Fig. 1

A computed tomography (CT) urogram was performed. Axial and coronal computed tomographic images of the abdomen demonstrating a 6.0 × 4.7 cm irregular mass centered within the superior pole of the right kidney. On the axial noncontrast image (a), the mass is non-homogeneous with the most portions being isodense to the normal renal parenchyma and with central hypoattenuating areas suggestive of necrosis. During the corticomedullary phase (b), the nephrographic phase (c) and the coronal excretory phase (d), the solid component of the mass mild-moderately enhances but not as avidly as normal renal cortex. The central low density necrotic areas and the margin become more conspicuous