Placenta and major chromosomal abnormalities
Placentas in late abortions associated with chromosomal abnormalities
(trisomy 13, 18, 21 and monosomy X in particular) may show abnormal gross
or histologic features.
The placenta may be either large or small for gestational age.
Rarely cysts may be grossly recognizable.
- immature villi.
- dysmorphic features of chorionic villi include cystic villi, irregular
villous outline, trophoblastic inclusions, stromal karyomegaly, aberrant
capillary pattern, chorangiosis (hypercapillarization)
- Rare cases mimicking partial mole were described in association with
trisomy 13. A population of large hydropic poorly vascularized villi
is present. Trophoblastic hyperplasia is absent. The risk of persisting
trophoblastic disease is not increased.
These features are not neither specific or constant in
chromosomal abnormalities and cannot be used for diagnosis as
the only sign.
Placenta mimicking partial mole, huge hydropic villi, poor vascularization,
no trophoblastic hyperplasia, normal villi:
Placenta, trisomy 13, HE 20x (72806)
Placenta, trisomy 13, HE 40x (72807)
Placenta in trisomy 21, 40-week stillborn infant,
retardation of villous maturation, aberrant vasculary pattern, choriangiosis:
Dystrophic placenta, Down syndrome, HE 20x (72866)