Focal xanthogranulomatous pyelonephritis sans calculus- a unique case Scenario

Introduction Xanthogranulomatous pyelonephritis(XGPN) is a great imitator as it has a wide range of atypical presentations and is difficult to diagnose clinically.We report a rare case of focal XGPN without stone masquerading as a renal neoplasm.Case Report-A 60 year old diabetic lady presented to our outpatient clinic with a history of left sided loin pain and dysuria of 2 months duration. There was no history of hematuria or LUTS. Clinical examination was unremarkable but for pallor. Investigations showed hemoglobin as 8.2 g, ESR- 38mmHr renal function was normal. Urine culture showed 10x5klebsiella growth. Ultrasonogram showed a mixed echogenic complex cystic mass arising from lower pole of the left kidney. Contrast CT scan of kidney showed enhancing mixed, dense, multiseptated cystic mass from lower pole of the left kidney, normal collecting system with no stone. The right kidney was normal. The lesion was extending into perinephric tissues with enlarged hilar nodes. Renal vein and IVC appeared normal. With a provisional diagnosis of a renal neoplasm, this patient was planned for left radical nephrectomy. Preoperative chest X-ray and liver function test were normal. Intraoperatively the lower pole was found adherent to psoas muscle and left colon which was carefully separated. Radical nephrectomy was completed and hilar nodes were sampled. Post operatively the patient recovered well but for a wound infection that required secondary suturing. To our surprise, the histopathology was reported as focal lower pole XGPN