The child with renal cysts

Renal cysts of different aetiology are a common diagnosis in paediatric nephrology. The classification is usually based on the clinical picture, morphology, and family history. In syndromic forms, additional features have to be evaluated. Most common are cystic dysplastic kidneys with a broad phenotypic spectrum ranging from asymptomatic clinical courses in unilateral cases to severe, lethal manifestations in patients with considerable bilateral involvement. Simple cysts are rare. Polycystic kidneys are usually subdivided according to the mode of inheritance into autosomal recessive and autosomal dominant polycystic kidney disease. The most useful investigation in order to distinguish between these two types is the family history with parental ultrasound and demonstration of polycystic kidneys in one parent in the majority of cases with dominant polycystic kidney disease. Finally, cystic kidneys are associated with a variety of hereditary, usually recessive syndromes affecting cilia.