From the Gundersen Clinic, La Crosse, Wisconsin ABSTRACT-Unilateral renal dysplasia in a horseshoe kidney is very uncommon. A case which was detected in utero is presented. The management of multiastic kidneys is reviewed.

The incidence of horseshoe kidneys is reported to be 1 in 265 to 1 in 1,800 births’ (commonly quoted 1 per 400). Multicystic kidney disease recently was reported as 1 in 4,300 live births2 The combination of a horseshoe kidney with unilateral multicystic dysplastic kidney is rare. A review of the literature has revealed 3 cases.1,3,4 A brief reference to 8 other cases is reported in other series. l To my knowledge, this is the first one detected in utero. Case Report The patient was the product of an uneventful pregnancy and cesarean section delivery. In utero ultrasound of the left kidney demonstrated an abnormality consistent with multicystic kidney disease (Fig. 1A). At birth, a left renal mass was palpated. The remainder of the physical examination was unremarkable. Renal ultrasound of the baby was suggestive of left

multicystic kidney disease, but a ureteropelvic junction obstruction was not ruled out completely (Fig. 1B). Therefore, a glucoheptenate scan was obtained which demonstrated some mild function on the left but also suggested a horseshoe kidney (Fig. 2). To delineate the anatomy better, a CT scan was obtained, and a horseshoe kidney with multicystic renal dysplasia was confirmed (Fig. 3). A VCUG demonstrated no evidence of reflux. Because of the potential risks and the infrequent occurrence of this abnormality, it was thought that surgical removal of the muiticystic portion of the horseshoe kidney was indicated. Therefore, the patient underwent an uncomplicated left nephrectomy and isthmusectomy. The specimen demonstrated findings consistent with multicystic renal dysplasia grossly (Fig. 4A) and microscopically (Fig. 4B). Postoperatively, the patient did well, and his convalescence at home was unremarkable.

FIGURE 1. Ultrasound (A) in utero shows dilated left renal collecting system, and (B) in newborn demonstrating dilated cystic structures of left renal unit.




1992 / VOLUME 40, NUMBER 5


FIGURE 2. Glucoheptenate horseshoe kidney.

renal scan suggests

Abdominal CAT scan demonstrating isthmus of horseshoe kidney.


(A) Gross specimen demonstrating multicystic renal dysplasia, and (B) histologic section illustrates typical findings of multicystic kidney disease (original magnijication reduced from x 10). FIGURE 4.





to 136 pediatric urologists, 15 percent responded that they had seen or treated patients with multicystic kidney and hypertension.” They believed that multicystic kidneys were a more common cause of hypertension than the literature suggested and that routine surveillance of these patients usually was not satisfactory. They believed that follow-up of patients with multicystic kidneys should be rigorous and concluded that elective nephrectomy was certainly a reasonable alternative to life-long follow-up with attention to blood pressure determination. This is the first reported case of in utero detection of unilateral renal dysplasia in a horseshoe kidney. This is a rare congenital anomaly which was previously noted at autopsy or during resection of a large abdominal mass. At the present time, the role of nephrectomy and the management of unilateral asymptomatic multicystic kidneys is in transition, and further study is needed to assess the potential problems that arise from kidneys that are followed up.

Comment A horseshoe kidney results from fusion of two nephrogenic blastemas. 3 There is an associated genitourinary anomaly in about 25 percent of patients with horseshoe kidneys including duplication, ureteroceles, vesicoureteral reflux, 3.5,6 undescended testes, and hypospadias. Horseshoe kidneys have been associated with teratogenic factors both genetic (Turner’s syn3 drome) and environmental (thalidomide). Multicystic kidney disease is a developmental anomaly of the kidney in which the renal parenchyma is replaced by tense noncommunicating cysts, and the proximal ureter is atretic or nonpatent. Prior to ultrasound, the diagnosis was made when the child presented with an abdominal mass. Gordon et ~1.~ reported on 23 patients with unilateral multicystic kidney disease of which only three had readily palpable lesions. They suggested that the majority of unilateral multicystic kidney disease probably had gone undiagnosed until the advent of prenatal ultrasound screening. In reviewing the indications for nephrectomy in unilateral multicystic kidney disease, they believed there was no strong justification for routine nephrectomy. At the 1988 annual meeting of the Section of Urology of the American Academy of Pediatrics, approximately 60 percent of those in attendance believed that asymptomatic multicystic kidneys should be left in place.6 In a recent article by Susskind, Kim, and King,” they reported 2 cases of hypertension in infants with multicystic kidneys who were both treated with nephrectomy and subsequent cure of their hypertension. They expressed concern over surveillance of patients who have a known multicystic kidney, and believe that it may be inadequate. In an informal questionnaire sent







1836 South Avenue La Crosse, Wisconsin 54601 References 1. Akltar M, and Valencia M: Horseshoe kidney with unilateral renal dysplasia, Urology 13: 284 (1979). 2. Cordon AC, Thomas DFM, Arthur RJ, and Irving HC: Multicystic dysplastic kidney: is nephrectomy still appropriate?, J Ural 140: 1231 (1988). 3. Novak ME, Baum NH, and Gonzales ET Jr: Horseshoe kidney with multicystic dysplasia associated with ureterocele, Urology 10: 456 (1977). 4. Towbin R, Benton C, and Martin L: Multilocular cystic dysplasia of half of a horseshoe kidney, J Pediatr Surg 9: 421 (1974). 5. Discussion: Pediatric tumors, presented at Annual Meeting of Section of Urology, American Academy of Pediatrics. J Ural (Pt. 2) 142: 489 (1989). 6. Susskind MR, Kim KS, and King LR: Hypertension and multicystic kidney, Urology 19: 362 (1989).



In utero detection of horseshoe kidney with unilateral multicystic dysplasia.

Unilateral renal dysplasia in a horseshoe kidney is very uncommon. A case which was detected in utero is presented. The management of multicystic kidn...
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