Thymoma & Thymic Carcinoma Symptoms

Man with shortness of breath speaking to nurse

Thymoma and thymic carcinoma are uncommon cancers, but it’s important to be aware of their symptoms and know when to speak with a physician. These thoracic diseases occur when cancerous cells form on the outside surface of the thymus—a small gland in the chest behind the sternum that produces T lymphocytes, or “T cells” that play a key role in immune system function.

Both thymoma and thymic carcinoma are cancers of the thymus, but they differ slightly in that:

  • Thymoma tumor cells appear similar to healthy thymus cells when examined under a microscope. They tend to grow slowly and rarely spread beyond the thymus.
  • Thymic carcinoma tumor cells appear abnormal when viewed under a microscope and grow more rapidly than thymoma tumor cells.

Thymoma and thymic carcinoma symptoms may vary from one person to the next depending on the cancer’s stage and specific location within the chest. Some patients never notice anything out of the ordinary, while others experience disruptive respiratory symptoms. For example, many tumors that form in the thymus can affect surrounding structures, triggering symptoms like:

  • Chest pain
  • Difficulty swallowing
  • Shortness of breath
  • Coughing that may produce bloody sputum
  • Loss of appetite
  • Weight loss

If the tumor presses against the superior vena cava—the primary blood vessel that delivers blood from the upper body down to the heart—it can produce a distinct group of symptoms known as superior vena cava syndrome. These symptoms include:

  • Swelling in the face and upper body, sometimes with bluish skin
  • Swelling of visible veins in the face, neck and chest
  • Dizziness or lightheadedness
  • Headaches

Because thymoma and thymic carcinoma usually weaken the immune system, frequent infections are another possible sign of thymus cancer. Symptoms can be similar to those produced by chest colds, pneumonia and other less serious conditions, so a physician may first suspect a more common illness until additional testing measures like imaging scans and lab tests are completed.   

Anyone can develop thymoma or thymic cancer, but it is particularly important for people with risk factors to promptly consult with a medical professional if symptoms arise. Possible risk factors for thymus cancer include older age (most patients are diagnosed in their 70s) and Asian or Pacific Islander descent.

Autoimmune diseases & thymoma

Thymoma is linked to certain autoimmune diseases that are considered to be paraneoplastic syndromes, or conditions associated with cancer but not directly caused by the tumor itself.  

Autoimmune diseases are disorders that cause the body’s immune system to mistakenly attack healthy organs and tissues. Many patients with thymoma experience:

Myasthenia gravis

Between 30% and 65% of thymoma patients test positive for myasthenia gravis. This disease causes the body’s immune system to produce antibodies that prevent the chemical signals that control muscle movements. This can result in muscle weakness, reduced coordination and loss of coordination.

Red cell aplasia

About 5% of people with thymoma also have red cell aplasia, a condition that significantly inhibits the body’s ability to produce red blood cells. Reduced red blood cell production can lead to anemia and cause symptoms like dizziness, weakness, fatigue, and shortness of breath.


Hypogammaglobulinemia occurs in about 5% to 10% of thymoma patients. Characterized by unusually low amounts of important illness-fighting antibodies called gamma globulins, this disease increases the risk of infections.

Other autoimmune diseases that are sometimes associated with thymoma include:

  • Polymyositis
  • Rheumatoid arthritis
  • Sarcoidosis
  • Systemic lupus erythematosus
  • Scleroderma
  • Thyroiditis
  • Ulcerative colitis
  • Sjogren’s syndrome

Still, most people with these autoimmune diseases do not have thymoma. Individuals who experience possible symptoms of thymoma or autoimmune problems should promptly speak with a physician and be mindful of additional changes in their health. As with most other cancers, early detection of thymoma and thymic carcinoma is key to achieving a successful outcome and positive quality of life.

Our approach to thymomas & thymic carcinoma

The oncologists at Moffitt Cancer Center are skilled in recognizing the warning signs of thymoma and thymic carcinoma. Thanks to our world-class expertise and advanced diagnostic technologies, we can efficiently and correctly diagnose the underlying cause of a patient’s symptoms. In one location, our professionals perform minimally invasive biopsies and a variety of imaging techniques, including computed tomography (CT) scans, positron emission tomography (PET) scans and magnetic resonance imaging (MRI scans—all of which are commonly used to diagnose or rule out thymus cancers.

If a patient’s symptoms are the result of thymoma or thymic carcinoma, our multispecialty team will collaborate to create an individualized treatment recommendation based on the size, stage and location of the tumor, along with the patient’s treatment and supportive care preferences. The experts in our Thoracic Oncology Program focus exclusively on thoracic malignancies and possess a unique level of experience treating uncommon and complex cancers like thymoma and thymic carcinoma. Furthermore, we are the only Florida-based National Cancer Institute-designated Comprehensive Cancer Center—a distinction that speaks directly to our ambitious research efforts and trailblazing clinical trials.  

Schedule an appointment

If you are experiencing possible symptoms of thymoma or thymic carcinoma and would like to consult with a cancer specialist, schedule an appointment at Moffitt by submitting a new patient registration form online or calling 1-888-663-3488. Our oncologists evaluate and diagnose symptoms, provide second opinions and deliver leading-edge treatments for virtually all types of cancer.