Summarize:

Thymomas are rated on a scale from stage I to stage IV, with stage I being a thymoma that is caught early on. The treatment your doctor will first recommend will be based on the stage of the thymoma.  Stage I is generally dealt with using corticosteroids and surgical intervention. Stage II is generally dealt with through surgical resection and occasionally radiation therapy. Stage III is generally dealt with through chemotherapy followed by surgical resection. Stage IV is generally dealt with through chemotherapy or chemoradiation. Corticosteroids like hydrocortisone and prednisone may be able to treat early stage thymoma. These drugs control inflammation and can be taken either orally or intravenously.  Your doctor may prescribe between 20 to 800 milligrams (mg) taken every one or two days. Intravenous corticosteroids are generally prescribed at 5 to 500 mg, depending on the severity of the thymoma. Hormone therapy is a treatment that involves the removal of hormones or blocks their involvement in the growth of the thymoma. This therapy may also be able to stop the growth of cancerous cells. This therapy is generally used in conjunction with corticosteroid medications for thymomas that are caught early on. There are two reasons that surgery may be performed when you have a thymoma. The first is to test the thymoma and see what stage it is in, and whether it is malignant or benign. The other reason is that in some cases, the thymoma can be removed through surgical excision. One type of surgical resection that is used to combat thymoma is sternotomy. This procedure involves splitting the breastbone so that the surgeon can access the anterior chest cavity and remove the thymoma, as well as the entirety of the thymus if need be. A non-metastasizing thymoma means that the thymoma is not spreading to other parts of your body. This procedure involves removing the thymus gland so that the thymoma cannot do further damage to your body. The thymus gland helps your immune system to form when you are born. When it is removed later on, the removal will have very little effect on your immune system.
Understand that the type of treatment will depend on the stage the thymoma is in. Take corticosteroids. Try hormone therapy. Consider the benefits of surgery. Talk to your doctor about sternotomy. Get a thymectomy done if you have a non-metastasizing thymoma.