Clinical Presentation

A 10-year-old with a flank mass.

A longitudinal sonogram of the right kidney demonstrates multiple large renal cysts that do not connect with one another or the renal pelvis (arrows). The left kidney had a virtually identical appearance.

Differential Diagnosis

• Autosomal-dominant polycystic disease: The finding of multiple large renal cysts bilaterally is typical of this disorder.

• Simple renal cysts: