I have a 1.2 cm cortical cyst in my mid pole on my kept kidney that was in 2008, my doctor said since its not a tumor, no further treatment is needed.  I was crying that time when I found out but my urologist got upset with me and said even if you go to a different doctor they will not do anything.
Hello and welcome to Chat Doctor. As a Urologist, let me assure you that, a simple cortical cyst is normal. You should mention your age and gender. A very important thing you should do is, to get an annual scan, to see if, there's any change in size of cyst or within the cyst. A single, simple cyst is best left alone. So, don't worry at all.  But, go and get another scan done. You may send me the report, as a direct question, for expert opinion. Chat Doctor.  Manga.