@seram, There is a big difference between a tumor and a cyst. A tumor is solid and may impinge on other organs (because it is in your torso). A cyst is a fluid-filled sac that may also impinge on other organs. If I remember correctly cysts are usually not cancerous but tumors may be. Sometimes additional testing may be done to determine 1) whether it is a tumor or cyst, 2) if it can be determined to be growing and how rapidly, and 3) if it may be cancerous. You may need more than a General Practitioner to get a firm diagnoses and treatment plan.