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< Lung and Esophageal Cancers


About Thymoma

Thymoma and thymic carcinoma are diseases in which malignant (cancer) cells form on the outside surface of the thymus.

The thymus, a small organ that lies in the upper chest under the breastbone, is part of the lymph system. It makes white blood cells, called lymphocytes, that protect the body against infections.

There are different types of tumors of the thymus. Thymomas and thymic carcinomas are rare tumors of the cells that are on the outside surface of the thymus. The tumor cells in a thymoma look similar to the normal cells of the thymus, grow slowly, and rarely spread beyond the thymus. On the other hand, the tumor cells in a thymic carcinoma look very different from the normal cells of the thymus, grow more quickly, and have usually spread to other parts of the body when the cancer is found. Thymic carcinoma is more difficult to treat than thymoma.


Signs and symptoms of thymoma and thymic carcinoma include a cough and chest pain.

However, thymoma and thymic carcinoma may not cause any early signs or symptoms. The cancer may be found during a routine chest X-ray. Signs and symptoms may be caused by thymoma, thymic carcinoma or other conditions. Check with your doctor if you have any of the following:

  • A cough that doesn't go away
  • Chest pain
  • Trouble breathing

Risk Factors

Thymoma is linked with myasthenia gravis and other autoimmune diseases.

People with thymoma often have autoimmune diseases as well. These diseases cause the immune system to attack healthy tissue and organs. They include:

  • Acquired pure red cell aplasia
  • Hypogammaglobulinemia
  • Lupus erythematosus
  • Myasthenia gravis
  • Polymyositis
  • Rheumatoid arthritis
  • Sj√∂gren syndrome
  • Thyroiditis