A twin pregnancy with a hydatidiform mole and a coexisting live fetus: prenatal diagnosis, treatment, and follow-up.

Twin molar pregnancy with a hydatidiform mole and a coexisting live fetus is a rare form of gestational trophoblastic disease associated with an increased risk of obstetric complications and poor perinatal outcome. Prenatal diagnosis is essential for couple counseling and follow-up in Tertiary Reference Centers. Magnetic resonance imaging is important for the diagnostic differentiation of placental mesenchymal dysplasia and exclusion of myometrial invasion. Here we present a case of twin molar pregnancy with a hydatidiform mole and a coexisting live fetus diagnosed at gestational week 14 using two-dimensional (2D) and three-dimensional (3D) ultrasound and magnetic resonance imaging. We also describe the obstetric management and postmolar follow-up.