Preschooler with abdominal pain

CT and ultrasound of a simple renal cyst
Axial (above left) and coronal (above right) CT with contrast of the abdomen show a round low density lesion in the upper pole of the right kidney. Sagittal US of the right kidney (below) shows an anechoic lesion in the upper pole of the right kidney that has a thin wall and no internal septations or calcifications.

The diagnosis was simple renal cyst.