Teratoid tumors of the mediastinum.

Anterior mediastinum is the third commonest location for teratoid tumors besides the ovaries and the testes. Although there is still some confusion about the classification of these tumors, most authors now agree that the term dermoid cyst should be used for cystic lesions containing ectodermal and mesodermal elements. Teratoma should be reserved for solid or cystic lesions containing derivatives of all the three germ layers. The clinical manifestations offer no clue to their malignant potentiality. Chest roentgenogram, tomogram and esophagogram are useful, and aortic arch studies may be indicated in some cases to exclude aortic aneurysms. Surgical excision offers the best method of diagnosis and treatment. The prognosis is excellent for benign teratoids but poor for malignant teratoids, especially in children and young adults.