title: Amnion degeneration over fetal placental surface vessels possibly resulting from focal hypoxia: a case report.
abstract: The monoamnionic placenta of this twin gestation had focal amnion necrosis, but this was present only over the fetal surface vessels of one twin; this twin also developed cerebral atrophy. We hypothesize that this degeneration is due to a more severely reduced oxygen tension in its vessels. The placental amnion epithelium may undergo several degenerative processes, including amnion nodosum and changes due to meconium staining. Sonography had disclosed what appeared to be a dividing membrane, but this was not found at birth when monoamnionic twins with entangled cords presented. The amnion degeneration was present only over the large surface fetal vessels of the placenta of that twin who also developed central nervous system degeneration, and macrophage infiltration was confined to the same lesions. Focal hypoxia from entangling cords may have caused this defect.
authors.affiliation: Department of Pathology, University of California San Diego, School of Medicine, UCSD Medical Center 92103-8720, USA.
authors.forename: Yuichiro
authors.initials: Y
authors.lastname: Sato
authors.forename: Kurt
authors.initials: K
authors.lastname: Benirschke
mesh_terms: D000650:Amnion / Q000000981:diagnostic imaging / Q000473:pathology*; D004200:Diseases in Twins / Q000209:etiology*; D005260:Female; D005313:Fetal Death; D005315:Fetal Diseases / Q000000981:diagnostic imaging / Q000473:pathology*; D005311:Fetal Hypoxia / Q000503:physiopathology*; D006801:Humans; D009336:Necrosis / Q000000981:diagnostic imaging / Q000473:pathology; D010920:Placenta / Q000000981:diagnostic imaging / Q000473:pathology*; D011247:Pregnancy; D011272:Pregnancy, Multiple; D014057:Tomography, X-Ray Computed; D014430:Twins, Monozygotic; D016216:Ultrasonography, Prenatal; D014470:Umbilical Cord / Q000098:blood supply