Dysplastic multicystic kidney: should the classic treatment (nephrectomy) be changed after prenatal diagnosis?

We reviewed 60 cases of multicystic renal dysplasia managed in our institution during a 10-year period, 54 of which were prenatally detected; 59 were unilateral dysplastic multicystic kidneys (DMK) and 1 bilateral. The mean gestational age at diagnosis was 28.1 weeks. Associated anomalies were present in 17 cases; 4 of these infants died. In 19 cases, a nephrectomy was initially performed. Among the 37 infants initially managed nonoperatively, 4 were lost to follow-up. The DMK was removed in 17 instances after 18 months of age (mean age 26.8 months), and 16 children with spontaneous regression of the lesion were followed. In 9 cases, complete disappearance of the dysplastic kidney was observed. Of the 36 kidneys removed, most were of the dysplastic type; a ureter was present in 21 cases and no nodular renal blastema was found. When opacification of the specimen was performed, communication between cysts was the most frequent finding. The critical question of the harmlessness of nonoperative management of DMKs has to be answered by a large-scale, long-term, multicenter study.