Unlike histological features, the clinical - endoscopic characteristics of NA are non-specific. Even if it is not definitely considered like a premalignant condition, NA has to be followed up frequently and long lasting, because of its high recurrence rate. The combination of Cytology, Flow cytometry, DNA image analysis and Fluorescence in situ hybridization of bladder washings or voided urine, are of high value in monitoring NA of the urothelium.