Thymoma and Thymic Carcinoma

What is Thymus?

The thymus is located in the chest cavity region that encloses the heart, trachea, and esophagus. The thymus lies above the main vein (superior vena cava) and the aorta of the heart. It is an important organ for our body’s defense because the differentiation of immune T-cells (T-lymphocytes) occurs in the thymus during the entire life span of an individual. The thymus consists of the cortex and the medulla. The medulla is mainly made up of epithelial cells while the cortex is the seat of the lymphocytes. Epithelial cells are crucial in the maturation of immune T-cells.

What is Thymoma and Thymic Carcinoma?

Thymoma and thymic carcinoma are rare cancers that develop from the epithelial cells of the thymus. The rarity of these cancers is underlined by the statistic that lower than 1 percent of individuals are affected with thymomas or thymic carcinomas. Thymomas grow slowly on the outer surface of the thymus and are more common of the two types of thymic cancer. However, thymomas rarely (one-third of total thymomas) spread to other parts of the body. Depending on the type (spindle shaped [A] or epithelioid shaped [B]) of epithelial cells, thymomas may be classified according to the World Health Organization (WHO) guidelines into types A, AB, B1, B2, and B3. Thymomas are most often observed in adults above the age of 40 years. Children are not generally affected.

Thymic carcinomas develop in a similar manner as thymomas due to cancer of epithelial cells. They are classified as type C. These cancers grow faster than thymomas, are more aggressive, and may spread to other parts of the body, or to the lining of the lungs. It is a complicated condition to treat since surgery does not reduce the frequency of relapse.

Children may occasionally be diagnosed with the condition. Normally, adults over the ages of 50 and 60 years are diagnosed with thymomas or thymic carcinomas. These tumors make up 1 percent of all tumors in adults.