Difference between revisions of "Placenta"

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(→‎Chorangioma: +link to image, ref)
(redo refs)
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==Normal==
==Normal==
Amnion - next to fetus, surrounds amniotic fluid, avascular.
Amnion - next to fetus, surrounds amniotic fluid, avascular.
*Characterized by a single layer of cells.<ref>Sternberg. Histo. for Pathol. 2nd Ed. P.974</ref>
*Characterized by a single layer of cells.<ref name=Ref_H4P2_974>{{Ref H4P2|974}}</ref>
**Cuboidal/squamoid shape.
**Cuboidal/squamoid shape.
**Eosinophilic cytoplasm.
**Eosinophilic cytoplasm.
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*Squamous metaplasia may be seen at cord insertion.
*Squamous metaplasia may be seen at cord insertion.
*Basement membrane.
*Basement membrane.
*'Compact layer'.<ref>H4P 2nd Ed., P.974.</ref>
*'Compact layer'.<ref name=Ref_H4P2_974>{{Ref H4P2|974}}</ref>
*'Fibroblastic layer'.<ref>H4P 2nd Ed., P.974.</ref>
*'Fibroblastic layer'.<ref name=Ref_H4P2_974>{{Ref H4P2|974}}</ref>


Chorion - surrounds amnion
Chorion - surrounds amnion
*Layers:<ref>H4P 2nd Ed., P.977.</ref>
*Layers:<ref name=Ref_H4P2_977>{{Ref H4P2|977}}</ref>
**'Reticular layer' - cellular (inner aspect).
**'Reticular layer' - cellular (inner aspect).
**'Pseudo-basemement membrane'.
**'Pseudo-basemement membrane'.
**'Outer trophoblastic layer'.
**'Outer trophoblastic layer'.
*Has blood vessels.
*Has blood vessels.
*Opposed to "trophoblastic X cells" on side opposite of amnion.<ref>H4P 2nd Ed., P.974.</ref>
*Opposed to "trophoblastic X cells" on side opposite of amnion.<ref name=Ref_H4P2_974>{{Ref H4P2|974}}</ref>
**Beneath of the "trophoblastic X cells" is ''decidua'' (mnemonic ''NEW'' = nucleus central, eosinophilic, well-defined cell border), which is maternal tissue.  
**Beneath of the "trophoblastic X cells" is ''decidua'' (mnemonic ''NEW'' = nucleus central, eosinophilic, well-defined cell border), which is maternal tissue.  


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===Placental membranes===
===Placental membranes===
Appearance:<ref>Lester 2nd Ed. P.461</ref>
Appearance:<ref name=Ref_Lester461>{{Ref Lester|461}}</ref>
*Normal - shiny.
*Normal - shiny.
*Choriomnionitis - opaque/dull.
*Choriomnionitis - opaque/dull.
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===Diamnionic-monochorionic (DiMo)===
===Diamnionic-monochorionic (DiMo)===
*No interposed chorion.<ref>Histo. for Pathol. 2nd Ed. P.979</ref>
*No interposed chorion.<ref name=Ref_H4P2_979>{{Ref H4P2|979}}</ref>
*Always monozygotic.
*Always monozygotic.
*Highest risk of TTTS (twin-to-twin transfusion syndrome).
*Highest risk of TTTS (twin-to-twin transfusion syndrome).
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# necrosis - in vessels or Wharton jelly.
# necrosis - in vessels or Wharton jelly.


Note: There is no such thing as ''chorionitis''.<ref>ALS Feb 2009</ref>
Note: There is no such thing as ''chorionitis''.<ref>ALS. February 2009.</ref>
===IHC===
===IHC===
Useful to differentiate hemosiderin-laden macrophages and meconium laden macrophages:
Useful to differentiate hemosiderin-laden macrophages and meconium laden macrophages:
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