Thyroid lymphoma is a cancer of the lymphatic system that arises from the thyroid gland. The lymphatic system is part of the body's immune system that helps fight infection. It is made up of organs such as the bone marrow, thymus, spleen, and lymph nodes. Primary thyroid lymphomas are usually always non-Hodgkin lymphomas (NHLs) and can be divided into aggressive and slowly developing cell types. The most common symptoms of thyroid lymphoma is a lump in the front of the neck. Once diagnosed, thyroid NHL is highly curable without the need for surgery. Treatment may include radiotherapy, chemotherapy, or steroids. It usually occurs in people over the age of 60 and is more common in women than in men.