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 specific cells called trophoblasts, which can invade surrounding tissues. PSTT is usually diagnosed through imaging studies and biopsy. Symptoms may include abnormal vaginal bleeding or an enlarged uterus. Treatment often involves surgical removal of the tumor, and in some cases, chemotherapy may be necessary. Early detection is important for better outcomes.