The large placental chorioangioma is a non-trophoblastic vascular tumor of placenta which size is more than 4 cm. It's a rare tumor, the incidence is between 1/3500 and 1/9000 birth. We analyze, on base of our case and from a literature review, the ultrasonography aspects of this tumor: we bring out also the physiological mechanisms of maternal and fetal complications and finally we detail the therapeutic possibilities. Chorioangioma appears in ultrasound scan like a thoroughly limited hypo-echogenic zone The vascular origin of the tumor can be confirmed by color Doppler. A left-right shunt effect results from arterio-venous communications and causes backwardness growth and fetal death in-utero The fetus is exposed to anemia and microangiopathic thrombopenia The maternal complications are: hydramnios, abruption placenta, premature ruptured membrane. Therapeutic possibilities are reduced: In several fetal anemia, blood transfusion can be done. Some techniques for tumor devascularization are be tried by someone.