[Cystic diseases of the kidney].

Cystic diseases of the kidney constitute a heterogeneous family. Most renal cysts are benign and asymptomatic, and don't have any impact on renal function. These "simple" cysts are usually managed conservatively. However, some renal cysts may be symptomatic or may have atypical radiological presentation, leading to suspicion of malignant tumour; puncture or surgical investigation may be indicated in such cases. The other cystic renal diseases include specific entities, either genetic or acquired during development. Some malformative syndromes are often associated, and renal function may be impaired. In such cases, nephrectomy is required.