Teenager with right flank pain

CT and US of pediatric cystic nephroma
Axial (above left) and sagittal (above right) CT with contrast of the abdomen show two multiseptated low density lesions in the superior and middle poles of the right kidney. Sagittal US of the right kidney (below) show the two lesions are anechoic and filled with multiple thin septations without any nodularity.

The diagnosis was pediatric cystic nephroma.