Introduction: Infantile fibrosarcoma (IFS) usually arises in the extremities during the first 12 months of life and responds well to surgery. It is unusual in the oropharynx or the prenatal period. Case report: A giant solid mass was first detected in the oropharynx and anterior neck at 24 weeks of gestation by ultrasound and fetal MRI. An EXIT procedure with intrapartum intubation with appropriate supportive therapy was successful. The diagnosis of IFS was made postpartum, and the lesion responded to neoadjuvant chemotherapy. Conclusion: IFS may arise as early as 24 weeks of gestation. In this case, an EXIT procedure allowed postpartum diagnosis with subsequent treatment.
Keywords: ETV6-NTRK3 gene fusion; fetal oropharyngeal tumor; infantile fibrosarcoma; soft tissue tumor.