Résumé
The yolk sac tumor is one of the most common malignant germ cell tumors in young children and typically occurs in the gonads. We report 6 cases of children less than 30 months old with extragonadal atypical locations of yolk sac tumor. These rare diagnoses were established by raised serum alpha-fetoprotein levels and biopsies. These patients were treated according to the French TGM 95 trial. All the patients are alive disease-free after >= 2.5 years of follow-up. We want to highlight the importance of measuring the alpha-fetoprotein levels in very young children presenting with any midline tumor, even if the tumor is not located in the typical extragonadal sites such as the sacrococcyx, mediastinum, retroperitoneum, or vagina.