A renal cyst is a fluid filled cavity of the kidney.The development of renal cysts is not very clear. It is not a genetic hereditable disease, though there may exists certain malformations that are hereditable and can thus encourage the devlopment of a renal cyst. They occur rather rarely before the age of 50 and often develope in course of other diseases like the polycystic kidney disease (either autosomal dominant or autosomal recessive) , Von Hippel Lindau disease,the meckel syndrome or nephronophtisis.In most cases, renal cysts remain undiagnosed and are accidentally found during an examination. However, they can also cause a strong pressure pain in connection with lower abdominal pains and by blocking the calix it can even lead to urinary obstruction.There may also be inflammations or renal hypertonia.The ADPKD is from its name a genetic disease which is inheritedin a autosomal dominant way and classified by renal cysts.