Placental Site Trophoblastic Tumor (PSTT) is a rare type of tumor that arises from the trophoblastic tissue, which is involved in the formation of the placenta during pregnancy. This tumor typically develops after a pregnancy, often following a normal delivery, miscarriage, or molar pregnancy. PSTT is characterized by the presence of abnormal cells that can invade surrounding tissues. PSTT is classified as a type of gestational trophoblastic disease, which includes other conditions like molar pregnancy and choriocarcinoma. Diagnosis usually involves imaging studies and blood tests to measure human chorionic gonadotropin (hCG) levels. Treatment often includes surgery to remove the tumor, and in some cases, chemotherapy may be necessary.