Mediastinal germ cell tumors.

Mediastinal germ cell tumors are uncommon tumors that occur predominantly within the anterior mediastinum and frequently present as a very large mass with local compression. Symptoms are typically vague and represent the local mass effects of the tumor. Chest computed tomography and examination of serum tumor markers provide the critical workup before a tissue diagnosis is obtained. Seminomas are extremely sensitive to both chemotherapy and radiation and are primarily treated nonsurgically. Benign teratomas without malignant elements are extremely resistant to both chemotherapy and radiation and are treated exclusively with surgical resection with excellent outcomes. Malignant nonseminomatous germ cell tumors are primarily treated with chemotherapy, with adjuvant surgery reserved for patients with residual mediastinal masses after systemic therapy.