High-intensity focused ultrasound as a bridging vascular-modulating therapy for fertility-sparing management of placental site trophoblastic tumor complicated by uterine arteriovenous fistula: a case report

BACKGROUND: Placental site trophoblastic tumor (PSTT) is a rare gestational trophoblastic neoplasm characterized by local invasiveness and marked vascularity. Surgical management may be associated with substantial bleeding risk and loss of fertility, particularly when complicated by uterine arteriovenous fistula (UAVF). High-intensity focused ultrasound (HIFU) may provide a fertility-preserving adjunctive approach in selected cases. CASE PRESENTATION: A 23-year-old woman presented with persistently plateaued serum human chorionic gonadotropin levels following hysteroscopic management for suspected incomplete abortion. Imaging revealed a deeply invasive hypervascular uterine lesion with UAVF, raising strong suspicion of gestational trophoblastic neoplasia. Given her strong desire for fertility preservation and high surgical risk, ultrasound-guided HIFU was performed as an initial vascular-modulating intervention. Subsequent expert pathological review confirmed PSTT. RESULTS: HIFU achieved significant reduction in lesion perfusion and vascular flow, as confirmed by Doppler ultrasound and contrast-enhanced MRI. Although complete tumor ablation was not achieved due to lesion size and deep invasion, subsequent low-dose chemotherapy resulted in complete biochemical remission accompanied by radiologic regression of residual lesions. No major HIFU-related complications were observed, and normal menstrual function resumed during follow-up. CONCLUSION: HIFU is a technically feasible and safe fertility-preserving adjunct for vascular modulation in hypervascular PSTT complicated by UAVF. While HIFU alone may not achieve definitive oncologic control in large or deeply invasive lesions, it can serve as a bridging strategy to reduce tumor perfusion and vascularity, facilitating subsequent systemic therapy in carefully selected patients. This approach demonstrates the potential role of HIFU as a bridging vascular-modulating strategy within multimodal fertility-preserving management.