Simultaneous High-Grade Upper-Tract Urothelial Carcinoma and Xanthogranulomatous Pyelonephritis.

A 67-year-old female with a previous history of superficial urothelial carcinoma of the bladder, discharged from surveillance follow-up, presented to her general practitioner with nausea and unintentional weight loss. The patient had radiological findings of a poor nephrogram with significant perirenal inflammatory stranding and hydronephrosis secondary to conglomerate pelvic calcification. This was suggestive of xanthogranulomatous pyelonephritis (XGP) and possible malignant changes. The patient ultimately underwent a radical nephrectomy; subsequently, the specimen revealed high-grade T4 urothelial cell carcinoma with background XGP, with vascular invasion and positive margins, but no evidence of spread to regional lymph nodes. She was referred onwards to oncology for further treatment given her margin status and is undergoing an intense and prolonged course of surveillance follow-up. This is likely one of the first reported cases of advanced disease with such diagnostic difficulty and surgical complexity.