Twenty per cent of anterior compartment mediastinal tumours are of germ cell origin and fall into three groups: benign teratoma, malgnant seminoma and non-seminomatous malignant germ cell tumours (see below). Most authorities no longer believe these to be metastatic from the gonads but due to primary tumours arising from residual germ cells which have migrated along the embryonic urogenital ridge. The malignant germ cell tumours, which have a preponderance in males, may also associated be with chromosomal abnormalities such as Klinefelter’s syndrome and other blood dyscrasias not related to treatment.

1. •Benign teratomas are cured by complete surgical excision.
   

2. •Seminomas are very radiosensitive and radiotherapy is the mainstay of treatment. Bulky tumours may respond to induction therapy with cisplatin, bleomycin and etoposide before radiotherapy.
   

3. •Non seminomatous tumours: cisplatin based chemotherapy can produce complete remission in over 50% of cases. Surgery is indicated for residual disease in the mediastinum or for lung metastases if serum tumour markers have reverted to normal. Where "mature" teratoma is found the patient can be observed with regular serum markers and chest radiographs. The finding of residual germ cell carcinoma salvage chemotherapy should be considered