Malignant germ cell tumors of the mediastinum.

A review of 56 cases of primary malignant germ cell tumors of the mediastinum revealed that, as with benign teratomas, the tumors occurred in young adults (mean age 29 years) but that the sex distribution differed (86% male and 14% female). A single germ cell element was found in 37 (66%) of the tumors, and various combinations were present in the remaining 19 (34%). The tumors were classified among five recognized types of germ cell tissues. There were 24 seminomas (22 pure and two with mature teratomas), 17 embryonal carcinomas (nine pure and eight with mixtures), five teratomas, seven choriocarcinomas (three pure and four with mixtures), and three pure yolk sac tumors. Most (86%) of the patients were symptomatic at the initial examination, with chest pain, cough, and loss of weight being the most frequent presenting symptoms. The standard posteroanterior and lateral roentgenograms were the most helpful diagnostic tool, showing evidence of an anterior mediastinal mass in 53 patients. The diagnosis was established by surgical exploration of the mediastinum or by biopsy of a lymph node in 55 patients. Of the 55, 24 (43.6%) had complete resection of the tumor and 31 (56.4%) had incomplete resection or biopsy alone. The overall prognosis for mediastinal germ cell tumors is poor, partly because the tumors are far advanced at the time of diagnosis but also because some of the tumors that contain embryonal cell carcinoma, choriocarcinoma, and yolk sac elements are very aggressive. Factors that were prognostic in patients with seminoma--such as age, presence of the superior vena caval syndrome, lymphadenopathy, evidence of hilar disease on the chest roentgenogram, and resectability--were not predictive in patients with other types of malignant germ cell tumors. Although aggressive combination chemotherapy may represent a significant treatment modality for nonseminomatous mediastinal tumors, the present study spanned many years in which no chemotherapy was available. Patients in the later years of the study received combination chemotherapy with various treatment regimens. No conclusions concerning specific chemotherapy, therefore, can be derived from this study.