A renal lesion is first evaluated using ultrasound. If it is consistent with a simple cyst, the investigation need not go any further. In the case of a complex cyst, a CT scan is the preferred exam method to evaluate its overall enhancement and the presence or not of enhanced septations or intracystic nodules, in order to classify their neoplastic risk, based on the Bosniak classification system. Magnetic resonance imaging is indicated with patients who are allergic to iodine or who suffer from kidney failure (but with a glomurelar filtration rate of <30ml/min/1.73m2>), with complex cysts or ambiguous CT scan results.
Ultrasound detection of a solid lesion will be followed up using a CT scan for staging (adenopathies, renal vein thrombosis).