title: Placental mesenchymal dysplasia presenting as a twin gestation with complete molar pregnancy.
abstract: BACKGROUND
  Placental mesenchymal dysplasia is a rare abnormality characterized by placentomegaly, grapelike cystic vesicles, and villous hyperplasia. The clinical and ultrasonographic presentation may mimic molar pregnancy, provoking incorrect diagnoses and unnecessary therapeutic interventions.
  
  
  METHODS
  A 36-year-old nulliparous woman presented for prenatal ultrasonography that indicated the presence of one gestational sac containing both fetus and cystic mass, concerning for partial molar pregnancy. Amniocentesis returned a 46,XX karyotype, suggesting a twin gestation with complete mole. The patient was monitored closely and, because of fetal growth restriction, was induced successfully at term and delivered a healthy newborn. Histopathologic findings of the placenta were consistent with placental mesenchymal dysplasia.
  
  
  CONCLUSIONS
  Although placental mesenchymal dysplasia is often confused with molar pregnancy, it is important to consider both in a differential to avoid inappropriate treatments.
authors.affiliation: From the Division of Maternal-Fetal Medicine, the Program in Women's Oncology, and the Department of Pathology, Women & Infants Hospital, Providence, Rhode Island; the Departments of Obstetrics-Gynecology and Medicine, The Warren Alpert Medical School of Brown University, Providence, Rhode Island; and Albany Medical College, Albany, New York.
authors.forename: Roman
authors.initials: R
authors.lastname: Starikov
authors.forename: Randi
authors.initials: R
authors.lastname: Goldman
authors.forename: Don S
authors.initials: DS
authors.lastname: Dizon
authors.forename: Stefan
authors.initials: S
authors.lastname: Kostadinov
authors.forename: Stephen
authors.initials: S
authors.lastname: Carr
mesh_terms: D000328:Adult; D000649:Amniocentesis; D036861:Delivery, Obstetric; D005260:Female; D058746:Gestational Sac / Q000098:blood supply / Q000000981:diagnostic imaging; D006801:Humans; D006828:Hydatidiform Mole / Q000098:blood supply / Q000175:diagnosis* / Q000000981:diagnostic imaging; D007231:Infant, Newborn; D008648:Mesoderm / Q000098:blood supply / Q000000981:diagnostic imaging; D010920:Placenta / Q000002:abnormalities* / Q000098:blood supply / Q000000981:diagnostic imaging; D010922:Placenta Diseases / Q000175:diagnosis* / Q000000981:diagnostic imaging; D011247:Pregnancy; D011256:Pregnancy Outcome; D014427:Twins; D016216:Ultrasonography, Prenatal