Thymomas and thymic carcinomas are rare type of tumours that start from epithelial cells in the thymus- a gland located behind the breast bone in the mediastinum. Mediastinum is responsible for the development of many immunologic functions in early life.
Thymomas are (slightly) more common in men than in women and occur to people in between age 40 and 60. What causes thymoma or what are its risk factors, is not known which makes it difficult to prevent it.
Half of the thymomas do not show any signs and symptoms and are diagnosed only wneh a person gets tested for some other medical condition. If symptoms do occur in a person, he/she may feel chest pain, shortness of breath, and cough.
A person who suffers thymoma may also develop myasthenia gravis (an autoimmune neuromuscular disease leading to fluctuating muscle weakness and fatigue.) and paraneoplastic syndrome (a disease or symptom that is the consequence of cancer in the body but, unlike mass effect, is not due to the local presence of cancer cells).
Other associated conditions include other autoimmune diseases including pure red cell aplasia (underdevelopment of precursors for red blood cells in the bone marrow).
The tumour 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.
Thymoma is a tumour of the thymus, an organ that is part of the lymphatic system and is located in the chest, behind the breastbone. It may or may not be cancerous. On the other hand, thymic carcinoma, also called type C thymoma is a rare type of thymus gland cancer. It usually spreads, has a high risk of recurrence, and has a poor survival rate. Thymic carcinoma is divided into subtypes, depending on the types of cells in which the cancer began.
Other cancers and tumours can occur in the mediastinum. Cancers can start in the oesophagus (oesophageal cancer), in the heart (and the tissue surrounding it), in the trachea, and in the lymph nodes (lymphoma). Rarely, cancers and tumours known as germ cell tumours can also start in the mediastinum. These come from cells like those found in the testicles and ovaries.
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