Multicystic dysplastic kidney detected by fetal sonography: conservative management and follow-up

The most common cystic lesion recognized antenatally is multicystic dysplas tic kidney (MCDK). Recently, conservative management without nephrectomy ha s been advocated. The purpose of this study was to report our experience in the conservative management of unilateral MCDK. Between 1989 and 1997, 20 children with MCDK detected by prenatal ultrasonography (US) were prospecti vely followed. At birth, US confirmed the prenatal findings in all cases. A ll patients were submitted to radioisotope scans and a micturating cystogra m. Follow-up US examinations were performed annually. Mean age at diagnosis during the prenatal period was 31 weeks of gestation (range 24-38). Median follow-up time was 33 months (range 7-91). Follow-up US was performed in 1 9 children; 13 (68%) showed partial involution, 4 (21%) complete involution , and 2(11%)an increase in unit size. The mean age at complete or partial i nvolution of the lesion was 18 months. No children developed hypertension o r tumors, and all maintained normal growth. In conclusion, the natural hist ory of MCDK is usually benign, and serial US examinations show that affecte d kidneys frequently show involution with time.