I had a cyst on the back of my neck drained (not sure what kind of cyst, but it wasnt cancer) They removed most of the sac. The nurse said about 90 % of the sac was removed. Do I need to have the remaining piece of sac removed, or can I just leave it there? I don't have insurance, so it would cost me quite a bit to see a surgeon. The cyst was about 2 inches from my spine, which is why they refered me to a surgeon.