The question that you ask is a urological question and best answered by a urologist, who is a surgeon. I am a nephrologist and do not have expertise in this area. I suggest you continue to consult with the urologist. If you are concerned, you could seek a second opinion, but a simple cyst in a kidney can be a normal finding, despite being 7.5 centimeters (cm) in size. About 40% of patients develop cysts in their kidney as they age.