Multicystic dysplastic kidney: our experience in non-surgical management

Although multicystic dysplastic kidney (MDK) is a common renal anomaly, the management of this condition remains controversial. The purpose of this study was to focus on its regression by ultrasound (US) scan for MDK managed conservatively. Between 1990 and 2010, 50 children with MDK were retrospectively studied. All patients were submitted to radioisotope scan to confirm the diagnosis, and a micturating cystogram to exclude other uropathies. Of the 50 patients, 19 underwent nephrectomy, and the other 31 were conservatively managed with clinical and US scan follow-up. The mean follow-up time (range 6 months to 11 years) in the non-operated group was 6.2 years. Of the 31 children with nonsurgical management, 17 (54.8%) showed total involution on US scan, 7 (22.6%) showed a partial regression, and 7 (22.6%) were unchanged at the time of this study. The mean time to complete disappearance on US scan was 2.5 years (1-4 years). No children developed hypertension or tumors. The natural history of MDK is usually benign, but patients must have long-term follow-up with US scan. In addition, many studies confirmed that the disappearance of it on a US scan does not mean a total involution of the affected kidney. We recommend a strict follow-up even when US scan shows an undetectable kidney.