Robert L. Lebowitz, M.D. Children' s Hospital, Harvard Medical School Boston, Massachusetts

Multicystic Dysplastic Kidney in Lower Pole of Duplex Kidney

Prenatal diagnosis of "hydronephrosis". Ultrasound after delivery showed left duplex kidney with normal upper pole and multicystic dysplasia affecting lower pole (Figure 1) and (Figure 2). There were at least four cysts of different size replacing the lower pole of the kidney with no normal renal parenchyma. Multicystic dysplasia can be seen anywhere a kidney or part of a kidney resides. Multicystic dysplastic kidneys have been reported in one-half of a horseshoe kidney, in either the upper or lower pole of a duplex kidney, in a pelvic kidney, in one of crossed-fused ectopic kidneys, etc. The fact that it is the lower pole of a duplex kidney that has multicystic dysplasia should not necessarily be an indication to deviate from the usual nonoperative approach.