一位74岁的女性来我院就诊，主诉为厌食和体重减轻数月。计算机断层扫描 (CT) 显示右尿路结石、肾积水、多发性淋巴结肿大和右肾肿块。考虑到这些发现，她怀疑患有肾恶性肿瘤（肾癌或肾盂癌）并伴有多处淋巴结转移；因此，进行了肾切除术。病理诊断为黄色肉芽肿性肾盂肾炎（XGPN）。术后肾功能未见下降，术后3个月CT上多发淋巴结肿大也消失。判断为炎症引起的反应性肿胀。 XGPN 是一种病理状况，其特征是肾组织中肥大细胞和活化的巨噬细胞积聚；并且，由于尿路通过障碍导致反复肾盂肾炎，肾组织识别出黄色肉芽生长。在某些情况下，很难区分 XGPN 和肾脏恶性肿瘤。另外，淋巴结肿大可能是淋巴结转移，但也可能因炎症的影响而出现反应性肿大，当伴有淋巴结肿大时，鉴别就更加困难。我们报告的这一病例中，考虑到 XGPN 伴有多发性淋巴结肿大的报道很少，很难将 XGPN 与肾脏恶性肿瘤区分开来。

A 74-year-old woman presented to our hospital with the main complaint of anorexia and weight loss for several months. Computed tomography (CT) revealed right urinary stone, hydronephrosis, multiple lymphadenopathy, and a mass in the right kidney. Considering these findings, she was suspected to have renal malignancy (kidney or renal pelvis cancer) with multiple lymph node metastases; therefore, nephrectomy was performed. Her pathological diagnosis was xanthogranulomatous pyelonephritis (XGPN). There was no postoperative renal function decline, and multiple lymphadenopathy also disappeared on CT 3 months after surgery. It was judged to be reactive swelling due to inflammation. XGPN is a pathological condition characterized by accumulation of mast cells and activated macrophages in the renal tissue; and, the renal tissue recognizes yellowish granulation growth because of repeating pyelonephritis due to urinary tract passing impairment. In some cases, it is difficult to differentiate XGPN from renal malignancy. Moreover, lymphadenopathy may be lymph node metastasis but may also present reactive enlargement due to the effect of inflammation, making it even more difficult to differentiate when accompanied by lymphadenopathy. We report this case in which it was difficult to differentiate XGPN from renal malignancy considering the scarcity of reports of XGPN accompanied by multiple lymphadenopathy.