Coronal (left) and axial (above right) images from a CT with contrast of the abdomen obtained soon after the injection of contrast (nephrographic phase) show a claw sign in the right kidney encasing a large round low density lesion in the lower pole of the right kidney. The Hounsfield unit of the cystic lesion was that of water. Axial delayed image (excretory phase) from the same exam (below right) shows no contrast in the cystic structure.
The diagnosis was a simple renal cyst and not a calyceal diverticulum.
Pediatric Imaging 