Placental site trophoblastic tumor with sole metastasis to breast: A case report.

Placental site trophoblastic tumor (PSTT) is a rare form of gestational trophoblastic neoplasia (GTN). It most commonly occurs after a delivery but may arise after any type of pregnancy. PSTT arises after neoplastic transformation of intermediate trophoblastic cells. The most commonly reported symptoms are abnormal bleeding or amenorrhea. Due to the rarity of this disease, evidence on prognostic factors as well as optimal treatment is limited. While treatment for early-stage disease is usually limited to surgery, multimodal treatment with chemotherapy and surgery may be important for metastatic disease. Metastatic disease may be associated with minimal elevations of human chorionic gonadotropin (hCG). Here we present an unusual case of a patient with PSTT and an isolated breast metastasis who was successfully treated with surgical resection and single-agent chemotherapy.