[Twin pregnancy with both complete hydatiform mole and coexistent alive fetus: report of a non-antenatal diagnosed case].

Twin pregnancy with both complete hydatiform mole and coexistent fetus is a rare situation and a challenging diagnosis. We report an unusual case of twin pregnancy with complete mole diagnosed after pathological examination of the placenta. A 30-year-old woman, 14 weeks gestation, presented with vaginal bleeding. The abdominal ultrasound examination revealed an heterogeneous aspect of inferior placenta, which was interpreted as a hematoma, and, a multilacunar placental aspect with an oligoamnios respectively at initial follow-up and 22 weeks gestation. The karyotype from chorionic villi was normal (46 XY). At 25 weeks, after a spontaneous abortion, she delivered a 950g newborn who died quickly. On placental gross examination two distinct but connected masses were identified: one exhibited a normal placental aspect and the other vesicular villi with necrotic and hemorrhagic fragments. On microscopic examination, the normal placenta showed well-developed chorionic villi and the multicystic placenta showed molar villi. Immunohistochemical study and fluorescence in situ hybridization confirmed a complete hydatiform mole. No persistent gestational trophoblastic neoplasia was observed during the follow-up.