Unilateral hyperechoic renal pyramids in a child with renal artery stenosis

With most conditions that result in hyperechoic renal pyramids, the involvement is usually relatively homogeneous and symmetric, involving all pyramids and both kidneys. An exception to this pattern has been shown in furosemide-induced medullary nephrocalcinosis (MNC), in which the renal involvement may be asymmetric but rarely unilateral. Cases of markedly asymmetric MNC with hyperechoic pyramids predominantly involving 1 kidney have been previously described in children with specific contralateral unilateral renal disease, such as renal vein thrombosis and hydronephrosis. The purpose of this report is to illustrate the case of a girl with substantial unilateral renal artery stenosis who was found to have unilateral hyperechoic renal pyramids in the contralateral kidney, possibly due to MNC. To our knowledge, this finding in this clinical setting has not been previously reported in the literature. © 2006 by the American Institute of Ultrasound in Medicine.