Germ cell tumors are one of the causes of an anterior mediastinal mass, and any of the germ cell histologies may be identified. They can therefore be divided histologically into:
Alternatively, anterior mediastinal germ cell tumors can be thought of as benign and malignant 1:
- benign
- mature teratoma
- mature teratoma with an immature component of less than 50% 1
- malignant
- all others
Mature teratomas are the most frequent histology encountered in the mediastinum (see mediastinal teratoma) and account for ~60% (range 50-70%) of all mediastinal germ cell tumors 2.
It is difficult to distinguish between the various malignant histologies, and clinical correlation with serum tumor markers (AFP, beta-HCG) and biopsy is usually required.