AbstractIntroductionMalignant germ cell tumors (MGCTs) can develop either extracranially or intracranially. Growing teratoma syndrome (GTS) may develop in these patients following chemotherapy. Reports on the clinical characteristics and outcomes of GTS in children with MGCTs are limited.MethodsWe retrospectively collected the data, including the clinical characteristics and outcomes of five patients in our series and 93 pediatric patients selected through a literature review of MGCTs. This study aimed to analyze survival outcomes and risk factors for subsequent events in pediatric patients with MGCTs developing GTS.ResultsThe sex ratio was 1.09 (male/female). In total, 52 patients (53.1%) had intracranial MGCTs. Compared with patients with extracranial GCTs, those with intracranial GCTs were younger, predominantly boys, had shorter intervals between MGCT and GTS, and had GTS mostly occurring over the initial site (allp< 0.001). Ninety‐five patients (96.9%) were alive. However, GTS recurrence (n= 14), GTS progression (n= 9), and MGCT recurrence (n= 19) caused a substantial decrease in event‐free survival (EFS). Multivariate analyses showed that the only significant risk factors for these events were incomplete GTS resection and different locations of GCT and GTS. Patients without any risk had a 5‐year EFS of 78.8% ± 7.8%, whereas those with either risk had 41.7% ± 10.2% (p< 0.001).ConclusionFor patients with high‐risk features, every effort should be made to closely monitor, completely remove, and pathologically prove any newly developed mass to guide relevant treatment. Further studies incorporating the risk factors into treatment strategies may be required to optimize adjuvant therapy.