿科患者中很少见，尤其是在新生儿期。我们报告了一名18天大的女性新生儿因肉眼血尿和喂养不良而入院急诊室的病例。尿液分析显示白细胞增多，最初因临床怀疑为急性肾盂肾炎而入院。肾脏超声和磁共振成像（MRI）显示左肾中部三分之一的进行性结节性病变。鉴于怀疑肾脓肿或肿瘤，病人被转移到我们的三级医院。尿儿茶酚胺和肿瘤标志物具有正常值。经皮肾活检证实XPN。后路计算机断层扫描排除了对相邻结构的扩展。决定采用全身抗生素治疗的保守管理。她完成了7周的全身性抗生素治疗（氨苄西林和头孢噻肟），并逐渐减少了病变大小和后部钙化。3年的随访顺利。血脂和中性粒细胞功能研究正常。排尿膀胱尿道造影排除膀胱输尿管反流。作者打算强调高度怀疑XPN的重要性，以便进行术前诊断。必须进行组织病理学评估以确认XPN并排除其他被局灶性和单侧进行性疾病模仿的实体。只有少数已发表的仅使用广谱抗生素的最佳临床进化案例；然而，这可能允许在选定的患者中采用有益的保留肾单位的方法.
