Growing teratoma syndrome is an increase of tumor size containing only a mature teratoma component, during or after chemotherapy for germ cell tumors. Mature teratomatous elements are chemoresistant and have to be resected surgically. We describe three patients with malignant immature teratoma treated with chemotherapy and surgical resection. All three had an increase in the size of the mass after chemotherapy, surgery was possible, and histology revealed mature teratoma. One of the patients showed fluorodeoxy glucose positron emission tomography (FDG-PET) positivity for growing teratoma syndrome, but the histology revealed only mature teratoma. All three patients are alive, at 55, 72, and 103 months' follow up after the initial diagnosis. Data collected from the literature are reviewed. Early recognition of this syndrome is essential as it offers hope for curative resection and avoids the use of ineffective chemotherapy.