Incidental placental choriocarcinoma in a term pregnancy: a case report.

Introduction: Gestational choriocarcinoma occurs in 1 in 40,000 pregnancies. Of all forms of gestational choriocarcinoma, placental choriocarcinoma is the most rare. Maternal choriocarcinoma is usually diagnosed in symptomatic patients with metastases. The incidental finding of a choriocarcinoma confined to the placenta with no evidence of dissemination to the mother, or infant is the least common scenario.

Case Presentation: The patient is an 18 year-old Gravida 1 Para 1 African American female who delivered a viable 3641 g female infant at 39 weeks gestation. Her pregnancy course was complicated by gestational hypertension during the third trimester. Her placenta revealed intraplacental choriocarcinoma. She was then followed closely by the Gynecologic Oncology service with a weekly serum beta human chorionic gonadotropin value. Beta human chorionic gonadotropin values dropped from 3070 mIU/ml to less than 2 mIU/ml two months post partum. No chemotherapy was initiated. Metastasis was ruled out by chest x-ray and whole body computed tomography scan. To date, both mother and baby are well.

Conclusion: Due to the potential fatal outcome of placental choriocarcinoma, careful evaluation of both mother and infant after the diagnosis is made is important. The incidence of placental choriocarcinoma may actually be higher than expected since it is not routine practice to send placentas for pathological evaluation after a normal spontaneous delivery. The obstetrician, pathologist, and pediatrician should have an increased awareness of placental choriocarcinoma and its manifestations.