Placental mesenchymal dysplasia: a potential misdiagnosed entity

Placental mesenchymal dysplasia is a rare condition characterized by enlarged multicystic placenta with anechoic regions on ultrasound. Gross examination shows grapelike vesicles which mimics molar pregnancy. Microscopic findings shows large edematous villi with cistern formation interspersed with normal villi. The absence of trophoblastic proliferation and trophobastic inclusions differentiates it from molar pregnancy. We report a new case of placental mesenchymal dysplasia. A 31-year-old G2P1 presented with preterm vaginal bleeding at 24 5/7 weeks of gestation. Ultrasound findings show cystic placenta and placenta previa. She went into preterm labor and delivered a female baby with no dysmorphic features but later suffered from complications of prematurity. Pathologically, the placenta showed multiple grapelike cystic vesicles with unremarkable chorionic vessels. Microscopically, enlarged edematous villi with cistern formation were noted. Trophoblastic proliferation or inclusions were not seen.