Extra-Gonadal Germ Cell Tumors

Abstract

Extragonadal germ cell tumors (EGCTs) are rare tumors that predominantly affect young males. They are located in the body midline. The most common sites of EGCTs are the mediastinum (50-70%), the retroperitoneum (25-40%), the pineal gland (5%), and the sacrococcygeal area (less than 5%). 2-5% of germ cell tumors are considered of extragonadal origin. The anatomical distribution of EGCTs might be explained by the migration of primordial germ cells from the yolk sac along the hindgut and its mesentery to the genital ridges. EGCTs are considered to develop from pluripotent embryonal stem cells that because of conditions in the midline of the embryo have undergone germ cell differentiation. Presentation of EGCTs is often in an advanced local stage and with distant metastases. At diagnosis a testicular primary tumor should by all means be excluded. There is strong evidence that a considerable amount of EGCTs, especially retroperitoneal EGCTs have in fact a regressed primary testicular tumor. Treatment is based on localization, histology and extent of disease. Chemotherapy is often first line treatment. Surgery is advocated for teratomas and residual disease.