Key takeaways: It is inappropriate to make an immediate decision to terminate the pregnancy in the case of placental findings similar to those of hydatidiform mole with a coexistent fetus. It is important to evaluate it carefully and consider the likelihood of PMD. If the pregnancy is to be continued, antenatal assessments should be carried out more frequently, not only due to the fetal growth restriction or late pregnancy loss but also due to the potential for very early onset of severe PE. The close monitoring of serum sFlt-1 level is recommended to be beneficial for perinatal management in this condition.

Placental mesenchymal dysplasia (PMD) is characterized by an enlarged placenta with abnormal cystic villi similar to that seen in a hydatidiform mole. PMD is a rare anomaly. In PMD, a normal fetus, along with a cystic lesion of the placenta, is observed during ultrasonography.…