Exaggerated placental site in a cesarean scar: Misdiagnosed as gestational trophoblastic neoplasia: A case report.

The present study reports a rare case of an exaggerated placental site (EPS) in a caesarean scar that was misdiagnosed as gestational trophoblastic neoplasia (GTN) by imaging, resulting in unnecessary surgical treatment. A 38-year-old woman underwent hysteroscopic resection of a cesarean scar pregnancy (CSP). The patient's serum β-human chorionic gonadotropin (β-hCG) level was elevated (76,196 mIU/ml) at the 24-day postoperative follow-up visit. On postoperative day 51, the patient experienced vaginal bleeding for three days and β-hCG levels were 2,799 mIU/ml. Ultrasonography and MRI revealed a heterogeneous mass and hypervascularity. The patient was diagnosed with a GTN in a cesarean scar and treated with methotrexate (MTX). β-hCG levels decreased after 3 MTX doses, but the mass did not change in size and was still hypervascular on imaging. Total hysterectomy was performed due to the serious side effects of chemotherapy and the lack of desire to preserve fertility. The histological findings supported the diagnosis of an EPS reaction. The present case is unique because of the rare intrauterine mass and possibility of retained trophoblastic changes causing EPS. EPS differs from GTN both clinically and pathologically and should be considered a possible diagnosis in any woman who has irregular bleeding following CSP resection.