Cyst: A cyst is an abnormal, closed sac-like structure within a tissue that contains a liquid, gaseous, or semisolid substance. A cyst can occur anywhere in the body and can vary in size. The outer, or capsular, portion of a cyst is termed the cyst wall.
Tumor: A swelling of a part of the body, generally without inflammation, caused by an abnormal growth of tissue, whether benign or malignant.
They are different.
You can find a lot of research on this diagnosis. First of all, I'm sorry for the problems you are having. A cyst is defined as a fluid filled sac. Cysts are not known to be cancerous, because they have fluid and not cancer causing cells. A tumor is filled with tissue. Sometimes they are cancerfilled and sometimes not which is called benign. A cyst is usually round with smooth edges, like a balloon filled with water and a tumor can be smooth, but a cancerous tumor can be lumpy and have legs that reach out into other parts of the tissues next to it. Hope this helps you and good luck with everything.
Lilyrose77