Primary mediastinal germ cell tumors: the clinicopathologic analysis of 56 cases / 临床与实验病理学杂志

ABSTRACT

Purpose To investigate the clinicopathologic features of primary mediastinal germ cell tumors and to improve the diagnosis and treatment guidance. Methods The clinical features, histologic findings, molecular detection and biological behaviors of 56 PMGCT cases were analyzed retrospectively. Results The age of patients ranged from 9 to 48 years (median age 29.1 years), and mature teratoma(76.8％, 43/56) were the most common type.3 cases of mature teratoma were prepubertal patients.53 cases of postpubertal patients included 40 cases of mature teratoma, 2 cases of nonmature teratoma, 2 cases of yolk sac tumor, 5 cases of seminoma, 4 cases of mixed germ cell tumor. All malignant PMGCTs were male, and mature teratoma was found in the female. Histopathologic morphology and immune phenotype of primary mediastinal germ cell tumors were consistent with those of sexual gland. The isochromosome 12p was detected in various component of malignant GCTs, not in mature teratoma. All patients underwent surgical resection, with additional chemotherapy for malignant germ cell tumor cases. The prognosis of mature teratoma regardless of prepubertal or postpubertal patients was benign, but PMGCTs (except mature teratoma) of postpubertal type were malignant. Conclusion Primary mediastinal germ cell tumors are rare and mature teratoma is most common. The malignant PMGCTs mostly occur in young men. The abnormal 12p detected by FISH is helpful to differential diagnosis and guide the treatment.