Types

 placental macroscopic anomalies

• placental developmental variations
• placental developmental anomalies

 placental microscopic lesions

• trophoblastic lesions
  • trophoblastic hyeprplasia
  • syncitial knots
  • fibrin deposition
    • focal perivillous fibrin deposition
    • subchorionic fibrin deposition
    • massive perivillous fibrin deposition (MPFD)
    • villous fibrinoid necrosis

• trophoblastic basement membrane
  • trophoblastic basement membrane thickening
  • trophoblastic basement membrane mineralization

• villous stroma lesions
  • villous stromal fibrosis
  • Hofbauer cells hyperplasia

• anomalies of placental villous vessels
  • placental villous vessels obliteration
  • medial hypertrophy of placental villous vessels
  • intimal thickening of placental villous vessels
  • intimal fibrosis of placental villous vessels
  • hemorrhagic vasculosis
  • thrombosis of placental villous vessels
  • placental villous vasculitis

• placental inflammation
  • amnionitis
    • acute chorioamnionitis

• placental fibrosis
  • massive placental fibrosis

Localization