Is cyst dangerous to leave

I have been told I have a softball size fluid cyst on my left kidney.  I was told it was no big deal by the urologist and that if it were him he wouldn't do anything.   Sounds awfully big to me to just leave in there.  SHould I be concerned?

[Dr Santos]

Hi,

Kidney cysts are almost always benign and do not cause any problems. Some people can even go through life without even knowing that they have them. If there are associated symptoms such as pain on your side between your ribs and your hip, pain in your belly or back, a fever, frequent urination or blood in your urine other laboratory tests may be done. Otherwise, there is no treatment needed. A follow up appointment and a CT scan is repeated after 6 to 12 months. If your kidney cyst is large or if it contains calcifications or dense tissue, you might need to have CT scans every so often so that your doctor can watch for changes in the cyst. Most kidney cysts are harmless and do not need to be removed.  You might be referred to a urologist if the cyst keeps getting bigger, if you have problems because of the cyst or if there is any concern that the cyst might be cancerous.

I hope this helps. Take care and regards.