Describe the CT findings of RCC.

Mass showing decreased attenuation on noncontrast CT compared with normal kidney
Possible early hypervascularity and enhancement on arterial phase scans
Less-than-normal enhancement on non-equilibrium and nephrogram phase scans, usually heterogeneous
Thick wall, irregular margin
Calcified in 10% to 20% of patients (87% nonperipheral calcification)
Possible renal vein or IVC thrombus, neoplastic (tumor) or not (bland)
Possible periaortic adenopathy
Liver metastases possibly hypervascular (do triphasic liver CT)
Bilateral RCC in a small percentage of patients (incidence increased in patients with von Hippel-Lindau disease)