The thymus is a small organ located above the heart and under the breast bone. It plays a role in the development of immune system cells known as lymphocytes. Thymoma occurs when a cell in the organ mutates and begins rapidly growing and dividing.
In addition to lymphocytes, the thymus is also made up of epithelial cells. These cells form the organ’s outer layer, known as the capsule. Thymoma develops from its epithelial cells, though lymphocytes can be mixed in with the tumor.
Thymoma that is contained within the capsule is early stage disease, while thymoma that has broken out of the capsule is more advanced.
Overall, thymoma is rare. Only a few hundred cases are diagnosed in the United States each year. Most patients are over 70 years old. Its five-year survival rate is about 70%, though the prognosis for each patient can differ based the disease’s subtype, stage and other factors.
Types of thymoma
There are three main types of thymoma:
Type A: This subtype has spindle-shaped epithelial cells that have turned cancerous. Depending on the patient’s specific cancer, the tumor may not include any lymphocytes, or it may have many lymphocytes. The prognosis for thymoma Type A patients is typically very good.
Type B: There are several subtypes of Type B thymoma. Each can have its own appearance under a microscope. The prognosis for this disease varies depending on the subtype.
Type C: This is the most aggressive type of thymoma. It is also called thymic carcinoma. Thymic carcinoma cells look very abnormal under a microscope. The disease has a high rate of metastasis, or spread to other parts of the body. In fact, many patients with thymic carcinoma are diagnosed after the disease has already spread.
Thymoma and myasthenia gravis
Because the thymus is part of the immune system, thymoma can cause patients to develop autoimmune diseases. These cause the body’s immune system to attack healthy cells.
Myasthenia gravis (MG) is the most common autoimmune disease caused by thymoma. MG causes muscle weakness as well as a number of symptoms involving the face, head and neck. If a patient has MG caused by thymoma, curing the thymoma also can resolve the MG.
Thymoma risk factors
A risk factor is anything that increases the chance that a person will develop a particular disease. There are few known risk factors for thymoma. The disease has not been linked to family history or specific behaviors.
The main risk factors for thymoma are:
- Age: Thymoma is rare in children and young adults. The disease becomes more common as people enter middle age, with the number of cases peaking among people in their 70s.
- Race: In the U.S., thymoma is most common among people with Asian/Pacific Islander heritage.
Why choose MD Anderson for your thymoma care?
Thymoma is a rare cancer and like all cancers, it can be serious. With just a few hundred cases diagnosed in the United States each year, it is important to find a team with experience treating this disease.
As a top-ranked cancer center, MD Anderson offers specialized treatments for thymoma patients. If you choose MD Anderson for your thymoma care, you will be treated by a multidisciplinary team of doctors and other care providers with special expertise in this disease. This team includes medical oncologists, surgeons, radiation oncologists and more. All are experts in their fields and the treatment of thymoma. They work together closely to customize the best treatment for you.
Groundbreaking research
MD Anderson's researchers are pioneering remarkable advances to give you the best chance for fighting thymoma. These include:
- Advanced surgical techniques that can improve outcomes while shortening hospital stays and recovery times.
- Targeted radiation therapy that focuses on cancer cells while minimizing damage to healthy nearby tissue.
- New cancer medicines, including immunotherapies that recruit the body’s own immune system in the fight against cancer and targeted therapies designed to slow or stop the disease’s growth.
Many clinical trials at MD Anderson are not available at other cancer centers. In fact, we offer clinical trials for various stages of thymoma, including treatments for thymoma in its early stages, thymoma that has spread to other parts of the body, and thymoma that has returned after earlier, successful treatment.
And, at MD Anderson you're surrounded by the strength of one of the nation's top-ranked cancer centers. We have all the support and wellness services needed to treat the whole person – not just the disease.
I found the reassurance I needed the minute I set foot inside MD Anderson’s doors.
Treatment at MD Anderson
MD Anderson thymoma and thymic carcinoma patients can get treatment at the following locations.
MD Anderson's Proton Therapy Center
