Radiology: Volume 249: Number 1—October 2008
Stuart G. Silverman, MD Gary M. Israel, MD Brian R. Herts, MD Jerome P. Richie, MD
Despite substantial advances in the imaging-based diagno¬sis of renal masses, the increased detection of incidental renal masses with cross-sectional imaging poses problems to the radiologist and referring physician. Most incidental renal masses can be diagnosed with confidence and either ignored or treated without further testing. However, some renal masses, particularly small ones, remain indetermi¬nate and require a management strategy that is both med¬ically appropriate and practical. In this article, the litera¬ture will be reviewed and an approach to the diagnosis and management of the incidental renal mass will be sug¬gested. Management recommendations, derived from data regarding the probability of malignancy in cystic and solid renal masses, are provided for two types of patients, those in the general population and those with limited life ex¬pectancy or co-morbidity. The Bosniak classification is used to guide the management of cystic masses, with ob¬servation reserved for selected patients, and the presump¬tion of benignity recommended for simple-appearing cystic masses smaller than 1 cm. Among solid renal masses, a more aggressive overall approach is taken. However, addi¬tional imaging, and in selected patients, percutaneous bi¬opsy, is recommended to diagnose benign neoplasms. Al¬though additional studies are needed to establish risks and benefits, observation of solid masses may be considered in selected patients. Minimally invasive treatments of renal cancer (including percutaneous ablation) show promise but at the same time challenge the radiologist to review the approach to the incidental renal mass.