Placental Mesenchymal Dysplasia – a case report

Placental mesenchymal dysplasia (PMD) is a very rare vascular placenta anomaly, characterized by an enlarged placenta with grape-like vesicles. Initially, the disease can be mistaken for a molar pregnancy on ultrasound, but the condition is not a trophoblastic disorder, and presents with unique diagnostic and clinical features. Genetically, there is an association with androgenic/biparental mosaicism which can be confined to the placenta but also can be present in the fetus, and there is an increased risk of imprinting disorders such as Beckwith-Wiedemann syndrome. Obstetrically, PMD is associated with fetal growth restriction, preeclampsia, preterm delivery, and increased risk of intrauterine fetal demise. Thus, PMD is often associated with severe maternal and/or fetal complications, and this case illustrates the challenge in the diagnosis and prenatal counseling.