Twin pregnancy with a chimeric androgenetic and biparental placenta in one twin displaying placental mesenchymal dysplasia phenotype

Prenat Diagn. 2005 Nov;25(11):1048-56. doi: 10.1002/pd.1255.


Objectives: The aim was to report an unusual trizygotic pregnancy that resulted in live-born twins. The placenta of one twin had placental mesenchymal dysplasia (PMD), which resulted from a chimeric fusion of an androgenetic zygote and a normal biparental zygote. The literature review was summarized.

Methods: The case was first detected by prenatal ultrasound, and was then followed by a histologic and detailed genetic investigation. The literature on PMD, complete hydatidiform moles (CHMs), and placental mosaicism and chimerism was also reviewed.

Results: One placenta of a twin pregnancy was noted to be diffusely cystic and enlarged. The macroscopic and microscopic findings were consistent with the diagnosis of PMD; however, genetic findings confirmed confined placental chimerism involving a normal biparental 46,XY male conceptus and an androgenetic 46,XX complete hydatidiform mole.

Conclusions: This case represents a rare placental abnormality, PMD, which may have a diverse etiology. Therefore, detailed histologic and genetic analysis were performed for an accurate diagnosis.

Publication types

  • Case Reports
  • Review

MeSH terms

  • Chimerism
  • Female
  • Hemangioma / pathology
  • Humans
  • Hydatidiform Mole / diagnosis*
  • Male
  • Mosaicism
  • Placenta / pathology*
  • Placenta Diseases / diagnosis*
  • Pregnancy
  • Pregnancy Complications
  • Pregnancy, Multiple
  • Twins, Dizygotic / genetics*