Mediastinal seminomas.

A series of malignant seminomas of the mediastinum is presented and compared with previously reported series. The difficulty of conclusively excluding occult primary gonadal disease is noted. Primary mediastinal seminomas are associated with a better prognosis than teratomas of this site, mainly because of their radiosensitivity. A case report of a patient with mediastinal seminoma and two congenital abnormalities (ventricular septal defect and congenital absence of a thoracic hemivertebra) is presented and its relationship to the possible origin of these tumors discussed.