Purpose: The growing availability of modern-day imaging has resulted in an increase in the number of renal cysts detected in the pediatric population. Few publications have reported outcomes of these childhood cysts. In this study we assessed the prevalence and evolution of renal cysts in children, and described clinical characteristics, mode of presentation and ultimate outcomes.
Materials and methods: Our institutional ultrasound database was searched for all abdominal ultrasound reports from 2006 to 2017. These reports were then cross-referenced with a manual retrospective chart review. Clinical characteristics including mode of presentation, cyst characteristics, and outcomes were analyzed using descriptive and nonparametric statistical methods.
Results: Of 70,500 abdominal ultrasound scans during the study period 1,531 (2.2%) met the study inclusion criteria. Overall 26% of cysts were complex and 10.1% of cases were associated with hydronephrosis. Echogenic kidneys were more likely to be associated with simple cysts (p=0.0001). There was no difference between cyst diameter and symptomatology (p=0.82). The conversion of simple to complex renal cysts was less than 1% and 1.8% of complex cysts developed renal cell carcinoma.
Conclusions: In a large cohort of children who underwent abdominal imaging we found a 10-year renal cyst prevalence of 2.2%. Given that nearly all cysts follow a benign course and that simple cysts will invariably grow within 2 years, we believe that these cases could be safely discharged after that point. We continue to recommend surveillance for patients with cysts larger than 15 mm, complex cysts, family history of adult polycystic kidney disease or those with concomitant genitourinary anomalies requiring ongoing followup.
Keywords: classification; cystic; kidney diseases; treatment outcome; ultrasonography; watchful waiting.