From your feeling of it to be soft like gum, it is more likely to be a cyst. Lymphoma is a type of blood cancer that occurs when B or T lymphocytes, the white blood cells that form a part of the immune system and help protect the body from infection and disease, begin behaving abnormally. Abnormal lymphocytes may divide faster than normal cells or they may live longer than they are supposed to. Lymphoma may develop in many parts of the body, including the lymph nodes, spleen, bone marrow, blood or other organs and eventually they form a mass of cells called a tumor. Fine needle aspiration cytology ( a kind of tissue cells study under microscope) is generally a first step before surgery.You may enquire for this from your treating Doc.