A Wolf in Sheep’s Clothing: Xanthogranulomatous Pyelonephritis Mimicking Infection Revealing Underlying Renal Squamous Cell Carcinoma

Abstract

Renal masses associated with chronic infection may pose significant diagnostic challenges. We report a 59-year-old man presenting with abdominal pain and a palpable left abdominal mass. Initial ultrasound suggested severe hydronephrosis with proximal ureteral stone and a solid intrarenal lesion. Contrast-enhanced CT findings were consistent with Xanthogranulomatous Pyelonephritis. The patient subsequently underwent nephrectomy. Histopathological examination unexpectedly revealed Renal Squamous Cell Carcinoma. This case highlights the importance of considering underlying malignancy in chronic inflammatory renal conditions and emphasizes the role of imaging and histopathology in establishing definitive diagnosis.