Thymoma and Thymic Carcinoma

(Also Called 'Malignant Thymoma', 'Thymus Cancer')

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.

Having a disease called myasthenia gravis can affect the risk of developing thymoma.

People with thymoma often have other diseases as well. These diseases may include myasthenia gravis, polymyositis, lupus erythematosus, rheumatoid arthritis, thyroiditis, Sjögren syndrome, and hypogammaglobulinemia.

Possible signs of thymoma and thymic carcinoma include a cough and chest pain.

Sometimes thymoma and thymic carcinoma do not cause symptoms. The cancer may be found during a routine chest x-ray. The following symptoms may be caused by thymoma, thymic carcinoma, or other conditions. A doctor should be consulted if any of the following problems occur:

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