Renal masses in adults. Differentiating benign from neoplastic causes.

Diagnostic evaluation of renal masses in adults has been a perplexing problem. With the advent of new imaging methods over the past 15 to 20 years, the best approach has varied from institution to institution, depending on the equipment available and the preference of the physician. A diagnostic algorithm is presented here to guide the physician in determining the order in which certain techniques should be considered, thus avoiding unnecessary tests and cutting healthcare costs. In general, benign masses, malignant masses, and pseudoneoplasms have characteristic features that distinguish them from each other if the physician knows how to use the various imaging techniques and interpret results.