Stage I placental site trophoblastic tumor with complete response after pembrolizumab

•Placental site trophoblastic tumors (PSTT) express PD-L1, making them ideal targets for PD-1 and PD-L1 inhibitors.•For this PSTT patient seeking fertility-sparing treatment, PD-1 inhibition demonstrated complete and sustained response.•Despite anti PD-1 toxicity, there is potential for significant benefit when no alternative fertility-sparing options exists.