The radiologic evaluation of renal metastases

Renal metastases can arise from practically any primary neoplasm and should no longer be considered rare. Such lesions are usually detected during surveillance US or CT examinations. Appearances favoring metastases over an additional renal carcinoma are multiplicity, bilaterality, metastatic disease elsewhere, and perinephric disease. Since not all renal metastases behave predictably and may even appear as single, exophytic lesions, guided fine-needle aspiration may be required when such information will alter patient management.