A spectrum of segmental multicystic renal dysplasia.

Background: Multicystic renal dysplasia (MCDK) is a common anomaly well described in the literature, but less well described when involving only a portion of a kidney.

Objective: To present the imaging spectrum, natural history and associated anomalies of six kidneys with segmental MCDK.

Materials And Methods: Five children with segmental MCDK (one with bilateral segmental MCDK) referred to our hospital between 1989 and 1996 were reviewed. All had at least one ultrasound examination. Four had a voiding cystogram and three had renal scintigraphy.

Results: Four children had antenatal diagnosis of cystic renal abnormality. In two, with obvious duplex kidneys and associated ureteroceles, the diagnosis of upper moiety MCDK was obvious either antenatally or immediately postnatally. In the other three there were diagnostic difficulties. One patient had bilateral widespread cysts obscuring the functioning renal portions. Another presented in utero with a large ureterocele and a cystic upper pole that had involuted by birth. The fifth had a nephrectomy at 3 years for a multiloculated cystic mass. Varying degrees of involution occurred in the five kidneys seen early. Reflux was demonstrated into the ipsilateral functioning lower moiety and midpole.

Conclusion: In these children as in other studies, the commonest presentation of segmental MCDK is in the upper pole of a duplex kidney associated with a ureterocele at the end of the atretic ureter. Atypical segmental MCDK may present a diagnostic dilemma and should be included in the differential diagnosis of multiloculated cystic masses and cystic kidneys.