ABSTRACT • Growing teratoma syndrome (GTS) is defined by Logothetis et al. in 1982 as a growth of a benign tumor after removal of a primary malignant germ cell tumor during or after treatment with chemotherapy. We report the case of a twelve year-old girl with immature ovarian teratoma who underwent surgery and chemotherapy. Her tumor markers normalized by the end of chemotherapy. However, she developed months later retroperitoneal masses that were subsequently and repeatedly resected. Histopathology revealed each time mature teratoma consistent with the diagnosis of GTS.

Keywords : ovary; immature teratoma; growing teratoma syndrome; chemotherapy; tumor markers; recurrence