Polycystic horseshoe kidney anomaly

Wednesday, 02 Sep 2009 16:24:29 GMT

A 31-year-old man presented with an incidental finding of microscopic hematuria during a routine check-up. In complementary work-ups, a high serum BUN and creatinine level were also noted, and a renal ultrasound was performed. The ultrasound showed multiple bilateral renal cysts with suspicious bilateral hydronephrosis. Exact evaluation of the hydronephrosis was impossible due to the presence of numerous kidney cysts.

Laboratory findings were:

normal CBC,
microscopic hematuria (8-10 RBC/ HPF)
no pyuria,
serum BUN = 45
creatinine = 2.1
other findings were normal.

The physical examination was normal but the patient said that he experienced occasional vague abdominal pains for a few months. He also stated that his mother had undergone renal transplantation about 15 years ago and that 4 of his cousins had renal failure and were under hemodialysis.

We performed bilateral ureteroscopy to rule-out the obstructive nephropathy. The left ureter was normal but there was a moderate stenosis in the right ureter and a double-pigtail ureteral stent was placed. On performing a kidney-ureter-bladder (KUB) radiograph to assess the correct position of the stent, we noted an unusual stent path (Figure 1). We performed an abdominal computed tomography (CT) scan to rule-out mass lesions that could possibly displace the right ureter. We were unable to perform an intravenous pyelogram because of the high creatinine levels. On CT scan, we found that the kidneys were also in a horseshoe formation (Figure 2) and the diagnosis of polycystic horseshoe kidney was confirmed. Since the serum creatinine level remained unchanged, the stent was removed and no hydronephrosis was observed on repeat renal ultrasound (Figure 3).

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Polycystic horseshoe kidney anomaly