(a) Unenhanced CT demonstrates a cm upper pole lesion of the left kidney with a central hypodense area representing necrosis or hemorrhage (arrows). The tumor formation shows hyperattenuation as compared to the normal cortex and it is protruding from the periphery towards the renal sinus. There are no typical intratumoral fatty zones, (b) following i.v. contrast the lesion exhibits inhomogenous enhancement with an increase of 35 HU; the lesion is in close proximity to the renal sinus. Attenuation values are lower than those of the adjacent renal cortex with an increase of 165 HU.