Mediastinal Germ Cell Tumor

Germ cell tumors (GCT) are common in ovaries and testes. They are the most frequent tumors in the adolescent/young adult age group, with less than 2% being diagnosed above 55–60 years of age. Extragonadal GCT usually occurs in the midline of the body, such as the mediastinum, central nervous system, retroperitoneum, and sacrococcygeal region. Mediastinum is the most common location of extragonadal GCT. Primary mediastinal GCT (PMGCT) accounts for 15% of anterior mediastinal tumors in adults, constituting 1–3% of all germ cell malignancies. The pathological types include teratoma, seminoma (corresponding to testicular seminoma, ovarian dysgerminoma, and GCT of the central nervous system), yolk sac tumor (endodermal sinus tumor), embryonal carcinoma, choriocarcinoma, and mixed GCT. Teratoma is relatively common, which can be divided into benign and malignant, while non-teratogenic GCTs are malignant and clinically rare.