A variety of therapy related changes are observed in the urinary bladder an
d urinary cytology but most are non-specific. Practical problems in evaluat
ing therapy related lesions are of great importance in cytology specimens a
nd biopsies in which therapy associated cytologic atypia remains the most c
ommon cause of false-positive reports. Accurate assessment of treatment eff
ects on the bladder is often further confounded by lack of information conc
erning the condition of the patient before therapy and the duration of expo
sure to the regimen. To avoid diagnostic pitfalls, clinicopathologic correl
ation is mandatory.