Xanthogranulomatous Pyelonephritis Mimicking a Complex Renal Cyst: A Report of a Rare Case.

Xanthogranulomatous pyelonephritis (XGPN) is a chronic granulomatous inflammatory condition that affects the kidney and can often be hard to diagnose preoperatively due to its varying clinical presentations. We present here a rare case of a 36-year-old man with focal XGPN with preoperative CT imaging showing a large heterogenous lesion (computer tomography Hounsfield unit (CT HU) + 20) of size ~ 8.6 x 8.9 x 9.4 cm (anteroposterior (AP) x transverse (TR) x craniocaudal (CC)) arising from the inter pole region with few hyperdense solid components and septations suggestive of a complex renal cyst. The patient underwent open decortication and excision of the infected complex right renal cyst with right DJ stenting. He was treated with antibiotics and had an uneventful post-operative period.