Mediastinal Germ Cell Tumors

Abstract

Mediastinal germ cell tumors are a rare malignant process, but one of the most common tumors found in the anterior mediastinum. Mediastinal seminoma has the same radiosensitivity as the testes primary. Localized mediastinal seminoma may be successfully treated with radiotherapy alone, with excellent cure rates. Patients with bulky tumors will often have residual radiographic abnormalities. Retrospective studies have provided evidence that close observation without surgical intervention may be a viable option. Patients with extra-mediastinal spread require systemic cisplatin-based chemotherapy. In contrast, all patients with nonseminomatous mediastinal germ cell tumors require systemic chemotherapy with cisplatin-based chemotherapy as the initial approach. These patients require resection of any persistent postchemotherapy radiographic abnormalities. Mediastinal germ cell tumors are also associated with a variety of unusual clinical conditions. The first recognized association was the increased incidence of mediastinal germ cell tumors with Klinefelter's syndrome. As experience with the histopathology of mediastinal germ cell tumors increased, several unusual variants were recognized, such as embryonal rhabdosarcoma, small cell undifferentiated carcinoma, adenocarcinoma, and neuroblastoma. Lastly, a unique association with mediastinal germ cell tumors and acute megakaryocytic leukemia was noted that was not related to prior chemotherapy. In summary, mediastinal germ cell tumors are numerically rare, but one of the most common tumors in the anterior mediastinum with unique biologic and clinical properties. This tumor should be considered strongly in the differential diagnosis of anterior mediastinal masses.

Key Words:

germ cell tumor - mediastinum - chemotherapy