A Rare Case of Exaggerated Placental Site Reaction.

Exaggerated placental site (EPS) reaction is a rare, poorly understood benign condition associated with persistent and excessive invasion of the uterus by intermediate trophoblasts. It often can mimic placental site trophoblastic tumor and epithelioid trophoblastic tumor. We present a 34-year-old woman with persistent elevation of human chorionic gonadotropin (hCG), who was unsuccessfully treated with chemotherapy for suspected gestational trophoblastic neoplasm. An MRI scan revealed infiltrative disease involving the uterine cervix and lower segment, following which she underwent hysterectomy. Histology was in favor of an EPS reaction, and hCG returned to a nondetectable level after surgery. This case highlights the importance of considering the possibility of EPS reaction in patients presenting with a uterine mass and persistently low levels of hCG despite chemotherapy. However, preoperative confirmation of EPS reaction could be challenging.