Introduction

Placental and fetal malignancies are rare complications during pregnancy but when they occur they may present a significant challenge for the perinatology team. The main differences between placental and fetal cancers are at the levels of incidence, antenatal differential diagnosis and management, and potential effect on the mother during pregnancy or after delivery. Owing to their rarity, there is limited information on the epidemiology of these unusual lesions but placental malignancies are more commonly reported in the medical literature than fetal cancer, although they are less often diagnosed antenatally. Some types of placental malignancy, such as intraplacental choriocarcinoma, are associated with a high morbidity and mortality for both the mother and baby. Furthermore, placental cancer may continue to proliferate after delivery inside the uterus or in other organs, whereas fetal cancers are now often diagnosed before delivery and they only exceptionally spread beyond the placental barrier and thus are of little or no direct medical consequence to the mother. This chapter reviews these unusual entities and focuses on the role of noninvasive investigation in their antenatal diagnosis, antenatal follow-up and management of affected pregnancies.

Placental malignancies

The group of placental malignant tumours includes mainly gestational trophoblastic neoplasia (GTN) involving the proliferation of one or more trophoblast cell types. Depending on their origin and anatomical characteristics, these tumours have different fetal and maternal consequences during pregnancy and after delivery. Thus an early and accurate antenatal diagnosis is important for patient counselling and perinatal management.