Accounts for less than 1% of all urothelial neoplasms.
Usually composed of anastomosing islands and trabeculae of normal urothelial cells invaginating from the surface of the urothelium into subjacent lamina propria.
Does not invade into the muscularis propia.
Usually noted in men in the 6-7th decades.
Male:female ration 7.3:1.
Mean age 60 years.
89% in the urinary bladder with the trigone and bladder neck most frequently involved.
Patients present with hematuria, dysuria or irritative symptoms.
Incidence of multiple lesions about 1.3-44%.
An endophytic growth covered by an intact layer of normal urothelium.
Transurethral resection standard treatment.