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

This baby girl was found to have a left multicystic dysplastic kidney in utero and this was confirmed after delivery. The kidney had shrunk and much of the fluid in the cysts had resorbed (Figure 1). A voiding cystogram showed weakness of the left side of the bladder near the trigone with a diverticulum-like structure (Figure 2). Physical examination showed a left periurethral cyst filled with clear fluid. The cyst was injected and contrast material filled an ectopic ureter that ended blindly at the cyst and the ureter went part of the way to the multicystic kidney. Just below the kidney, the ureter was atretic (Figure 3). This patient demonstrates that although many cases of multicystic dysplasia are due to ureteropelvic atresia, sometimes the obstruction can be in the lower urinary tract and part of a more extensive anomaly.