A Pathologist's Dilemma: Placental Site Tumor and Its Differential Diagnosis

Placental site trophoblastic tumor (PSTT) is a rare neoplasm originating from intermediate trophoblastic cells at the site of placental implantation. Its diagnosis poses significant challenges, particularly in distinguishing it from other gestational trophoblastic tumors, such as epithelioid trophoblastic tumors, choriocarcinoma, and placental site nodules, as well as the benign exaggerated placental site. We present a case of a 29-year-old woman with persistent gestational trophoblastic disease following a complete hydatidiform mole. A detailed review of the differential diagnoses is provided in tables to aid in the diagnostic process, allowing for a clearer comparison and better understanding of these conditions. This report highlights the importance of accurately identifying PSTT by eliminating potential differential diagnoses through careful pathological and clinical evaluation. We aim to assist pathologists and clinicians in recognizing this rare condition to ensure timely and appropriate management.