Most mediastinal malignant tumors are large and cause symptoms by compressing or invading adjacent structures, including the lungs, pleura, pericardium, and chest wall.
Rare cases of adult onset acute megakaryoblastic leukemia are associated with malignant mediastinal germ cell tumor.
In addition to physical examination and routine laboratory studies, initial evaluation should include CT of the chest and abdomen, and determination of serum levels of HCG and alpha-fetoprotein.
Initial treatment with four courses of bleomycin, etoposide, and cisplatin, followed by surgical resection of any residual disease, is considered standard therapy.
Mediastinal and other extragonadal germ cell tumors were initially thought to represent isolated metastases from an inapparent gonadal primary site.