Pathology of placenta
Pathology of placenta
Updated: 04/16/2019
© Jun Wang, MD, PhD
Anatomy/histology
- Fetomaternal organ
- Three parts
Umbilical cord: 1 vein, 2 arteries, Wharton’s
jelly, NO inflammatory infiltrate
Fetal membrane: Amnion, chorion, decidua, NO
inflammatory infiltrate in amnion
Placental plate: Cotyledons, primary chorionic
villi (solid outgrowth of cytotrophoblast into the syncytiotrophoblast),
secondary chorionic villi (primary villi +loose connective tissue core),
tertiary chorionic villi (secondary chorionic villi + blood vessel)
Physiology
- Material and gas exchange between fetus and mother
- Cytotrophoblast replacing endothelial cells of uterine spiral artery to maintain sufficient blood flow to placenta
Hormone production
- Estrogen:
Converted from fetal androgen
Maintain endometrium during pregnancy
Suppress gonadotropin secretion
Stimulate mammary gland development
Inhibit prolactin secretion
Promote uterine sensitivity to oxytocin
- Progesterone
Maintains a non-contractile uterus
Fosters development of an endometrium
conducive to pregnancy
- Human chorionic gonadotropin (hCG)
Heterodimer of alpha and beta subunits
Synthesized primarily by the villous
syncytiotrophoblast
Detectable 7–10 days after implantation, the
basis for early pregnancy tests
Peak levels reached at 8-10 weeks
Maintains maternal corpus luteum
Elevation of beta-hCG only: trophoblast tumors,
or pregnancy
Elevation of alpha-hCG only: pituitary tumors
Hyperglycosylated hCG: invasive
cytotrophoblasts, pregnancy
- Placental alkaline phosphatase
Regulate primordial germ cells migration in
developing fetus
- Others: activin, inhibin, human chorionic thyrotropin, etc
Frequently discussed non
neoplastic conditions
- Hydatidiform mole
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