[Imaging of small renal tumors]

The increased incidence of detection of small renal tumours, less than or equal to 3 cm in diameter, is related to the generalization and improvement of radiological techniques. Many asymptomatic renal tumours are discovered by ultrasonography and computed tomography. Medical imaging is now able to identify simple cysts (morphological characters, absence of blood supply), angiomyolipomas (demonstration of the fatty contingent) and other solid renal tumours (tumour enhancement on computed tomography). Plain, followed by postcontrast CT looking for contrast enhancement of the lesions is the examination of choice in this context. MRI with Gadolinium injection looking for neoplastic enhancement can be useful in doubtful cases. Medical imaging is able to reliably demonstrate the vascular nature of solid lesions, but cannot distinguish between renal cancer, oncocytoma or another benign solid tumour. Medical imaging allows precise preoperative mapping when partial nephrectomy is envisaged.