Villous Adenoma of the Urinary Bladder: A Brief Review of the Literature.

Villous adenoma is a rare neoplasm in the urinary tract. It usually occurs in patients older than 50 years with a male predominance. The affected patients typically present with hematuria, irritative voiding symptoms, and mucosuria. The malignant potential of this entity has not been established, but some of the case series studies on bladder villous adenoma do suggest a possible association with malignant tumors. Findings on ultrasonography, computed tomographic scanning, magnetic resonance imaging, or on cystoscopic examination are nonspecific. Therefore, villous adenoma of the bladder is primarily a histologic diagnosis. This review will highlight the current theories on its pathogenesis and discuss its main histologic and immunohistochemical features to aid the diagnosis.