MODERN radiologic technics of urography often detect asymptomatic renal masses. Even though occult renal masses are now found more frequently, there is no generally agreed upon protocol for distinguishing benign lesions, such as simple cysts, from renal cancers. The purpose of this report is to present a safe, economical and reliable approach to the asymptomatic renal mass based on our own experience and that of others.Diagnostic TechnicsThe admission examination and the results of laboratory tests often predict the nature of a renal mass. Approximately 80 per cent of patients with renal-cell cancer have some evidence of the malignant . . .