[P-06] Excess subchorionic fibrinoid deposition as another variant of maternal floor infarct/massive perivillous fibrin deposit

Mana Taweevisit1,2

  1. Department of Pathology, Faculty of Medicine, Chulalongkorn University, Thailand
  2. King Chulalongkorn Memorial Hospital and Thai Red Cross Society, Thailand

 

Background: Maternal floor infarction (MFI) and massive perivillous fibrin deposition (MPFD) are placental disorders of unknown aetiology, associated with adverse obstetric outcome. Its morphology is characterised by marked increase in perivillous fibrinoid deposition in the intervillous space. The distribution of such fibrinoid deposition in MFI and MPFD often overlaps, suggesting both conditions represented the final common pathway for a number of different insults.

Case Presentation: We describe a 31-year-old mother diagnosed with immune thrombocytopenia who delivered a normal female neonate. She delivered at term, whose weight was appropriate for gestational age, with a placental weigh of < 10th percentile. Placenta examination showed MPFD with excessive subchorionic perivillous fibrinoid deposit, the morphology of which has never been reported. The chorionic plate of the placenta showed confluent firm, gray-white areas. These areas formed a thick rind over the chorionic plate measuring up to 4 mm, with vertical extension into the placental parenchyma in a serpiginous appearance. Such the gray-white lesion accounted for approximately 30% of the total placental volume with some areas of basal plate involvement. The histology revealed obliteration of the intervillous space by amorphous eosinophilic fibrinoid material corresponding to the gray-white areas observed grossly. The c4d immunohistochemistry was positive in most placental villi in a linear pattern along syncytiotrophoblastic layer.

Discussion and Conclusion: To our knowledge, the appearance of excessive subchorionic perivillous fibrinoid deposit has never been reported and it is considered to be another morphologic variation of MFI/MPFD. Immunologic reaction was presumably involved in pathogenesis.