Kidney cyst can be simple or complex.
Simple cysts are usually single with smooth walls & is a common finding after 50 years of age.
They usually do not produce symptoms and may be detected first time by CT or other imaging studies.
In complex cysts the walls are not smooth, there may be walls within it etc. Some of the complex cysts can be cancerous.
In some cases the walls of the cyst can get calcium deposition when it is called calcified cyst.
Usually the urologist will consult the radiologist about the shape & characteristics of the cyst & can select to do biopsy to determine the nature.
I hope this information will help. Please ask if you need any clarification. Best wishes.
If it is causing pain then there may be any pressure effect of the cyst on adjacent kidney tissue.
You will need treatment to relieve it. Doctor may decide aspiration or surgery depending on its nature.