Thymoma is a cancer that originates from the epithelial cells of the thymus (the thymus is a tiny gland lying beneath the breastbone and is a component of the lymph system. The gland manufactures lymphocytes, which travel through the body and battle infection. It is a rare tumor, usually known for its connection with the neuro-muscular disorder myasthenia gravis. The cancer is known to develop in 15 % of patients who have myasthenia gravis Thymomas can be removed surgically and the outcome of the case is moderate to poor.
The definite cause of a thymoma has not yet known; all the same, the condition has been linked to quite a few systemic syndromes. Around 30 – 40 % individuals who have a thymoma have symptoms that are indicative of myasthenia gravis. 5 % of patients who have the cancer have other medical conditions, like, Cushing syndrome, Sjogren's syndrome, thyroiditis, red cell aplasia, polymyositis, systemic lupus erythematous, and dermatomyositis.
Those having a thymoma, habitually have other disorders of the immune system, most commonly myasthenia gravis; which is a chronic illness which weakens the muscles and results in an increased susceptibility for viral and/or fungal infections. Clinical manifestations that are associated with a thymoma are:
• A constant cough
• Pain in the chest
• Breathlessness or shortness of breath
• Muscular weakness
• Diplopia or double vision
• Drooping of the eyelids
• Swelling of the arm or face
• Difficulty in swallowing
• Anemia and its manifestations
• Increased vulnerability to various infections
• Exhaustion and tiredness
CT scans and biopsies are carried out to ascertain the location, size and degree of spread of the tumor. On the basis of the investigations and the staging of the tumor, the treatment plan is decided.
Surgery is the primary aspect of the treatment plan for a thymoma. If the mass is too big and highly invasive, pre-operative chemotherapy is given in order to shrink the size of the cancer mass and make the excision easier. In the initial stages of the cancer, only surgery is carried out to excise the mass and the surrounding tissues. Excision of the thymus does not result in any immune insufficiency, in adults. Conversely, in children, post-operative immunity is relatively abnormal and vaccinations ought to be given. Invasive cancers need supplementary treatment with radiation therapy and chemotherapy
Prognosis of a thymoma is largely dependent up on the degree of spread of the mass and when the diagnosis s made. The outcome is somewhat poor for stages III or IV as compared to stages I and II. Invasive thymomas tend to metastasize, typically to the bones, pleura, liver and brain in about 7 % cases. Stages III and IV may survive for a few years with suitable management. However, deaths have also been reported.