Involution rate of multicystic renal dysplasia

Objective. To document the involution rate and long-term results of managem ent of multicystic dysplastic kidney. Materials and Methods. Data were collected retrospectively for all 23 infan ts (16 boys) with multicystic dysplastic kidney who were treated at our cen ter over the last 19 years (1977-1995). The diagnosis was based on prenatal ultrasound in 18 patients and on palpable abdominal mass in 5, and confirm ed in all patients by postnatal ultrasound and radioisotope scan. Voiding c ystography was performed in 18 patients to exclude vesicoureteral reflux. M ean follow-up was 46 months (range, 3 months to 5 years) and included serum creatinine measurements and renal ultrasonography. Results. Two groups of patients were identified. Ten (43.6%) with other uro logic abnormalities (group A) and 13 patients without other urologic abnorm alities (group B). Vesicoureteral reflux was observed in 4 patients. Nephre ctomy was performed in 4 patients,;all from group B. The other 19 patients were treated conservatively. Complete involution was observed in 8 patients in group A and 6 in group B after a mean follow-up period of 9.2 and 10 mo nths, respectively. Two patients, 1 from each group, later underwent nephre ctomy not because of no involution but because of an increase in the size o f the kidney involved. Conclusion. Patients with multicystic renal dysplasia have significant asso ciated urologic malformations, and the natural history of the disease is un predictable. All patients require appropriate investigation of the urinary tract and long-term follow-up. The most outstanding finding of the study is the much higher involution rat e of multicystic renal dysplasia and the rate of associated urologic abnorm alities than that reported in the literature. Surgery remains an option for the patients in the absence of no involution.