Thymoma and thymic carcinoma are rare thymus gland tumors that form on the outside surface of the thymus.
The thymus is a small gland located under the breastbone. It is responsible for the development of lymphocytes, which are cells that travel through the body and help fight infection. Thymoma carcinomas are slow growing and do not spread.
Thymic carcinomas are less common, but more difficult to treat since they grow and spread very quickly. Another difference between the two is the appearance of the cells under a microscope. Thymoma carcinoma cells look very similar to regular thymus gland cells, while thymic carcinoma cells look completely different.
The cause of these tumors is not known. They affect men and women equally and usually are diagnosed around the ages of 50 – 60. There is a correlation with thymoma and thymic carcinoma and the immune system disease myasthenia gravis. Approximately 30% of the patients who develop thymoma and thymic carcinoma have myasthenia gravis.
Signs and Symptoms
Many people with thymoma and thymic carcinoma show no signs or symptoms. The tumors are often found by accident during an x-ray or scan they are having done for a completely unrelated reason. About one third of patients experience symptoms in their chest such as coughing, chest pains, difficulty breathing, and a hoarse voice.
Diagnosis
Thymoma and thymic carcinoma can be diagnosed based on an x-ray alone. If it looks unusual doctors will perform a biopsy. Thymoma and thymic carcinoma are staged based on their size, location, and whether or not they have spread, among other factors.
Stage I thymoma and thymic carcinoma have only affected the thymus gland. Stage IV tumors have spread deeper into surrounding tissues such as the heart and lungs. They have also spread to other parts of the body either via the blood or lymphatic system.
Treatment
The ideal treatment for thymoma and thymic carcinoma is complete removal of the tumor. This offers the best chance for a full recovery. Radiation is used in later stage tumors in an attempt to keep the tumor from recurring. Radiation can also be helpful in cases where the tumor could not be removed 100%.
Over the last 10 years chemotherapy has been used more frequently in treating thymoma and thymic carcinoma. A combination of chemotherapy drugs has shown to be most successful.
Prognosis
Among other things, the prognosis for thymoma and thymic carcinoma depends on the size and stage of the tumor, as well as the overall health of the patient. Patients with stage I tumors see a 95% five year survival rate. With stage IV tumors this drops to 50%.
