Difference between revisions of "Placenta"

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Placenta (view source)

Revision as of 12:55, 27 September 2013

3,601 bytes removed ,  12:55, 27 September 2013
→‎Placental meconium: split-out
(→‎Chorangiosis: split-out)
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==Placental meconium==
==Placental meconium==
*[[AKA]] ''meconium staining''.
{{Main|Placental meconium}}
===General===
*Associated with fetal distress.
*Small amount - at term - is considered to be normal.
 
Other meconium-related pathology:
*[[Meconium peritonitis]].
*[[Meconium ileus]].
 
===Gross===
*Green/green discolourization.
 
===Microscopic===
Features:<ref>ALS. 6 Febraury 2009.</ref>
*Meconium histiocytes - '''key feature'''.
**Macrophages with brown fine granular pigment.
*Pseudostratified epithelium (amnion) - low power.
*Amnion - columnar morphology (normally cuboidal).
*"Drop-out" of individual amnion cells / loss of individual cells.
 
Time of meconium passage:<ref name=pmid2413412>{{cite journal |author=Miller PW, Coen RW, Benirschke K |title=Dating the time interval from meconium passage to birth |journal=Obstet Gynecol |volume=66 |issue=4 |pages=459–62 |year=1985 |month=October |pmid=2413412 |doi= |url=}}</ref>
*<1 h - no staining of membranes.
*1-3 h - amnion is stained.
*>3 h - chorion is stained.
 
DDx:
*Hemosiderin-laden macrophages.
**This is sorted-out with an iron stain -- see below.
 
Notes:
*The above time course is disputed - in vitro experiments suggest it is considerably longer.<ref name=pmid19031358>{{cite journal |author=Funai EF, Labowsky AT, Drewes CE, Kliman HJ |title=Timing of fetal meconium absorption by amnionic macrophages |journal=Am J Perinatol |volume=26 |issue=1 |pages=93–7 |year=2009 |month=January |pmid=19031358 |doi=10.1055/s-0028-1103028 |url=}}</ref>
 
====Images====
<gallery>
Image:Meconium-laden_macrophages_high_mag.jpg | Meconium-laden macrophages - high mag. (WC)
Image:Meconium-laden_macrophages_intermed_mag.jpg | Meconium-laden macrophages - intermed. mag. (WC)
</gallery>
===Special stains===
*Hemosiderin +ve in hemosiderin-laden macrophages.
*PAS +ve in meconium-laden macrophages.<ref name=pmid11268705>{{cite journal |author=Povýsil C, Bennett R, Povýsilová V |title=CD 68 positivity of the so-called meconium corpuscles in human foetal intestine |journal=Cesk Patol |volume=37 |issue=1 |pages=7–9 |year=2001 |month=January |pmid=11268705 |doi= |url=}}</ref>
 
Useful to differentiate hemosiderin-laden macrophages and meconium laden macrophages:
*Hemosiderin stain -- +ve for old blood.
**Prussian-blue stain = hemosiderin stain.<ref>{{cite journal |author=Sienko A, Altshuler G |title=Meconium-induced umbilical vascular necrosis in abortuses and fetuses: a histopathologic study for cytokines |journal=Obstet Gynecol |volume=94 |issue=3 |pages=415?0 |year=1999 |month=September |pmid=10472870 |doi= |url=}}</ref>
 
Notes:
*PAS-D -- +ve in meconium... though may rarely stain hemosiderin.
*Meconium contains bile.<ref>{{cite journal |author=Sienko A, Altshuler G |title=Meconium-induced umbilical vascular necrosis in abortuses and fetuses: a histopathologic study for cytokines |journal=Obstet Gynecol |volume=94 |issue=3 |pages=415?0 |year=1999 |month=September |pmid=10472870 |doi= |url=}}</ref>
 
===Sign out===
<pre>
PLACENTA, UMBILICAL CORD AND FETAL MEMBRANES, BIRTH:
- FETAL MEMBRANES WITH MECONIUM-LADEN MACROPHAGES, NEGATIVE FOR CHORIOAMNIONITIS.
- THREE VESSEL UMBILICAL CORD WITHIN NORMAL LIMITS.
- PLACENTAL DISC WITH THIRD TRIMESTER VILLI WITHIN NORMAL LIMITS.
</pre>
 
<pre>
COMMENT:
A PAS-D stain and Prussian blue stain were used to confirm the presence of meconium.
</pre>
 
====Not definite====
<pre>
PLACENTA, UMBILICAL CORD AND FETAL MEMBRANES, CESAERIAN SECTION:
- EARLY CHORIOAMNIONITIS.
- FETAL MEMBRANES WITH FOCAL AMNION CELL DROP-OUT AND RARE PIGMENTED
  CELLS SUGGESTIVE OF MECONIUM.
- THREE VESSEL UMBILICAL CORD WITHIN NORMAL LIMITS.
- PLACENTAL DISC WITH THIRD TRIMESTER VILLI.
</pre>


==Squamous metaplasia of the amnion==
==Squamous metaplasia of the amnion==
Michael
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