Renal cysts remain the most common of benign renallesions, representing more than 70% of asymptomatic renalmasses.• The overwhelming majority of simple or minimally com-plex cysts require no further follow-up or therapy oncediagnosed.• The Bosniak classification for renal cystic lesions is the mostuseful and widely employed method for characterizing renalcystic lesions and assessing the likelihood of the presence ofa concomitant malignancy within the cyst.