Choriocarcinoma at an Abdominal Wall Cesarean Scar: Recurrence After Multi-Line Chemotherapy and Exploration of Salvage Therapy.

Choriocarcinoma arising at an abdominal wall cesarean scar is not only exceedingly rare and diagnostically challenging but also represents a therapeutic dilemma, particularly when it becomes chemoresistant or relapses after multi-line chemotherapy. Here, we report a 40-year-old woman initially managed for suspected ectopic pregnancy with two dilation and curettage (D&C) procedures and three doses of methotrexate (MTX) therapy, but her serum β-hCG level remained persistently elevated. Further imaging examinations revealed concurrent lesions in the uterine cavity and abdominal wall cesarean scar, and subsequent surgical excision confirmed a high-risk choriocarcinoma at the scar, corresponding to a prognostic score of 10. Postoperative EMA/CO chemotherapy transiently normalized serum β-hCG levels, followed by the first recurrence. Subsequent salvage therapies (EMA/EP, re-resection, and FAV regimen) yielded only short-lived remissions, with β-hCG rebounding above 1000 mIU/mL, indicating second recurrence. Moreover, the suboptimal decline in β-hCG in response to TP/TE and FAEV regimens after the second recurrence further demonstrated the limited efficacy of chemotherapy. In addition, immunohistochemical profiling showed CD8+T cell infiltration, PD-L1 expression with a tumor proportion score of 40%, and VEGF/EGFR positivity, along with intact mismatch repair proteins. Collectively, these findings provide a rationale for the use of immune checkpoint inhibitors (ICIs), which have shown superior complete response rates in chemorefractory gestational trophoblastic neoplasia (GTN) compared with standard or high-dose chemotherapy. Notably, both the 2025 EOTTDESGOGCIGISSTD and FIGO guidelines recommend immunotherapy before high-dose chemotherapy for recurrent disease, suggesting that a personalized combination of ICIs with chemotherapy and/or anti-angiogenic agents may represent a promising salvage strategy. This case underscores the diagnostic challenge, limited durability of multi-line chemotherapy and surgery, and emerging role of immunotherapy. Early recognition, pathological confirmation, standardized chemotherapy, timely surgery, and appropriate introduction of ICIs remain key to improving outcomes in this rare entity.