School ager with a right abdominal mass

CT of Wilms tumor
Axial CT without contrast of the abdomen (above) show a large right renal mass with some coarse calcifications within it. Axial CT with contrast (middle and below) shows a low density mass to be arising from the hilum of the right kidney and to be approaching the midline. The inferior vena cava appears to be clear of tumor as does the left kidney.

The diagnosis was Wilms tumor.