Chapter 18 - Placenta Flashcards
What is the growing fetus normally surrounded by?
Amnion, chorion, and placental villi.
Are the contents of villi maternal or fetal?
What perfuses the intervillus spaces?
Fetal.
Maternal blood delivered via the uterine spiral arteries.
Distinguish between the morphologies of immature and mature villi.
Immature villi are large, open and pale, with unipolar trophoblastic proliferation.
Mature villi are small, with syncytial knots and perivillous fibrin.
Distinguish between di-di, di-mo, and mo-mo twin placentas.
Di-di has two chorionic plates and two sets of membranes.
Di-mo has one chorionic plate but two membranes.
Mo-mo has both fetuses in the same amniotic space.
*difference is when the ovum splits in development*
Describe the normal morphology of the umbilical cord.
Two arteries and one vein in a background of Wharton’s jelly.
Distinguish between funisitis and umbilical phlebitis.
Umbilical phlebitis is neutrophil migration into the vein wall; it indicates early funisitis, a fetal inflammatory response.
*More severe funisitis involves the arteries, then the Wharton’s jelly.
What is the membrane roll evaluated for normally?
Subchorionitis thru chorioamnionitis (neutrophils in the decidual are OK), which is a maternal response
Meconium staining (gold meconiophages)
Decidual vasculopathy (fibrinoid necrosis)
Fetal vasculopathy
Subchorionic fibrin
Describe the most severe grades of funisitis and chorioamnionitis.
Funisitis: Umbilical perivasculitis, with neutrophils spreading out from the vessels.
Necrotizing chorioamnionitis: Sheets of neutrophils, thickened amnionic basement membrane, and necrotic amnion.
What is the significance of finding fibrinoid necrosis in a placenta?
Probably respresents decidual vasculopathy, a hallmark of pre-eclampsia.
Describe the morphology of a hydatidiform mole.
Large swollen villi with no internal fetal vessels, circumferential (IE nonpolar) trophoblast proliferation, and lack of fetal parts (complete).
Distinguish between the appearance of complete and partial moles.
Complete moles are uniform with hydropic villi and no fetus.
Partial moles will hace two distinct populations of villi (normal and edematous) and can have fetal parts.
What is the significance of a placenta appearing more mature than the gestational age?
Hypermaturity, which may represent ischemia.
What happens to perivillous fibrin with placental maturity?
It increases, especialy around the larger stem villi.
Describe the morphologic appearance and significance of villitis.
An increase in chronic inflammation within the villi; usually indicates CMV or syphilis but rarely with an identifiable organism.
Distinguish between the appearance of heavy perivillous fibrin deposition and infarct.
Infarcts should have no nuclear material; in fibrin deposition the villi should still show nuclear detail.
Normal placental membranes.
- Amnion
- Artifactual space
- Chorion
- Decidua
Left: Immature villi
Arrow: Double layer lining of cells
Arrowhead: Capillaries with nucleated RBCs
Right: Mature villi
Arrow: Syncytial knots
Left: Di-di twin placenta
A/B: Amnion
C: Double-layer of chorion
Right: Di-mo twin placenta
A: Amnion with no chorion between
Normal umbilical cord section
Funisitis
Arrowheads: Neutrophils
Chorioamnionitis
Arrow: Abscess
Arrowhead: Amnionitis
Oval: Decidual inflammation (unremarkable)
Meconiophages
Fibrinoid necrosis
Subchorionic fibrin deposition (Arrow)
Arrowhead: Normal amnion
Molar villi
Arrow: Dense trophoblastic proliferation
Arrowhead: Enlarged villi with central cavities
Left: Infarct, with loss of basophilia and residual apoptotic bodies
Right: Perivillous fibrin, with good nuclear detail
Normal trophoblastic invasion of spiral arteries
