Abstract:

Objective To investigate the clinicopathological features of primary mediastinal germ cell tumors (PMGCTs). Methods A total of 46 patients with PMGCTs were selected and their clinicopathological features were retrospectively analyzed. Results Among 46 patients with PMGCTs, 24 of them were male and 22 of them were females and the median age was 29.1. All 22 female patients were diagnosed with mature teratoma. All patients with malignant GCTs were male. Main clinical manifestations were chest pain, cough, dyspnea, and fever. Among 46 patients, there were 34 patients with mature teratoma (73.9%), 4 patients with seminoma (8.7%), 3 patients with york sac tumor (6.5%), 2 patients with immature teratoma (4.3%), 2 patients with mixed GCTs (4.3%), and 1 patient with malignant teratoma (2.2%). Immunohistochemical markers PLAP, OCT3/4, CD117, CK, CD30 and LCA were helpful for accurate diagnosis and differential diagnosis of PMGCTs. Follow-ups showed that the 5-year overall survival rates of patients with mature teratoma and seminoma were 100% and 75%, respectively. The prognosis of malignant teratoma, york sac tumor, and mixed GCTs was poor. Conclusion The gender of patients with PMGCTs is closely correlated with histological types of PMGCTs. Mature teratoma is the most common type. Seminoma and york sac tumor are common types of malignant GCTs. Compared with malignant GCTs other than seminoma, the prognosis of seminoma is much better, which may be relevant to being sensitive to radiotherapy and chemiotherapy.

Key words: primary mediastinal germ cell tumors, germ cell tumors, extragonadal, immunohistochemistry