Placental mesenchymal dysplasia

Placental mesenchymal dysplasia (PMD) is a rare, benign condition that is characterised by enlargement of the placenta with multiple bunch 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 a F:M of ~3.5:1.

Clinical presentation is diverse and nonspecific

  • fetal anomalies (i.e. fetal liver cysts or vascular malformations)
  • fetal overgrowth with Beckwith-Wiedemann syndrome (BWS) features (placentomegaly, omphalocele, macroglossia and visceromegaly)
Ultrasound

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 becomes aneurysmal.

MRI

One study showed that MRI could help differentiate between complete hydatidiform mole with coexistent fetus (CHMTF) by demonstrating PMD within the placenta and CHMTF within an extra fetal sac 4.

The outcome of the fetus is variable ranging from a completely normal fetus to an increased risk of IUGR or fetal demise.  

It was first described in 1991 by Moscoso et al.

Possible differential considerations include

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Article Information

rID: 40033
System: Obstetrics
Section: Pathology
Tag: cases
Synonyms or Alternate Spellings:
  • Mesenchymal dysplasia of placenta
  • Placental mesenchymal dysplasia (PMD)

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Cases and Figures

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