1. Unlike the HYDATIDIFORM MOLE, Choriocarcinoma contains no CHORIONIC VILLI but rather sheets of undifferentiated cytotrophoblasts and syncytiotrophoblasts (TROPHOBLASTS)

2. The Chorionic plate of the placenta is formed by the proliferation of cytotrophoblasts and degeneration with deposition of fibrin-type fibrinoid

3. The Chorion leave is composed by the inner Chorionic mesoderm similar to the mesenchymal region of the amnion and an outer highly variable trophoblastic layer with extravillous cytotrophoblast cells that represent the only residues of the former villi of the Chorion frondosum .