Villous Adenoma in Renal Pelvis With Manifestation of Percutaneous Fistula and Mucus Secretion.

A 70-year-old man, complaining of percutaneous fistula with jelly-like yellow mucus in the right kidney for a month, was admitted to our department. From computed tomography, stones and severe hydronephrosis but no suspicious mass was found in right kidney. Nephrectomy of right kidney was performed and pathological examination revealed a villous adenoma in the renal pelvis with moderate to severe atypical hyperplasia of glandular epithelium. Primary villous adenoma in renal pelvis is rare and believed to be related to chronic irritation of stone and inflammation. Mostly nephrectomy was performed before diagnosis was made.