Germ cell is ovarian malignancy that occurs in a woman, especially at the young age women. Immature teratoma is the second most common malignancy in cases of germ cell. Immature teratoma has a good cure rate after proper treatment, namely surgery and chemotherapy. Growing teratoma syndrome (GTS) is a rare condition among patients with immature teratoma which is characterized by enlargement or appearance of a new mass after adequate systemic chemotherapy, normal tumor serum markers, and mass histopathology results show the appearance of mature teratoma in the new mass.