Lymphoma is a disease in which lymphocytes (i.e. blood cells that fight infection) turn into cancer cells. In thyroid lymphoma, the lymphocytes of the thyroid turn into cancer cells. Thyroid lymphoma is a very rare disease that accounts for 1 to 2% of all thyroid cancers and 1 to 2% of all lymphomas outside the lymph nodes. Most patients are older with an average age in the late 60's. If properly diagnosed and treated, the prognosis is very good.
Signs and Symptoms
Unlike most thyroid cancers which do not cause symptoms, thyroid lymphomas tend to grow very quickly (sometimes over a few weeks) and cause compressive symptoms which include difficulty swallowing, food or pills getting "stuck" when they swallow, and pressure or shortness of breath when lying flat. Patients typically notice a firm mass they can feel or a visible mass (i.e. a mass they can see). In some cases, patients may develop hoarseness or difficulty swallowing. Patients with compressive symptoms, enlarged lymph nodes, hoarseness, and/or a rapidly growing mass in the neck, should seek medical evaluation right away.
As with other forms of lymphoma, patients may develop "B-symptoms" which include weight loss, fevers, night sweats, and total body itchiness.
Patients with a history of a rapidly growing neck mass with or without compressive symptoms should be evaluated immediately. Other forms of thyroid cancer that can present like a thyroid lymphoma include anaplastic thyroid cancer and advanced medullary thyroid cancer. It is critical to differentiate between an anaplastic thyroid cancer and thyroid lymphoma because the treatment and prognosis are very different. A FNAB can sometimes distinguish between thyroid lymphoma and another cause, but sometimes a core needle biopsy (i.e. biopsy with a large needle), and often a surgical biopsy is necessary. After the diagnosis of thyroid lymphoma is made, total body PET scan may be done to look for lymphoma elsewhere in the body in order to stage the patient.
Chemotherapy is the treatment of choice for most thyroid lymphomas. Often within giving a few doses of chemotherapy, the thyroid lymphoma shrinks in size. Chemotherapy is so successful in treating thyroid lymphoma that surgery is seldom necessary. External beam radiation may be used to help shrink the lymphoma while the chemotherapy is being given.