[Primary mediastinal germ cell tumors].

The most frequent site of extragonadal germ cell tumors is the mediastinum. The majority (80%) of mediastinal germ cell tumors are benign mature teratomas, which can be easily removed. Malignant germ cell tumors account for approximately 20% of all cases and are clinically classified into seminoma and non-seminomatous germ cell tumors. Seminomas are radiosensitive and have relatively a good prognosis. Patients with non-seminomatous germ cell tumors had a very poor prognosis, however, the introduction of cis-platinum based chemotherapy has improved the prognosis of patients with these tumors. Three hundred twenty nine cases of malignant mediastinal germ cell tumors have been described in the literature and reports up to 1988 in Japan. The types and cases are following: [table: see text] Multi-drug chemotherapy with cis-platinum has improved the prognosis of patients with embryonal carcinoma and yolk sac tumors, although patients with choriocarcinoma have yet a poor response to the combination chemotherapy. Five year survivors have consisted of 19 patients with seminomas and five patients with non-seminomatous germ cell tumors. Most long survival patients have undergone surgical resection of tumors. The results suggested that the improvement for prognosis requires earlier prognosis and complete surgical removal of tumors associated with chemotherapy combining further effective regimens.