Pure Villous Adenoma of the Vesicoureteric Junction Presenting as Pyonephrosis

Villous adenomas of the urinary tract are uncommon neoplasms which share similar morphological features with gastrointestinal villous adenomas. Only two case series and around 20 scattered case reports of villous adenoma in the urinary tract have been published in English literature till date. They have been identified mainly in the urinary bladder, urethra, prostate and urachus, but the occurrence of villous adenomas at the vesicoureteric junction has not been described. We present a case of villous adenoma of the vesicoureteric junction which completely occluded the lumen and led to gross pyonephrosis.