Placental mesenchymal dysplasia (PMD) is a rare, benign condition that is characterized by enlargement of the placenta with multiple bunches of grape-like vesicles that can resemble a molar pregnancy by ultrasound and gross pathologic examination.
This is an often underdiagnosed and underreported case due to lack of awareness. It has been documented to be more in female fetuses with an F:M of ~3.5:1.
Clinical presentation is diverse and non-specific
- uneventful pregnancy with postnatal pathologic findings of PMD
- incidental ultrasonographic abnormalities of the placenta
- elevated maternal serum alpha-fetoprotein concentrations
- fetal growth restriction
- fetal demise
- vaginal bleeding
- preterm delivery
- fetal anomalies (e.g. fetal liver cysts or vascular malformations)
- fetal overgrowth with Beckwith-Wiedemann syndrome (BWS) features (placentomegaly, omphalocoele, macroglossia and visceromegaly)
The placenta is thickened with multiple cystic or hypoechoic areas. Doppler findings are variable. There are many documented cases of no vascularity within the lesion and further development of vascularity within. These changes could be due to progressive dilatation of chorionic arteries and veins that become aneurysmal.
One study showed that MRI could help differentiate between complete hydatidiform mole with coexistent fetus (CHMCF) by demonstrating PMD within the placenta and CHMCF within an extra fetal sac 4.
Treatment and prognosis
History and etymology
It was first described in 1991 by Moscoso et al.
Possible differential considerations include
- partial molar pregnancy
- hydropic degeneration of the placenta
- complete hydatidiform mole with coexistant fetus (CHMCF)
- subchorionic hematoma
- placental infarcts
- spontaneous abortion with hydropic changes
- 1. Ulker V, Aslan H, Gedikbasi A et-al. Placental mesenchymal dysplasia: a rare clinicopathologic entity confused with molar pregnancy. J Obstet Gynaecol. 2013;33 (3): 246-9. doi:10.3109/01443615.2012.745491 - Pubmed citation
- 2. Sudano MC, D'Emidio L, Mangiafico L et-al. Placental mesenchymal dysplasia, a case of intrauterine sudden death in a normal-sized fetus. J Prenat Med. 2013;7 (1): 9-11. Free text at pubmed - Pubmed citation
- 3. Vaisbuch E, Romero R, Kusanovic JP et-al. Three-dimensional sonography of placental mesenchymal dysplasia and its differential diagnosis. J Ultrasound Med. 2009;28 (3): 359-68. Free text at pubmed - Pubmed citation
- 4. Himoto Y, Kido A, Minamiguchi S et-al. Prenatal differential diagnosis of complete hydatidiform mole with a twin live fetus and placental mesenchymal dysplasia by magnetic resonance imaging. J. Obstet. Gynaecol. Res. 2014;40 (7): 1894-900. doi:10.1111/jog.12441 - Pubmed citation