Mediastinal tumors are tumors inside the mediastinum, i.e. the cavity between the left and right lungs. Overseas literatures suggest that the most common anterior mediastinal tumors found are lymphoma, thymoma and germ cell tumor. Thymoma accounts for 20% of mediastinal tumor and is the most common anterior mediastinal tumor reaching approximately 50% of all tumors in adults. Ninety percent of all thymomas are located in the anterior mediastinum and some of them occur at the neck region or other mediastinal areas. Surgery still becomes the main treatment followed by adjuvant radiation for invasive thymoma. For inoperable patients, induction chemotherapy followed by a surgical reassessment post-therapy, and adjuvant radiation therapy is generally recommended, in spite of the lacking prospective studies for such treatment. Durable responses can be obtained both in the metastatic and recurrent condition, and various novel therapies are currently being studied.