Difference between revisions of "Placenta"

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The '''placenta''' feeds the developing baby, breathes for it and disposes of its waste.
[[Image:Human_placenta.jpg|thumb|right|A placenta (fetal aspect) with attached umbilical cord. (WC/Asturnut)]]
The '''placenta''' feeds the developing baby, breathes for it and disposes of its waste.  


=Clinical=
The organ is one that seems to be left behind; at least one review suggests it isn't done so well by general pathologists.<ref name=pmid12033960>{{Cite journal  | last1 = Sun | first1 = CC. | last2 = Revell | first2 = VO. | last3 = Belli | first3 = AJ. | last4 = Viscardi | first4 = RM. | title = Discrepancy in pathologic diagnosis of placental lesions. | journal = Arch Pathol Lab Med | volume = 126 | issue = 6 | pages = 706-9 | month = Jun | year = 2002 | doi = 10.1043/0003-9985(2002)1260706:DIPDOP2.0.CO;2 | PMID = 12033960 }}</ref>
 
''Placental pathology'' redirects to this article.
 
=Clinical=  
==Examination of the placenta==
==Examination of the placenta==
*Most placentas are ''not'' examined by a pathologist.
*Most placentas are ''not'' examined by a pathologist.


Indications for exam by a pathologist:
===Indications for exam by pathology===
Some indications for exam by a pathologist:
*Abnormalities in the:
*Abnormalities in the:
*#Fetus:
*#Fetus:
*#*Bad fetal outcome.
*#*Bad fetal outcome.
*#*Suspected or known congenital abnormalities ''or'' chromosomal abnormalities.
*#*Suspected or known congenital abnormalities ''or'' chromosomal abnormalities.
*#*[[IUGR]].
*#Mother:
*#Mother:
*#*Infection/suspected infection.
*#*Infection/suspected infection.
*#*Pre-term labour.
*#*Pre-term labour.
*#*Maternal disease (e.g. SLE, coagulopathy).
*#*Maternal disease (e.g. [[SLE]], coagulopathy).
*#*Complicated pregnancy (preclampsia, pregnancy induced hypertension, gestational diabetes).
*#*Complicated pregnancy (preclampsia, pregnancy induced hypertension, gestational diabetes).
*#Placenta:
*#Placenta:
*#*Unusual gross characteristics.
*#*Unusual gross characteristics.<ref name=pmid9518951>{{cite journal |author=Yetter JF |title=Examination of the placenta |journal=Am Fam Physician |volume=57 |issue=5 |pages=1045–54 |year=1998 |month=March |pmid=9518951 |doi= |url=}}</ref>
 
A more detailed list is given by Hargitai et al.<ref name=pmid15280396>{{cite journal |author=Hargitai B, Marton T, Cox PM |title=Best practice no 178. Examination of the human placenta |journal=J. Clin. Pathol. |volume=57 |issue=8 |pages=785–92 |year=2004 |month=August |pmid=15280396 |pmc=1770400 |doi=10.1136/jcp.2003.014217 |url=}}</ref> and Chang.<ref>URL: [http://smj.sma.org.sg/5012/5012ra1.pdf http://smj.sma.org.sg/5012/5012ra1.pdf]. Accessed on: 11 February 2011.</ref>
 
====Most common====
Most common reasons for submitting a placenta to pathology:<ref>Sherman C. 8 February 2011.</ref>
# Prematurity.
# PROM / possible [[chorioamnionitis]].
# Multiple gestation.


==Bleeding in late pregnancy==
==Bleeding in late pregnancy==
DDx of bleeding in late pregnancy:
DDx of bleeding in late pregnancy:
*Placental abruption (most common).
*[[Placental abruption]] (most common).
*Placenta previa.
*Placenta previa.
*Vasa previa (fetus losing blood).
*Vasa previa (fetus losing blood).


==Clinical screening tests==
==Clinical screening tests==
{{main|Pregnancy}}
*PAPP-A - low values seen in aneuploidy.<ref>URL: [http://www.ncbi.nlm.nih.gov/sites/entrez?Db=gene&Cmd=ShowDetailView&TermToSearch=5069 http://www.ncbi.nlm.nih.gov/sites/entrez?Db=gene&Cmd=ShowDetailView&TermToSearch=5069]. Accessed on: 7 July 2010.</ref>
*PAPP-A - low values seen in aneuploidy.<ref>URL: [http://www.ncbi.nlm.nih.gov/sites/entrez?Db=gene&Cmd=ShowDetailView&TermToSearch=5069 http://www.ncbi.nlm.nih.gov/sites/entrez?Db=gene&Cmd=ShowDetailView&TermToSearch=5069]. Accessed on: 7 July 2010.</ref>


{{main|Pregnancy}}
==Abbreviations==
*C/S = Caesarean section.
*LSCS = lower segment C-section.
*FTP = failure to progress.
*PROM = premature rupture of membranes.
*PPROM = preterm premature ruptures of membranes.
*IUGR = [[intrauterine growth restriction]].
*IOL = induction of labour.


=Normal histology=
=Normal histology=
==Amnion==
==Villi==
{{Main|Chorionic villi}}
This is dealt with in a separate article that also covers the types of trophoblast ([[cytotrophoblast]], [[syncytiotrophoblast]], intermediate trophoblast).
 
==Cord==
===Omphalomesenteric duct remnant===
*[[AKA]] vitelline duct.
*Benign embryologic remnant.
 
Features:
*Duct with benign looking cuboidal epithelium.
 
===Allantoic duct remnant===
*Benign embryologic remnant.
 
Features:
*Duct with benign looking flat epithelium.
 
===Vitelline artery remnant===
Features:
*Small artery in the cord.
 
==Membranes==
Fetus to mother:
*Amnion - thin layer: one cell layer, basement membrane, connective tissue.
*Cleft - artifactual - empty space.
*Chorion - vascular.
*Decidua (maternal tissue) - may contain obsolete chorionic villi; place to look for hypertensive changes.
 
===Amnion===
General:  
General:  
*Next to fetus, surrounds amniotic fluid, avascular.
*Next to fetus, surrounds amniotic fluid, avascular.
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*'Fibroblastic layer'.<ref name=Ref_H4P2_974>{{Ref H4P2|974}}</ref>
*'Fibroblastic layer'.<ref name=Ref_H4P2_974>{{Ref H4P2|974}}</ref>


==Chorion==
===Chorion===
General:
General:
*Surrounds amnion.
*Surrounds amnion.
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*Has blood vessels.
*Has blood vessels.
*Opposed to "trophoblastic X cells" on side opposite of amnion.<ref name=Ref_H4P2_974>{{Ref H4P2|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.
 
Note:
*Fibrin deposition may be found deep to the chorion - known as ''subchorionic fibrin deposition''.
**Gross: subchorionic, white/yellow, laminated, classically has a triangular-shape with the base of triangle parallel to fetal aspect of disc.
***Arises due to localized stasis of the inter-villous maternal blood.
**Focal small deposits are considered to be a normal finding - seen in ~15% of cases.<ref name=pmid21393870>{{Cite journal  | last1 = Narasimha | first1 = A. | last2 = Vasudeva | first2 = DS. | title = Spectrum of changes in placenta in toxemia of pregnancy. | journal = Indian J Pathol Microbiol | volume = 54 | issue = 1 | pages = 15-20 | month =  | year =  | doi = 10.4103/0377-4929.77317 | PMID = 21393870 |URL = http://www.ijpmonline.org/article.asp?issn=0377-4929;year=2011;volume=54;issue=1;spage=15;epage=20;aulast=Narasimha }}</ref><ref>URL: [http://zulekhahospitals.com/uploads/files/Sub-chorionic.pdf http://zulekhahospitals.com/uploads/files/Sub-chorionic.pdf]. Accessed on: 17 August 2012.</ref>
***The pathologic counterpart of this is ''[[perivillous fibrin deposition]]''.
 
Image:
*[http://www.ijpmonline.org/viewimage.asp?img=IndianJPatholMicrobiol_2011_54_1_15_77317_u5.jpg Subchorionic fibrin deposition (ijpmonline.org)].


==Common terms==
==Common terms==
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**Disc.  
**Disc.  
**Length of cord, diameter of cord.
**Length of cord, diameter of cord.
*Mass (weight) -- should be done 'trimmed' (cord cut-off, membrane cut-off).
**Accessory lobes - dimensions.
***Two lobes of equal size + cord arises in between = bilobate placenta.
*Mass (weight).
**Should be done 'trimmed' (cord cut-off, membrane cut-off).
**Should be done when placenta is "fresh", i.e. not fixed -- as mass tables are based on fresh state.
*Umbilical cord  
*Umbilical cord  
**Attachment.
**Attachment.
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***Membranous or velamentous (veil-like) insertion.  
***Membranous or velamentous (veil-like) insertion.  
****Vessels separate/branch prior to reaching placental disc.
****Vessels separate/branch prior to reaching placental disc.
***Furcate insertion - vessel run on fetal surface (more exposed to trauma).
***Furcate insertion - blood vessels separate before reaching placenta disc/not surrounded by Wharton's jelly - vessels more exposed to trauma (risk for vasa previa).
**Knots (false vs. true).
**Knots (false vs. true).
***False knots are nothing to worry about -- look like a knot but aren't really one.
***False knots are nothing to worry about -- look like a knot but aren't really one.
**Twisting/coiling.
**Twisting/coiling - 1-3 coils/10 cm is normal.
**Number of vessels.
**Number of vessels.
***Normal: 2 arteries, 1 vein.
***Normal: 2 arteries, 1 vein.
*Membranes - shiny, thin, translucent
*Membranes - shiny & translucent - normal (green, opaque/dull - chorioamnionitis).
**Attachment: marginal (normal), circummarginate (inside edge), circumvallated (folding on self).
**Attachment (insertion): marginal (normal), circummarginate (inside edge), [[circumvallate placenta|circumvallate]] (folding on self).
**Site of rupture - if obvious; low point of rupture suggests low-lying placenta.
*Placental disc.
*Placental disc.
**Fetal surface - normal is shinny (dull in chorioamnionitis).
**Fetal surface - normal is shinny.
**Maternal surface - are the cotyledons intact?
***Dull in chorioamnionitis.
**Maternal surface  
***Are the cotyledons intact?
***Adherent clot?
**Parenchyma - after sectioning:
***White vs. red nodules.
 
Notes:
*Parenchymal nodules - a brief DDx:
**White: [[placental infarct|infarct]] (chronic), thrombi, [[chorangioma]], [[perivillous fibrin deposition]].
**Red: infarct (acute), thrombi.


==Sections==
==Sections==
*Cord two sections.
#Cord two sections.
*Cord at insertion.
#Membranes (rolled), two rolls or more.<ref name=pmid19061291>{{cite journal |author=Winters R, Waters BL |title=What is adequate sampling of extraplacental membranes?: a randomized, prospective analysis |journal=Arch. Pathol. Lab. Med. |volume=132 |issue=12 |pages=1920–3 |year=2008 |month=December |pmid=19061291 |doi= |url=}}</ref>
*Membranes (rolled).
#Cord at insertion + disc.
*Placenta - full thickness (maternal and fetal surface).
#Placenta - full thickness (maternal and fetal surface).
#*Sections should not be taken at the margin of the disc.


==Placental membranes==
==Placental membranes==
Appearance:<ref name=Ref_Lester461>{{Ref Lester|461}}</ref>
Appearance:<ref name=Ref_Lester461>{{Ref Lester|461}}</ref>
*Normal - shiny.
*Normal - shiny.
*Choriomnionitis - opaque/dull.
*[[Chorioamnionitis]] - opaque/dull.
*Meconium - green.
*Meconium - green.
*Amnion nodosum - yellow patches.
*[[Amnion nodosum]] - yellow patches.
**Some describe 'em as white.<ref>CS. 7 February 2011.</ref>


==Placental mass==
==Placental mass==
It is considered routine to obtain a mass for the placenta.  This is usually done when the placenta is fresh and with the membranes and cord trimmed, as most tables of placental mass were created with these parameters. 
Placental mass by gestational age:<ref>AFIP Placental pathol. ISBN: 1-881041-89-1. P.312</ref>
Placental mass by gestational age:<ref>AFIP Placental pathol. ISBN: 1-881041-89-1. P.312</ref>
{| class="wikitable"
{| class="wikitable"
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===Linear regression - placental mass-gestational age===
===Linear regression - placental mass-gestational age===
Based on the table in the AFIP book<ref>AFIP Placental pathol. ISBN: 1-881041-89-1. P.312</ref> I generated the following regression lines:
Based on the table in the AFIP book<ref>AFIP Placental pathol. ISBN: 1-881041-89-1. P.312</ref> one can generate the following regression lines:
{| class="wikitable"
{| class="wikitable"
| ||'''50%''' ||'''10%''' ||'''90%'''
| ||'''50%''' ||'''10%''' ||'''90%'''
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*The change in mass/week is approximately linear and equal to 300 grams / 14 weeks ~ 20 grams/week.
*The change in mass/week is approximately linear and equal to 300 grams / 14 weeks ~ 20 grams/week.
*The spread in mass between 10% and 90%, crudely estimated, is 200 grams (for GA=26-40).
*The spread in mass between 10% and 90%, crudely estimated, is 200 grams (for GA=26-40).
Notes:
*Is it required?
**Sebire and Fox have advocated abandoning the practise of obtaining a placental mass, due to the large number of uncontrolled variables inherent in these measures.  Instead, they have advocated using mushy descriptors such as "small", "average" and "large", which require experience in examining the organ.<ref>{{cite book |author= Fox, Harold; Sebire, Neil J. |title=[http://www.amazon.com/Pathology-Placenta-Major-Problems/dp/1416025928/ref=sr_1_fkmr0_1?ie=UTF8&qid=1297259619&sr=1-1-fkmr0 Pathology of the Placenta (Major Problems in Pathology)]|publisher=Saunders |location= |year=2007 |pages= 559-561 |edition=3rd |isbn=978-1416025924 |oclc= |doi= |accessdate=}}</ref> 
***In the context of quality, a measure (even if somewhat flawed) is probably more reproducible and objective than arbitrary descriptors which require experience and a continuing case volume to calibrate.
===Placentomegaly===
*[[AKA]] ''large placenta''.
Associations:<ref>URL: [http://quizlet.com/5793113/ob-flash-cards/ http://quizlet.com/5793113/ob-flash-cards/]. Accessed on: 13 January 2012.</ref>
*Maternal [[diabetes]] - esp. poorly controlled.<ref name=pmid2771897>{{Cite journal  | last1 = Clarson | first1 = C. | last2 = Tevaarwerk | first2 = GJ. | last3 = Harding | first3 = PG. | last4 = Chance | first4 = GW. | last5 = Haust | first5 = MD. | title = Placental weight in diabetic pregnancies. | journal = Placenta | volume = 10 | issue = 3 | pages = 275-81 | month =  | year =  | doi =  | PMID = 2771897 }}</ref>
*Maternal [[anemia]]/low maternal iron stores.<ref>{{Cite journal  | last1 = Hindmarsh | first1 = PC. | last2 = Geary | first2 = MP. | last3 = Rodeck | first3 = CH. | last4 = Jackson | first4 = MR. | last5 = Kingdom | first5 = JC. | title = Effect of early maternal iron stores on placental weight and structure. | journal = Lancet | volume = 356 | issue = 9231 | pages = 719-23 | month = Aug | year = 2000 | doi =  | PMID = 11085691 }}</ref>
*Fetal malformations.
*Neoplasms of the placenta, e.g. [[chorangioma]].
*Twin-twin transfusion syndrome.
*Chronic intrauterine infections, e.g. [[syphilis]], [[toxoplasmosis]], [[cytomegalovirus]].
Lame causes of a heavy placenta:
*Dates wrong - error in determining the estimated date of confinement.
*Adherent blood clot.
Comment:
*Most of causes seem to have one thing in common:
**There is a decreased oxygen delivery to the fetus.
====Sign out====
<pre>
PLACENTA, UMBILICAL CORD AND FETAL MEMBRANES, CESAERIAN SECTION:
- LARGE PLACENTA (819 GRAMS -- TRIMMED, POST-FIXATION WEIGHT).
- FETAL MEMBRANES WITHIN NORMAL LIMITS.
- THREE VESSEL UMBILICAL CORD WITHIN NORMAL LIMITS.
- PLACENTAL DISC WITH THIRD TRIMESTER VILLI.
</pre>
===Placental growth restriction===
*[[AKA]] ''placenta small for gestational age''.
*''Small placenta'' redirects here.
Associations:
*Maternal vascular disease, e.g. [[hypertrophic decidual vasculopathy|hypertension]].
*Fetal malformations.
====Sign out====
<pre>
PLACENTA, UMBILICAL CORD AND FETAL MEMBRANES, BIRTH:
- PLACENTA SMALL FOR GESTATIONAL AGE (160 GRAMS -- TRIMMED, POST-FIXATION WEIGHT).
- THREE VESSEL UMBILICAL CORD WITHIN NORMAL LIMITS.
- FETAL MEMBRANES WITHIN NORMAL LIMITS.
- PLACENTAL DISC WITH THIRD TRIMESTER VILLI WITH:
-- OLD CENTRAL TRANSMURAL INFARCT (1.7 CM MAXIMAL DIMENSION).
COMMENT:
The 10th percentile placental mass (pre-fixation) for 34 weeks and 2 days is approximately 390 grams.
</pre>


=Overview of placental pathology=
=Overview of placental pathology=
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==Common entities/diagnoses==
==Common entities/diagnoses==
*Normal.
*Normal.
*Chorioamnionitis.
*[[Chorioamnionitis]].
*Placental abruption.
*[[Placental abruption]].
*Meconium.
*[[Meconium]].
*Hypertensive changes.
*Hypertensive changes.


=Sign-out=
=Sign out=
What should be commented on...
What should be commented on...


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***Fetal.
***Fetal.
*Membranes.
*Membranes.
**Membranitis?
**[[Membranitis]]?
**Chorioamnionitis?
**[[Chorioamnionitis]]?
*Cord:
*Cord:
**3 vessel?
**3 vessel?
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Mnemonic: ''chorio, cord, vessels, villi (maturity, infarction)''.
Mnemonic: ''chorio, cord, vessels, villi (maturity, infarction)''.
==Normal placenta==
<pre>
PLACENTA, UMBILICAL CORD AND FETAL MEMBRANES, BIRTH:
- THREE VESSEL UMBILICAL CORD WITHIN NORMAL LIMITS.
- FETAL MEMBRANES WITHIN NORMAL LIMITS.
- PLACENTAL DISC WITH THIRD TRIMESTER VILLI WITHIN NORMAL LIMITS.
</pre>
===C-section===
<pre>
PLACENTA, UMBILICAL CORD AND FETAL MEMBRANES, CAESAREAN SECTION:
- THREE VESSEL UMBILICAL CORD WITHIN NORMAL LIMITS.
- FETAL MEMBRANES WITHIN NORMAL LIMITS.
- PLACENTAL DISC WITH THIRD TRIMESTER VILLI WITHIN NORMAL LIMITS.
</pre>


=Cord pathology=
=Cord pathology=
*Two vessel cord.
*[[Two vessel cord]].
*Hypercoiling.
*Hypercoiling/Hypocoiling.
*Abnormal insertion.
*Abnormal insertion.
*Cord knots (true vs. false).
*[[Cord knot]]s (true vs. false).
*Strictures.
*Strictures.
*Hematoma.
*Hematoma.
*[[Hemangioma]].
*Benign cyst.


==Two vessel cord==
==Two vessel umbilical cord==
*[[AKA]] single umbilical artery.
*[[AKA]] ''two vessel cord''.
*Associated with congenital abnormalities, esp. cardiac - '''key point'''.<ref name=Ref_WMSP464>{{Ref WMSP|464}}</ref>
*[[AKA]] ''single umbilical artery''.
**Thought to be an acquired defect (as prevalence is lower in early in gestation).
{{Main|Two vessel umbilical cord}}
*May be seen in association of other cord abnormalities (e.g. marginal insertion, velamentous insertion).
 
Image:
*[http://www.glowm.com/resources/glowm/graphics/figures/v2/1070/05b.jpg SUA (glown.com)].<ref>URL: [http://www.glowm.com/?p=glowm.cml/section_view&articleid=151 http://www.glowm.com/?p=glowm.cml/section_view&articleid=151]. Accessed on: 8 January 2011.</ref>


==Insertion==
==Insertion==
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*Increased risk of vasa previa.<ref name=pmid20872421>{{cite journal |author=Hasegawa J, Farina A, Nakamura M, ''et al.'' |title=Analysis of the ultrasonographic findings predictive of vasa previa |journal=Prenat. Diagn. |volume=30 |issue=12-13 |pages=1121–5 |year=2010 |month=December |pmid=20872421 |doi=10.1002/pd.2618 |url=}}</ref>
*Increased risk of vasa previa.<ref name=pmid20872421>{{cite journal |author=Hasegawa J, Farina A, Nakamura M, ''et al.'' |title=Analysis of the ultrasonographic findings predictive of vasa previa |journal=Prenat. Diagn. |volume=30 |issue=12-13 |pages=1121–5 |year=2010 |month=December |pmid=20872421 |doi=10.1002/pd.2618 |url=}}</ref>


==Knots==
====Sign out====
<pre>
PLACENTA, UMBILICAL CORDS AND FETAL MEMBRANES, BIRTH:
- THREE VESSEL UMBILICAL CORD WITH A VELAMENTOUS INSERTION, OTHERWISE WITHIN NORMAL LIMITS.
- FETAL MEMBRANES WITHIN NORMAL LIMITS.
- PLACENTAL DISC WITH THIRD TRIMESTER VILLI WITHIN NORMAL LIMITS.
</pre>
 
==Umbilical knot==
*[[AKA]] ''umbilical cord knot''.
*[[AKA]] ''cord knot''.
*[[AKA]] ''true knot''.
===General===
===General===
*Prevalence ~1.25%.<ref name=pmid12012287>{{cite journal |author=Airas U, Heinonen S |title=Clinical significance of true umbilical knots: a population-based analysis |journal=Am J Perinatol |volume=19 |issue=3 |pages=127–32 |year=2002 |month=April |pmid=12012287 |doi=10.1055/s-2002-25311 |url=}}</ref><ref name=Ref_WMSP>{{Ref WMSP|464}}</ref>
*Prevalence ~1.25%.<ref name=pmid12012287>{{cite journal |author=Airas U, Heinonen S |title=Clinical significance of true umbilical knots: a population-based analysis |journal=Am J Perinatol |volume=19 |issue=3 |pages=127–32 |year=2002 |month=April |pmid=12012287 |doi=10.1055/s-2002-25311 |url=}}</ref><ref name=Ref_WMSP>{{Ref WMSP|464}}</ref>
*Increase risk of stillbirth; odds ratio 3.93.<ref name=pmid12012287/>
*Increase risk of [[stillbirth]]; odds ratio 3.93.<ref name=pmid12012287/>


===Gross===
===Gross===
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===Microscopic===
===Microscopic===
Features:
Features:
*+/-Thrombi.
*+/-[[thrombosis|Thrombi]].
**Fibrin deposition.
**Fibrin deposition.
*+/-Lines of Zahn.
*+/-Lines of Zahn.
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==Coiling==
==Coiling==
*Hypo- and hypercoiling are both considered problematic.<ref name=Ref_WMSP464>{{Ref WMSP|464}}</ref>
**Normal: 1-3 coils/10 cm.<ref>CS. 7 February 2011.</ref>
*Associated with cord stricture, which is usu. at the fetal end of the cord.<ref name=Ref_WMSP465>{{Ref WMSP|465}}</ref>
Notes:
*There is little uniformity in how coiling is assessed in the medical literature - though 10% and 90% are considered the cut-points for normal.<ref name=pmid21080869>{{cite journal |author=Khong TY |title=Evidence-based pathology: umbilical cord coiling |journal=Pathology |volume=42 |issue=7 |pages=618–22 |year=2010 |month=December |pmid=21080869 |doi=10.3109/00313025.2010.520309 |url=}}</ref>
*There is little uniformity in how coiling is assessed in the medical literature - though 10% and 90% are considered the cut-points for normal.<ref name=pmid21080869>{{cite journal |author=Khong TY |title=Evidence-based pathology: umbilical cord coiling |journal=Pathology |volume=42 |issue=7 |pages=618–22 |year=2010 |month=December |pmid=21080869 |doi=10.3109/00313025.2010.520309 |url=}}</ref>
**What are the 10% and 90% cut-points? They are not given in WMSP. UT access to a journal article<ref name=pmid16076615>PMID 16076615.</ref> that might have it is screwed-up.
**What are the 10% and 90% cut-points? They are not given in WMSP. UT access to a journal article<ref name=pmid16076615>PMID 16076615.</ref> that might have it is screwed-up.
*Hypo- and hypercoiling are both considered problematic.<ref name=Ref_WMSP464>{{Ref WMSP|464}}</ref>
*Associated with cord stricture, which is usu. at the fetal end of the cord.<ref name=Ref_WMSP465>{{Ref WMSP|465}}</ref>


==Cord hematoma==
==Cord hematoma==
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*Rare ~ 1/5500.
*Rare ~ 1/5500.
*Mortality ~50% is severe.
*Mortality ~50% is severe.
Image: [http://flylib.com/books/2/953/1/html/2/43%20-%20Placenta_files/DA10C43FF12.png Hematoma (flylib.com)].<ref>URL: [http://flylib.com/books/en/2.953.1.49/1/ http://flylib.com/books/en/2.953.1.49/1/]. Accessed on: 10 January 2011.</ref>


=Membranes=
=Membranes=
*Squamous metaplasia.
*Squamous metaplasia.
*Chorioamnionitis - see ''infection'' section.
*[[Chorioamnionitis]] - see ''infection'' section.


==Amnion nodosum==
==Amnion nodosum==
*[[AKA]] ''squamous metaplasia of amnion''.<ref>URL: [http://medical-dictionary.thefreedictionary.com/amnion+nodosum http://medical-dictionary.thefreedictionary.com/amnion+nodosum]. Accessed on: 18 November 2010.</ref>
{{Main|Amnion nodosum}}
 
==Placental meconium==
{{Main|Placental meconium}}
 
==Squamous metaplasia of the amnion==
===General===
===General===
*Associated with (long-standing) oligohydramnios.<ref>URL: [http://library.med.utah.edu/WebPath/PLACHTML/PLAC042.html http://library.med.utah.edu/WebPath/PLACHTML/PLAC042.html]. Accessed on: 12 January 2011.</ref>
*Benign common finding thought to be of no clinical significance.<ref name=Ref_WMSP463>{{Ref WMSP|463}}</ref>
**One case report suggesting an association with [[chorioamnionitis]].<ref>{{Cite journal  | last1 = Chew | first1 = RH. | last2 = Silberberg | first2 = BK. | title = Possible association of acute inflammatory exudate in chorioamnionitis and amniotic squamous metaplasia. | journal = Am J Clin Pathol | volume = 93 | issue = 4 | pages = 582-5 | month = Apr | year = 1990 | doi =  | PMID = 2321592 }}</ref>
*Needs to be separated from amnion nodosum - '''important'''.<ref>CS. 7 February 2011.</ref>


===Gross===
===Gross===
*Yellow patch or yellow nodules.
Features:<ref name=pmid18081444>{{Cite journal  | last1 = Adeniran | first1 = AJ. | last2 = Stanek | first2 = J. | title = Amnion nodosum revisited: clinicopathologic and placental correlations. | journal = Arch Pathol Lab Med | volume = 131 | issue = 12 | pages = 1829-33 | month = Dec | year = 2007 | doi = 10.1043/1543-2165(2007)131[1829:ANRCAP]2.0.CO;2 | PMID = 18081444 }}</ref>
*White (or yellow) plaques - irregular outline.
 
DDx:
*[[Amnion nodosum]] - small (~1-5 mm), round, classically yellow.


Image: [http://www.webpathology.com/image.asp?n=2&Case=659 Amnion nodosum (webpathology.com)].
Images:
*[http://www.archivesofpathology.org/action/showFullPopup?id=i1543-2165-131-12-1829-f01&doi=10.1043%2F1543-2165%282007%29131%5B1829%3AANRCAP%5D2.0.CO%3B2 Amnion nodosum & squamous metaplasia of the amnion (archivesofpathology.org)].<ref name=pmid18081444/>
<!-- annoying use of '[' and ']' - had to go find escape characters here: http://www.w3schools.com/tags/ref_urlencode.asp -->


===Microscopic===
===Microscopic===
Features:
Features:<ref name=pmid18081444/>
*Simple epithelium of amnion replaced by (non-keratinizing) stratified squamous epithelium.
*Dense, paucicellular (pink) compact keratin - '''key feature'''.


Image: [http://www.webpathology.com/image.asp?case=659&n=3 Amnion nodosum (webpathology.com)].
Image:
*[http://flylib.com/books/2/953/1/html/2/43%20-%20Placenta_files/DA10C43FF29.png Squmous metaplasia of the amnion (flylib.com)].<ref>URL: [http://flylib.com/books/en/2.953.1.49/1/ http://flylib.com/books/en/2.953.1.49/1/]. Accessed on: 10 January 2011.</ref>


==Passage of meconium==
==Circumvallate placenta==
*[[AKA]] ''circumvallate insertion of the membranes''.
===General===
===General===
*Associated with fetal distress.
*May be associated with [[placental abruption]].<ref name=pmid18226129>{{Cite journal  | last1 = Suzuki | first1 = S. | title = Clinical significance of pregnancies with circumvallate placenta. | journal = J Obstet Gynaecol Res | volume = 34 | issue = 1 | pages = 51-4 | month = Feb | year = 2008 | doi = 10.1111/j.1447-0756.2007.00682.x | PMID = 18226129 }}</ref>
 
Note:
*Membranes usually attach to the edge of the placenta.


===Gross===
===Gross===
*Green/green discolourization.
*Fetal membranes attach to the fetal surface of the placenta away from the margin of the placental disc.  
 
===Microscopy===
Features:<ref>ALS. 6 Feb 2009.</ref>
*Macrophages with brown fine granular pigment.
*Columnar morphology (normally cuboidal).
*"Drop-out" of individual cell -- the loss of individual cells.


Level of staining and time:<ref>3 Apr 2009.</ref>
Classification:
*<1 h - no staining of membranes.
*Partial - not circumferential.
*1-3 h - amnion is stained.
*Complete.
*>3 h - chorion is stained.


DDx:
DDx:
*Hemosiderin-laden macrophages.
*[[Circummarginate placenta]].


Images:
Images:
*[http://commons.wikimedia.org/wiki/File:Meconium-laden_macrophages_high_mag.jpg Meconium-laden macrophages - high mag. (WC)].
*[http://library.med.utah.edu/nmw/mod2/Tutorial2/pics/circumvallate.jpg Circumvallate placenta - partial and complete (utah.edu)].
*[http://commons.wikimedia.org/wiki/File:Meconium-laden_macrophages_intermed_mag.jpg Meconium-laden macrophages - intermed. mag. (WC)].
*[http://library.med.utah.edu/WebPath/jpeg2/PLAC027.jpg Circumvallate placenta (utah.edu)].
 
===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>
*PAS-D -- +ve in chorioamnionitis???
 
Note:
*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>
 
==Squamous metaplasia==
*Benign common finding - no clinical significance.<ref name=Ref_WMSP463>{{Ref WMSP|463}}</ref>
 
Image:
*[http://flylib.com/books/2/953/1/html/2/43%20-%20Placenta_files/DA10C43FF29.png Squmous metaplasia of the amnion (flylib.com)].<ref>URL: [http://flylib.com/books/en/2.953.1.49/1/ http://flylib.com/books/en/2.953.1.49/1/]. Accessed on: 10 January 2011.</ref>


=Twin placentas=
=Twin placentas=
These are often submitted... even if they are normal.
{{Main|Twin placentas}}
These are often submitted... even if they are normal.  In these specimens, usually, the chorion is the key.


==General==
It covers:
No membrane between fetuses.
*Monozygotic vs. dizygotic twins.
*Split at approx. 7th day.
*Twin-to-twin transfusion syndrome.


===Diamnionic-monochorionic (DiMo)===
=Placental disc=
*No interposed chorion.<ref name=Ref_H4P2_979>{{Ref H4P2|979}}</ref>
==Villous edema==
*Always monozygotic.
===General===
*Highest risk of TTTS (twin-to-twin transfusion syndrome).
*Non-specific finding.
*Reported in associated with congenital adrenal hyperplasia for the stem villi.<ref name=pmid11045335>{{Cite journal  | last1 = Furuhashi | first1 = M. | last2 = Oda | first2 = H. | last3 = Nakashima | first3 = T. | title = Hydrops of placental stem villi complicated with fetal congenital adrenal hyperplasia. | journal = Arch Gynecol Obstet | volume = 264 | issue = 2 | pages = 101-4 | month = Sep | year = 2000 | doi =  | PMID = 11045335 }}</ref>


===Diamnionic-dichorionic (DiDi)===
===Microscopic===
*Most dizygotic (70%), may be monozygotic (30%).
Features:
*If monozygotic -- split before 3 days.
*"Swiss chesse-like" appearance / bubbly appearance.
*Usually patchy and focal.


==Twin-to-twin transfusion syndrome==
Note:
===General===
*Cistern formation is reported in the stem villi in association with congenital adrenal hyperplasia.<ref name=pmid11045335/>
*Abbreviated as TTTS.


Definition:
DDx:  
*Monozygotic twins that share a placental disc, have vessels which cross-over between the twins that lead to a blood imbalance between the two twins.
*[[Chorioamnionitis]].
**Only seen in monozygotic twins.
*Fetal edema.
**Vascular connection may be vein-to-vein, artery-to-vein, artery-to-artery (uncommon).<ref name=Ref_WMSP469>{{Ref WMSP|469}}</ref>
*Idiopathic (no cause apparent).
*[[Placental villous immaturity]].


Prevalence:
Image:
*Seen in ~15% of monozygotic twins.<ref name=Ref_WMSP469>{{Ref WMSP|469}}</ref>
*[http://www.med.yale.edu/obgyn/kliman/placenta/articles/EOR_Placenta/Image19.gif villous edema (yale.edu)].<ref>URL: [http://www.med.yale.edu/obgyn/kliman/placenta/articles/EOR_Placenta/Trophtoplacenta.html http://www.med.yale.edu/obgyn/kliman/placenta/articles/EOR_Placenta/Trophtoplacenta.html]. Accessed on: 28 May 2011.</ref>
 
Clinical:
*Donor:
**Twin: hypovolemic, oliguric, oligohydramnic, +/- anemia, +/-hypoglycemia, +/- small pale organs.
**Placental disc: large, pale.
*Recipient:
**Twin: hypervolemia, polyuria, polyhydramnios, +/- hydrops fetalis, +/- CHF, hemolytic janundice, +/- large congested organs.
**Placental disc: small, firm, congested.


===Gross===
==Placental villous immaturity==
*Large vessels that connect the two umbilical cords.
{{Main|Placental villous immaturity}}


===Microscopic===
==Villous hypoplasia==
Features:<ref name=Ref_WMSP469-70>{{Ref WMSP|469-70}}</ref>
*[[AKA]] ''terminal villus deficiency''.<ref name=Ref_Placenta346>{{Ref Placenta|346}}</ref>
*Artery-to-vein anatomosis - where artery and vein are associated with different umbilical cords.
{{Main|Villous hypoplasia}}
*Donor twin side of placenta:
**Edematous villi.
**Increased nucleated RBCs.
*Recipient twin side of placenta:
**Congested.


=Diseases of the placental attachment=
=Diseases of the placental attachment=
==Placenta acreta/percreta/increta==
==Placenta creta==
Placenta attaches to the uterus deeper than it should.
Includes ''placenta accreta'', ''placenta increta'', and ''placenta percreta''.
{{Main|Placenta creta}}


==Placental abruption==
==Placental abruption==
===General===
{{Main|Placental abruption}}
Classic clinical manifestations:<ref name=pmid16752262>{{cite journal |author=Tikkanen M, Nuutila M, Hiilesmaa V, Paavonen J, Ylikorkala O |title=Clinical presentation and risk factors of placental abruption |journal=Acta Obstet Gynecol Scand |volume=85 |issue=6 |pages=700–5 |year=2006 |pmid=16752262 |doi=10.1080/00016340500449915 |url=}}</ref>
*Vaginal bleeding (~70%).
*Abdominal pain (~50%).
*Fetal heart rate abnormalities (~70%).


===Pathologic findings===
=Inflammatory pathologies=
Features:
===Overview of infections===  
*Gross pathology: depression on maternal side, large blood clot.
General:<ref name=Ref_PBoD1106>{{Ref PBoD|1106}}</ref>
**Central haemorrhage is the most worrisome.
 
Note:
*There are '''no''' good microscopic findings for placental abruption.
 
=Infection=
==General<ref name=Ref_PBoD1106>{{Ref PBoD|1106}}</ref>==
*Infection usually ascending, i.e. from vagina up through cervix.
*Infection usually ascending, i.e. from vagina up through cervix.
**Assoc. with intercourse.
**Associated with intercourse.
*Hematogenous rare - manifest as villitis.
*Hematogenous rare - manifest as villitis.
**Think ''[[TORCH infections]]'' (toxoplasmosis, others ([[syphilis]], TB, listeriosis), rubella, cytomegalovirus, herpes simplex virus).
**Think ''[[TORCH infections]]'' ([[toxoplasmosis]], others ([[syphilis]], [[TB]], listeriosis), rubella, [[cytomegalovirus]], [[herpes simplex virus]]).
*Funisitis usually follows chorioamnionitis.
*Funisitis usually follows chorioamnionitis.
**Inflammatory cells in umbilical cord are fetal (trivia).
**Inflammatory cells in umbilical cord are fetal (trivia).


===Types (by site)<ref name=Ref_PBoD1106>{{Ref PBoD|1106}}</ref>===
====Types====
By site:<ref name=Ref_PBoD1106>{{Ref PBoD|1106}}</ref>
*Fetal membranes: chorioamnionitis, membranitis.<ref name=Ref_Sternberg4_2311>{{Ref Sternberg4|2311}}</ref>
*Fetal membranes: chorioamnionitis, membranitis.<ref name=Ref_Sternberg4_2311>{{Ref Sternberg4|2311}}</ref>
*Umbilical cord: funisitis.
*Umbilical cord: funisitis.
*Placenta: placentitis, villitis.
*Placenta: placentitis, villitis.


==Grading infection (chorioamnionitis, membranitis, funisitis)==
==Membranitis==
Membranitis:<ref name=Ref_Sternberg4_2311>{{Ref Sternberg4|2311}}</ref>
:''Chorionitis'' redirects here.
===General===
*Early [[chorioamnionitis]].<ref>{{Cite journal  | last1 = Vedovato | first1 = S. | last2 = Zanardo | first2 = V. | title = [Chorioamnionitis and inflammatory disease in the premature newborn infant]. | journal = Minerva Pediatr | volume = 62 | issue = 3 Suppl 1 | pages = 155-6 | month = Jun | year = 2010 | doi =  | PMID = 21090086 }}</ref>
*Controversial.{{fact}}
 
===Microscopic===
Features:
*[[PMN]]s in the decidua.
*+/-PMNs in subamniotic tissue.
*+/-Necrosis in decidua or chorion/subamniotic tissue.
 
Note:
*Plasma cells in the decidua = [[chronic deciduitis]].
 
DDx:
*[[Chorioamnionitis]].
 
====Grading membranitis====
''Sternberg'':<ref name=Ref_Sternberg4_2311>{{Ref Sternberg4|2311}}</ref>
# PMNs - decidua only.
# PMNs - decidua only.
# PMNs - in subamniotic tissue.
# PMNs - in subamniotic tissue.
# 1 or 2 + necrosis in decidua or chorion/subamniotic tissue.
# 1 or 2 + [[necrosis]] in decidua or chorion/subamniotic tissue.


Chorioamnionitis:<ref name=Ref_Sternberg4_2311>{{Ref Sternberg4|2311}}</ref>
===Sign out===
# placental chorionic plate only.
<pre>
# 1 + subamniotic tissue.
PLACENTA, UMBILICAL CORD AND FETAL MEMBRANES, CESAERIAN SECTION:
# 1 or 2 + necrosis or abscess.
- FETAL MEMBRANES WITH CHORIONITIS.
- THREE VESSEL UMBILICAL CORD WITH VASCULITIS.
- PLACENTAL DISC WITH THIRD TRIMESTER VILLI.
</pre>


Sternberg separates ''vasculitis'' and ''funisitis'' without really explaining the terms<ref name=Ref_Sternberg4_2311>{{Ref Sternberg4|2311}}</ref> -- I presume:
====Waffle====
''vasculitis'' = inflammation of vessels in the umbilical cord.
<pre>
''funisitis'' = inflammation of the cord (vessels and Wharton jelly).
PLACENTA, UMBILICAL CORD AND FETAL MEMBRANES, BIRTH:
- FETAL MEMBRANES WITH MECONIUM-LADEN MACROPHAGES AND ABUNDANT DECIDUAL NEUTROPHILS
  SUSPICIOUS FOR EARLY CHORIONITIS.
- PLACENTAL DISC WITH THIRD TRIMESTER VILLI.
- THREE VESSEL UMBILICAL CORD WITHIN NORMAL LIMITS.
</pre>


Umbilical cord vasculitis:<ref name=Ref_Sternberg4_2311>{{Ref Sternberg4|2311}}</ref>
==Chorioamnionitis==
* +0.5 for each vessel.
{{Main|Chorioamnionitis}}
* +0.5 for each vessel with severe involvement.


Umbilical funisitis:<ref name=Ref_Sternberg4_2311>{{Ref Sternberg4|2311}}</ref>
==Umbilical cord vasculitis==
# focal inflammation.
{{Main|Umbilical cord vasculitis}}
# diffuse inflammation.
# necrosis - in vessels or Wharton jelly.


Note: There is no such thing as ''chorionitis''.<ref>ALS. February 2009.</ref>
==Funisitis==
{{Main|Funisitis}}
*Inflammation of Wharton's jelly - the connective tissue of the umbilical cord.
 
==Acute villitis==
{{main|Acute villitis}}


==Villitis of unknown etiology==
==Villitis of unknown etiology==
*Abbreviated ''VUE''.
{{Main|Villitis of unknown etiology}}
 
==Chronic intervillitis==
*[[AKA]] ''chronic intervillositis''.<ref name=pmid8215826>{{Cite journal  | last1 = Jacques | first1 = SM. | last2 = Qureshi | first2 = F. | title = Chronic intervillositis of the placenta. | journal = Arch Pathol Lab Med | volume = 117 | issue = 10 | pages = 1032-5 | month = Oct | year = 1993 | doi =  | PMID = 8215826 }}</ref>
 
===General===
===General===
Features:<ref name=pmid17889674>{{cite journal |author=Redline RW |title=Villitis of unknown etiology: noninfectious chronic villitis in the placenta |journal=Hum. Pathol. |volume=38 |issue=10 |pages=1439–46 |year=2007 |month=October |pmid=17889674 |doi=10.1016/j.humpath.2007.05.025 |url=}}</ref>
*Rare.
*Usu. term placenta.
*Massive chronic intervillitis - associated [[IUGR]], spontaneous abortion, perinatal fetal death.<ref name=pmid17088773>{{Cite journal | last1 = Rota | first1 = C. | last2 = Carles | first2 = D. | last3 = Schaeffer | first3 = V. | last4 = Guyon | first4 = F. | last5 = Saura | first5 = R. | last6 = Horovitz | first6 = J. | title = [Perinatal prognosis of pregnancies complicated by placental chronic intervillitis]. | journal = J Gynecol Obstet Biol Reprod (Paris) | volume = 35 | issue = 7 | pages = 711-9 | month = Nov | year = 2006 | doi = | PMID = 17088773 }}</ref>
*Prevalence: 5% to 15% of all placentas.
*Recurs.
*Associated with:
**Intrauterine growth restriction.
**Recurrent reproductive loss.
 
===Microscopic===
===Microscopic===
Features:<ref name=pmid17889674/>
Features:<ref name=pmid8215826/><ref name=pmid17088773/>
*Maternal T-lymphocytes (mostly CD8-positive) in villous stroma.  
*Intervillous inflammatory cells:
*+/-Intervillositis (lymphocytes between villi).
**Lymphocytes.
**Histiocytes.
*Fibrinoid deposition.


Images:
====Images====
*[http://jcp.bmj.com/content/61/12/1254/F6.large.jpg VUE (bmj.com)].<ref>URL: [http://jcp.bmj.com/content/61/12/1254.abstract http://jcp.bmj.com/content/61/12/1254.abstract]. Accessed on: 11 January 2011.</ref>
<gallery>
*[http://farm4.static.flickr.com/3501/3954021698_84a3542b43.jpg VUE (flickr.com)].<ref>URL: [http://www.flickr.com/photos/jian-hua_qiao_md/3954021698/ http://www.flickr.com/photos/jian-hua_qiao_md/3954021698/]. Accessed on: 11 January 2011.</ref> **CHECK**
Image:Intervillitis_-_intermed_mag.jpg | Intervillitis - intermed. mag. (WC)
Image:Intervillitis_-_very_high_mag.jpg | Intervillitis - very high mag. (WC)
</gallery>
==Chronic deciduitis==
*[[AKA]] plasma cell deciduitis.
{{Main|Chronic deciduitis}}


=Infarction=
=Placental infarction=
==True infarcts==
==True infarcts==
{{Main|Placental infarct}}
==Perivillous fibrin deposition==
*Abbreviation ''PFD''.
===General===
===General===
*Associated with retroplacental hematoma.
*Thought to be an immunologic problem - resulting in platelet activation and fibrin deposition.<ref name=pmid12066949>{{Cite journal  | last1 = Sebire | first1 = NJ. | last2 = Backos | first2 = M. | last3 = Goldin | first3 = RD. | last4 = Regan | first4 = L. | title = Placental massive perivillous fibrin deposition associated with antiphospholipid antibody syndrome. | journal = BJOG | volume = 109 | issue = 5 | pages = 570-3 | month = May | year = 2002 | doi =  | PMID = 12066949 }}</ref>
*May be associated with [[diabetes mellitus]].<ref name=Ref_Placenta327>{{Ref Placenta|327}}</ref>


===Gross===
===Gross===
Features:<ref name=Ref_WMSP465>{{Ref WMSP|465}}</ref>
*Pale (white).
*Early - red.
*Firm.
*Late - white/grey.
*White fibrous sepatae.
 
Images:
*[http://pathweb.uchc.edu/eatlas/gyn/681b.htm Placental infarcts (pathweb.uchc.edu)].
*[http://library.med.utah.edu/WebPath/PLACHTML/PLAC044.html Placental infarcts (med.utah.edu)].


===Microscopic===
===Microscopic===
Features:
Features:
#Necrosis of villi; hyaline material (acellular eosinophilic material) replaces the stroma of the villi.
*Acellular eosinophilic material around formed villi.
#Loss of intervillous space.<ref name=Ref_WMSP465>{{Ref WMSP|465}}</ref>
*Obliteration of intervillous space.
#*Villi appear to be crowded.<ref>{{Ref PBoD|1109}}</ref>
**Intervillous distance increased vis-a-vis normal - '''key feature'''.
#**Normal spacing is ~1x smallest villus or larger.
#Prominent syncytial knots.
#Thickened trophoblastic basement membrance (below [[cytotrophoblast]]s).
#+/-Changes seen in decidual vasculopathy:
#*Acute atherosis (vaguely like [[atherosclerosis]]).
#**Fibrioid necrosis.
#**Vessel wall lipid deposition.


Images:
Notes:
*[http://pathweb.uchc.edu/eatlas/gyn/1203b.htm Recent infarct (pathweb.uchc.edu)].
*Nuclei of villi are usually preserved.
*[http://path.upmc.edu/cases/case75/images/micro1.jpg Placental infarct (umpmc.edu)].<ref>URL: [http://path.upmc.edu/cases/case75/micro.html http://path.upmc.edu/cases/case75/micro.html]. Accessed on: 6 January 2011.</ref>
*Villi may have secondary infarction, i.e. there may be [[Basics#Nuclear destruction words|nuclear destruction]] (karyolysis, karyorrhexis, pyknosis).
*[http://www.mda-sy.com/pathology/PLACHTML/PLAC024.HTM Placental infarct - necrotic villi (mda-sy.com)].


===Significant infarcts===
DDx:
*> 3cm --or-- central location --or-- in 1st or 2nd trimester.
*[[Placental infarction]] - loss of nuclei in the villi (below the edge of the lesion).
**Small foci are accepted in term placentae - typically at periphery.
*[[Massive perivillous fibrin deposition]] (maternal floor infarct).


==Perivillous fibrin deposition==
Images:
*Massive perivillous fibrin deposition is assoc. with anti-phospholipid antibody (APLA) syndrome.<ref name=pmid12066949>{{cite journal |author=Sebire NJ, Backos M, Goldin RD, Regan L |title=Placental massive perivillous fibrin deposition associated with antiphospholipid antibody syndrome |journal=BJOG |volume=109 |issue=5 |pages=570–3 |year=2002 |month=May |pmid=12066949 |doi= |url=http://www3.interscience.wiley.com/resolve/openurl?genre=article&sid=nlm:pubmed&issn=1470-0328&date=2002&volume=109&issue=5&spage=570}}</ref>
*[http://path.upmc.edu/cases/case75.html APLA syndrome (upmc.edu)].
**APLA is assoc. with recurrent miscarriage - can be treated with heparin + ASA.<ref name=pmid12066949/>
*Thought to be an immunologic problem - resulting in platelet activation and fibrin deposition.<ref name=pmid12066949/>


===Gross===
===Sign out===
*Pale (white).
====Thrombi====
*Firm.
<pre>
*White fibrous sepatae.
PLACENTA, UMBILICAL CORD AND FETAL MEMBRANES, BIRTH:
- THREE VESSEL UMBILICAL CORD WITHIN NORMAL LIMITS.
- FETAL MEMBRANES WITHIN NORMAL LIMITS.
- PLACENTAL DISC WITH THIRD TRIMESTER VILLI AND THREE LARGE INTERVILLOUS
THROMBI (BLOCKS A7-A9).
</pre>


===Microscopy===
==Maternal floor infarction==
*Acellular eosinophilic material around formed villi.
*Abbreviated ''MFI''.
**Obliteration of intervillous space.
*Formally ''placental maternal floor infarction''.
*[[AKA]] ''massive perivillous fibrin deposition''.<ref name=Ref_Placenta367>{{Ref Placenta|367}}</ref>
{{Main|Maternal floor infarction}}


=Fetal disease=
=Fetal disease=
==Fetal thrombotic vasculopathy==
==Fetal thrombotic vasculopathy==
===General===
*Abbreviated ''FTV''.
*May cause IUGR.
*A large number of terms are used for this including:<ref name=pmid19237859>{{Cite journal | last1 = Marchetti | first1 = D. | last2 = Belviso | first2 = M. | last3 = Fulcheri | first3 = E. | title = A case of stillbirth: the importance of placental investigation in medico-legal practice. | journal = Am J Forensic Med Pathol | volume = 30 | issue = 1 | pages = 64-8 | month = Mar | year = 2009 | doi = 10.1097/PAF.0b013e318187387e | PMID = 19237859 }}</ref>  
*Associated with cerebral palsy and common in perinatal deaths.<ref name=pmid10414494>{{cite journal |author=Kraus FT, Acheen VI |title=Fetal thrombotic vasculopathy in the placenta: cerebral thrombi and infarcts, coagulopathies, and cerebral palsy |journal=Hum. Pathol. |volume=30 |issue=7 |pages=759–69 |year=1999 |month=July |pmid=10414494 |doi= |url=}}</ref>
**''Fibrinous vasculosis''.
 
**''Fibromuscular sclerosis''.
===Microscopic===
**''Fetal artery stem thrombosis''.
Features:
*The multitude of terms reflects the confusion about this finding and that it has numerous etiologies.<ref name=pmid19237859/>
*Thrombus in the fetal vasculature +/- recanalization.  
{{Main|Fetal thrombotic vasculopathy}}
**Eosinophilic (light pink on H&E), moderately granular intravascular material (fibrin) with layering.
 
Images:
*[http://jcp.bmj.com/content/61/12/1254/F8.large.jpg FTV (bmj.com)].<ref>URL: [http://jcp.bmj.com/content/61/12/1254.abstract http://jcp.bmj.com/content/61/12/1254.abstract]. Accessed on: 12 January 2011.</ref>
*[http://gut.bmj.com/content/41/3/354/F3.large.jpg Thrombus - rat (bmj.com)].<ref>URL: [http://gut.bmj.com/content/41/3/354.full http://gut.bmj.com/content/41/3/354.full]. Accessed on: 12 January 2011.</ref>


==Hemorrhagic endovasculitis==
==Hemorrhagic endovasculitis==
Line 538: Line 699:
=Maternal disease=
=Maternal disease=
==Hypertensive changes==
==Hypertensive changes==
Features:<ref name=pmid6754249>{{cite journal |author=Soma H, Yoshida K, Mukaida T, Tabuchi Y |title=Morphologic changes in the hypertensive placenta |journal=Contrib Gynecol Obstet |volume=9 |issue= |pages=58–75 |year=1982 |pmid=6754249 |doi= |url=}}</ref>
===General===
*Enlarged endothelial cells - fetal capillaries.
Associated pathologic changes:<ref name=pmid6754249>{{cite journal |author=Soma H, Yoshida K, Mukaida T, Tabuchi Y |title=Morphologic changes in the hypertensive placenta |journal=Contrib Gynecol Obstet |volume=9 |issue= |pages=58–75 |year=1982 |pmid=6754249 |doi= |url=}}</ref>
*Atherosis of the spiral arteries - placental bed (maternal).
 
Associated changes:<ref name=pmid6754249/>
*Placental infarcts.  
*Placental infarcts.  
*Increased syncytial knots.
*Increased syncytial knots.
Line 549: Line 707:
*Thickening of the trophoblastic basement membrane.
*Thickening of the trophoblastic basement membrane.


===Hypertrophic decidual vasculopathy===
===Microscopic===
Features:<ref name=pmid18641412>{{Cite journal | last1 = Roberts | first1 = DJ. | last2 = Post | first2 = MD. | title = The placenta in pre-eclampsia and intrauterine growth restriction. | journal = J Clin Pathol | volume = 61 | issue = 12 | pages = 1254-60 | month = Dec | year = 2008 | doi = 10.1136/jcp.2008.055236 | PMID = 18641412 }}</ref>
Features:<ref name=pmid6754249>{{cite journal |author=Soma H, Yoshida K, Mukaida T, Tabuchi Y |title=Morphologic changes in the hypertensive placenta |journal=Contrib Gynecol Obstet |volume=9 |issue= |pages=58–75 |year=1982 |pmid=6754249 |doi= |url=}}</ref>
*Mild or moderate:
*Enlarged endothelial cells - fetal capillaries.  
*#Perivascular inflammatory cells.
*Atherosis of the spiral arteries - placental bed (maternal).
*#+/-Vascular thrombosis.
*#Smooth muscle hypertrophy.
*#Endothelial hyperplasia.
*#*Above two lead to narrowing of the decidual spiral arteries<ref>AFIP - Placental Pathology. P.122. ISBN: 1-881041-89-1. 2004.</ref> -- '''key feature'''.
*Severe:<ref name=pmid18641412/>
*#Atherosis of maternal blood vessels.
*#*Foamy macrophages within vascular wall.
*#Fibrinoid necrosis of vessel wall (amorphous eosinophilic material vessel wall).


General:
Notes:
*Seen in intrauterine growth restriction (IUGR).
*One should look for the changes in the membrane roll, not the maternal surface.<ref>Sherman, C. 7 February 2011.</ref>


Images:
Images:
*[http://commons.wikimedia.org/wiki/File:Hypertrophic_decidual_vasculopathy_intermed_mag.jpg HDV - intermed. mag. (WC)].
*[http://www.pathxchange.org/case/19711 Pregnancy-induced hypertension (pathxchange.org)].
*[http://commons.wikimedia.org/wiki/File:Hypertrophic_decidual_vasculopathy_low_mag.jpg HDV - low mag. (WC)].
 
==Hypertrophic decidual vasculopathy==
:[[AKA]] ''decidual vasculopathy''.
{{Main|Hypertrophic decidual vasculopathy}}


==HELLP syndrome==
==HELLP syndrome==
{{Main|HELLP syndrome}}
==Malaria==
{{Main|Malaria}}
===General===
===General===
*Diagnosed clinically.
*Uncommon in Canada.
*Pathologically not the same as ''severe preclampsia''.<ref name=pmid18362224>{{cite journal |author=Vinnars MT, Wijnaendts LC, Westgren M, Bolte AC, Papadogiannakis N, Nasiell J |title=Severe preeclampsia with and without HELLP differ with regard to placental pathology |journal=Hypertension |volume=51 |issue=5 |pages=1295–9 |year=2008 |month=May |pmid=18362224 |doi=10.1161/HYPERTENSIONAHA.107.104844 |url=}}</ref>
*May lead to fetal demise.
 
Definition:
*'''H''' = hemolysis.
*'''EL''' = elevated liver enzymes.
*'''LP''' = low platelets.


===Microscopic===
===Microscopic===
Features:<ref name=pmid7966086>{{cite journal |author=Ornstein MH, Rand JH |title=An association between refractory HELLP syndrome and antiphospholipid antibodies during pregnancy; a report of 2 cases |journal=J. Rheumatol. |volume=21 |issue=7 |pages=1360–4 |year=1994 |month=July |pmid=7966086 |doi= |url=}}</ref>
Feature:
*Thrombotic microangiopathic vasculopathy.
*[[RBC]]s with basophilic dots ~1-2 micrometres.
**In essence: severe ''hypertrophic decidual vasculopathy''. (???)


====Image====
<gallery>
Image:Maternal_malaria_placenta_-_very_high_mag.jpg | Maternal malaria - very high mag. (WC)
</gallery>
=Tumours=
=Tumours=
{{main|Gestational trophoblastic disease}}
{{main|Gestational trophoblastic disease}}


==Chorangioma==
==Chorangioma==
{{Main|Chorangioma}}
==Chorangiomatosis==
===General===
===General===
*[[Hamartoma]]-like growth in the placenta consisting of [[blood vessel]]s.<ref name=pmid20594143>{{cite journal |author=Amer HZ, Heller DS |title=Chorangioma and related vascular lesions of the placenta--a review |journal=Fetal Pediatr Pathol |volume=29 |issue=4 |pages=199–206 |year=2010 |pmid=20594143 |doi=10.3109/15513815.2010.487009 |url=}}</ref>
Associated with:
*Preeclampsia.
*[[IUGR]].


===Epidemiology===
===Gross===
*Often benign.
*Multiple tan nodules.
*May be association with:
**Fetal maternal haemorrhage.
**Hydrops.
**[[IUGR]].


===Microscopy===
===Microscopic===
Features:
Features:
*Mass of capillaries.
*Multiple chorangiomas - the difference between chorangioma and chorangiomatosis is not well defined.<ref>URL: [http://path.upmc.edu/cases/case655/dx.html http://path.upmc.edu/cases/case655/dx.html]. Accessed on: 28 January 2012.</ref>


Image:
Images:
*[http://commons.wikimedia.org/wiki/File:Chorangioma_-_intermed_mag.jpg Chorangioma (WC)].
*[http://path.upmc.edu/cases/case655.html Chorangiomatosis - several images (upmc.edu)].
 
==Chorangiosis==
{{Main|Chorangiosis}}
 
=Other=
==Fetus papyraceus==
*May be spelled ''foetus papyraceus''.
*[[AKA]] ''fetus compressus''.
{{Main|Fetus papyraceus}}
 
==Placental mesenchymal dysplasia==
*Abbreviated ''PMD''.
{{Main|Placental mesenchymal dysplasia}}
 
=Placental cysts and pseudocysts=
Types:<ref name=Ref_Placenta219-220>{{Ref Placenta|219-220}}</ref>
*Amnionic epithelial inclusion cyst (amniotic cyst).
*[[Epidermal inclusion cyst]] - lined by keratinized squamous epithelium.
*Chorionic cyst ([[AKA]] chorionic pseudocyts).
*Cell island cyst.
 
Other considerations:<ref name=pmid12054300>{{Cite journal  | last1 = Brown | first1 = DL. | last2 = DiSalvo | first2 = DN. | last3 = Frates | first3 = MC. | last4 = Davidson | first4 = KM. | last5 = Genest | first5 = DR. | title = Placental surface cysts detected on sonography: histologic and clinical correlation. | journal = J Ultrasound Med | volume = 21 | issue = 6 | pages = 641-6; quiz 647-8 | month = Jun | year = 2002 | doi =  | PMID = 12054300 }}</ref>
*Hematoma.
*Fibrin-lined pseudocyst.
 
General:<ref name=pmid12054300/>
*Usually good outcome.
*Large cysts (>4.5 cm) or multiple cysts (>3) are associated with [[IUGR]].
 
Images:
*[http://www.jultrasoundmed.org/content/21/6/641/F5.expansion.html Subchorionic cysts (jultrasoundmed.org)].<ref name=pmid12054300/>


=See also=
=See also=
Line 609: Line 796:
*[[Endometrium]].
*[[Endometrium]].
*[[Pregnancy]].
*[[Pregnancy]].
*[[Gestational trophoblastic disease]].
*[[TORCH infections]].


=References=
=References=
{{reflist|2}}
{{reflist|2}}


[[Category:Gynecology]]
=Recommended reading=
*{{cite journal |author=Langston C, Kaplan C, Macpherson T, ''et al.'' |title=Practice guideline for examination of the placenta: developed by the Placental Pathology Practice Guideline Development Task Force of the College of American Pathologists |journal=Arch. Pathol. Lab. Med. |volume=121 |issue=5 |pages=449–76 |year=1997 |month=May |pmid=9167599 |doi= |url=}}
*{{cite book |author= Baergen, Rebecca N. |title=[http://www.amazon.com/Manual-Benirschke-Kaufmanns-Pathology-Placenta/dp/0387220895/ref=sr_1_1?ie=UTF8&qid=1297169019&sr=8-1 Manual of Benirschke and Kaufmann's Pathology of the Human Placenta] |publisher=Springer |location= |year=2005 |pages= {{{1|}}} |edition=1st |isbn=978-0387220895 |oclc= |doi= |accessdate=}}


=External links=
=External links=
*[http://emedicine.medscape.com/article/262470-overview Cord complications (emedicine.medscape.com)].
*[http://emedicine.medscape.com/article/262470-overview Cord complications (emedicine.medscape.com)].
*[http://www.palpath.com/MedicalTestPages/placenta2.htm Placenta notes (palpath.com)].
[[Category:Placenta]]

Latest revision as of 15:27, 10 May 2018

A placenta (fetal aspect) with attached umbilical cord. (WC/Asturnut)

The placenta feeds the developing baby, breathes for it and disposes of its waste.

The organ is one that seems to be left behind; at least one review suggests it isn't done so well by general pathologists.[1]

Placental pathology redirects to this article.

Clinical

Examination of the placenta

  • Most placentas are not examined by a pathologist.

Indications for exam by pathology

Some indications for exam by a pathologist:

  • Abnormalities in the:
    1. Fetus:
      • Bad fetal outcome.
      • Suspected or known congenital abnormalities or chromosomal abnormalities.
      • IUGR.
    2. Mother:
      • Infection/suspected infection.
      • Pre-term labour.
      • Maternal disease (e.g. SLE, coagulopathy).
      • Complicated pregnancy (preclampsia, pregnancy induced hypertension, gestational diabetes).
    3. Placenta:
      • Unusual gross characteristics.[2]

A more detailed list is given by Hargitai et al.[3] and Chang.[4]

Most common

Most common reasons for submitting a placenta to pathology:[5]

  1. Prematurity.
  2. PROM / possible chorioamnionitis.
  3. Multiple gestation.

Bleeding in late pregnancy

DDx of bleeding in late pregnancy:

Clinical screening tests

  • PAPP-A - low values seen in aneuploidy.[6]

Abbreviations

  • C/S = Caesarean section.
  • LSCS = lower segment C-section.
  • FTP = failure to progress.
  • PROM = premature rupture of membranes.
  • PPROM = preterm premature ruptures of membranes.
  • IUGR = intrauterine growth restriction.
  • IOL = induction of labour.

Normal histology

Villi

This is dealt with in a separate article that also covers the types of trophoblast (cytotrophoblast, syncytiotrophoblast, intermediate trophoblast).

Cord

Omphalomesenteric duct remnant

  • AKA vitelline duct.
  • Benign embryologic remnant.

Features:

  • Duct with benign looking cuboidal epithelium.

Allantoic duct remnant

  • Benign embryologic remnant.

Features:

  • Duct with benign looking flat epithelium.

Vitelline artery remnant

Features:

  • Small artery in the cord.

Membranes

Fetus to mother:

  • Amnion - thin layer: one cell layer, basement membrane, connective tissue.
  • Cleft - artifactual - empty space.
  • Chorion - vascular.
  • Decidua (maternal tissue) - may contain obsolete chorionic villi; place to look for hypertensive changes.

Amnion

General:

  • Next to fetus, surrounds amniotic fluid, avascular.

Characteristics:

  • Characterized by a single layer of cells.[7]
    • Cuboidal/squamoid shape.
    • Eosinophilic cytoplasm.
    • Central nucleus.
  • Squamous metaplasia may be seen at cord insertion.
  • Basement membrane.
  • 'Compact layer'.[7]
  • 'Fibroblastic layer'.[7]

Chorion

General:

  • Surrounds amnion.

Characteristics:

  • Layers:[8]
    • 'Reticular layer' - cellular (inner aspect).
    • 'Pseudo-basemement membrane'.
    • 'Outer trophoblastic layer'.
  • Has blood vessels.
  • Opposed to "trophoblastic X cells" on side opposite of amnion.[7]
    • Beneath of the "trophoblastic X cells" is decidua (mnemonic NEW = nucleus central, eosinophilic, well-defined cell border), which is maternal tissue.

Note:

  • Fibrin deposition may be found deep to the chorion - known as subchorionic fibrin deposition.
    • Gross: subchorionic, white/yellow, laminated, classically has a triangular-shape with the base of triangle parallel to fetal aspect of disc.
      • Arises due to localized stasis of the inter-villous maternal blood.
    • Focal small deposits are considered to be a normal finding - seen in ~15% of cases.[9][10]

Image:

Common terms

  • Chorionic plate - fetal aspect of placenta.
  • Basal plate - maternal aspect of placenta.
    • Has extravillous trophoblast.
    • Place to look for maternal vessels.

Grossing

This is often very quick. The gross is quite important, as some things cannot be diagnosed microscopically.

General

  • Dimensions:
    • Disc.
    • Length of cord, diameter of cord.
    • Accessory lobes - dimensions.
      • Two lobes of equal size + cord arises in between = bilobate placenta.
  • Mass (weight).
    • Should be done 'trimmed' (cord cut-off, membrane cut-off).
    • Should be done when placenta is "fresh", i.e. not fixed -- as mass tables are based on fresh state.
  • Umbilical cord
    • Attachment.
      • Location: central, eccentric, marginal.
        • Marginal attachment assoc. with hypertension[11]
      • Membranous or velamentous (veil-like) insertion.
        • Vessels separate/branch prior to reaching placental disc.
      • Furcate insertion - blood vessels separate before reaching placenta disc/not surrounded by Wharton's jelly - vessels more exposed to trauma (risk for vasa previa).
    • Knots (false vs. true).
      • False knots are nothing to worry about -- look like a knot but aren't really one.
    • Twisting/coiling - 1-3 coils/10 cm is normal.
    • Number of vessels.
      • Normal: 2 arteries, 1 vein.
  • Membranes - shiny & translucent - normal (green, opaque/dull - chorioamnionitis).
    • Attachment (insertion): marginal (normal), circummarginate (inside edge), circumvallate (folding on self).
    • Site of rupture - if obvious; low point of rupture suggests low-lying placenta.
  • Placental disc.
    • Fetal surface - normal is shinny.
      • Dull in chorioamnionitis.
    • Maternal surface
      • Are the cotyledons intact?
      • Adherent clot?
    • Parenchyma - after sectioning:
      • White vs. red nodules.

Notes:

Sections

  1. Cord two sections.
  2. Membranes (rolled), two rolls or more.[12]
  3. Cord at insertion + disc.
  4. Placenta - full thickness (maternal and fetal surface).
    • Sections should not be taken at the margin of the disc.

Placental membranes

Appearance:[13]

Placental mass

It is considered routine to obtain a mass for the placenta. This is usually done when the placenta is fresh and with the membranes and cord trimmed, as most tables of placental mass were created with these parameters.

Placental mass by gestational age:[15]

Gest. Age/Percentile 25% 50% 75%
32 weeks 275 g 318 g 377 g
36 weeks 369 g 440 g 508 g
40 weeks 440 g 501 g 572 g

Linear regression - placental mass-gestational age

Based on the table in the AFIP book[16] one can generate the following regression lines:

50% 10% 90%
slope (g/week) 21.58088235 19.70588235 25.40196078
y-intercept (g) -357.4558824 -397.2352941 -366.7254902
Pearson (r) 0.988670724 0.988268672 0.982206408

placental mass = slope x gestational age + intercept

What to remember...

Extrapolated from the linear regression (see above):

  • 50% at term = 500 grams.
  • 50% at 26 weeks = 200 grams.
  • The change in mass/week is approximately linear and equal to 300 grams / 14 weeks ~ 20 grams/week.
  • The spread in mass between 10% and 90%, crudely estimated, is 200 grams (for GA=26-40).

Notes:

  • Is it required?
    • Sebire and Fox have advocated abandoning the practise of obtaining a placental mass, due to the large number of uncontrolled variables inherent in these measures. Instead, they have advocated using mushy descriptors such as "small", "average" and "large", which require experience in examining the organ.[17]
      • In the context of quality, a measure (even if somewhat flawed) is probably more reproducible and objective than arbitrary descriptors which require experience and a continuing case volume to calibrate.

Placentomegaly

  • AKA large placenta.

Associations:[18]

Lame causes of a heavy placenta:

  • Dates wrong - error in determining the estimated date of confinement.
  • Adherent blood clot.

Comment:

  • Most of causes seem to have one thing in common:
    • There is a decreased oxygen delivery to the fetus.

Sign out

PLACENTA, UMBILICAL CORD AND FETAL MEMBRANES, CESAERIAN SECTION:
- LARGE PLACENTA (819 GRAMS -- TRIMMED, POST-FIXATION WEIGHT).
- FETAL MEMBRANES WITHIN NORMAL LIMITS.
- THREE VESSEL UMBILICAL CORD WITHIN NORMAL LIMITS.
- PLACENTAL DISC WITH THIRD TRIMESTER VILLI.

Placental growth restriction

  • AKA placenta small for gestational age.
  • Small placenta redirects here.

Associations:

  • Maternal vascular disease, e.g. hypertension.
  • Fetal malformations.

Sign out

PLACENTA, UMBILICAL CORD AND FETAL MEMBRANES, BIRTH:
- PLACENTA SMALL FOR GESTATIONAL AGE (160 GRAMS -- TRIMMED, POST-FIXATION WEIGHT).
- THREE VESSEL UMBILICAL CORD WITHIN NORMAL LIMITS.
- FETAL MEMBRANES WITHIN NORMAL LIMITS.
- PLACENTAL DISC WITH THIRD TRIMESTER VILLI WITH:
-- OLD CENTRAL TRANSMURAL INFARCT (1.7 CM MAXIMAL DIMENSION).

COMMENT:
The 10th percentile placental mass (pre-fixation) for 34 weeks and 2 days is approximately 390 grams.

Overview of placental pathology

Approach

The pathology of the placenta is diverse and is not easy to group.

It terms of remembering things. It is probably easiest to take a combined anatomical, etiologic and morphologic approach.

Anatomical basis:

  • Cord.
  • Membranes.
  • Disc.

Etiologic:

  • Congential.
  • Infectious.
  • Neoplastic.
  • Endocrine.
  • Trauma.
  • Vascular.
  • Degenerative.
  • Autoimmune.
  • Toxic.
  • Idiopathic.

Compartmental:

  • Vasculature.
  • Membranes.
  • Parenchyma:
    • Maternal part (decidua).
    • Fetal part (villi, cord).

Common entities/diagnoses

Sign out

What should be commented on...

  • Placenta:
    • Maturity of villi (2nd or 3rd trimester).
    • Infarction?
      • Subchorionic less important than maternal aspect.
      • Peripheral aspect of placental disc less important than central region of disc.
    • Blood vessels.
      • Maternal.
      • Fetal.
  • Membranes.
  • Cord:
    • 3 vessel?
    • Vasculitis/inflammation?

Mnemonic: chorio, cord, vessels, villi (maturity, infarction).

Normal placenta

PLACENTA, UMBILICAL CORD AND FETAL MEMBRANES, BIRTH:
- THREE VESSEL UMBILICAL CORD WITHIN NORMAL LIMITS.
- FETAL MEMBRANES WITHIN NORMAL LIMITS.
- PLACENTAL DISC WITH THIRD TRIMESTER VILLI WITHIN NORMAL LIMITS.

C-section

PLACENTA, UMBILICAL CORD AND FETAL MEMBRANES, CAESAREAN SECTION:
- THREE VESSEL UMBILICAL CORD WITHIN NORMAL LIMITS.
- FETAL MEMBRANES WITHIN NORMAL LIMITS.
- PLACENTAL DISC WITH THIRD TRIMESTER VILLI WITHIN NORMAL LIMITS.

Cord pathology

Two vessel umbilical cord

  • AKA two vessel cord.
  • AKA single umbilical artery.

Insertion

Marginal insertion

Definition:

  • The umbilical cord is attached to the placental disc at its margin.

Prevalence:

  • Approximately 12% of placentas.[21]

Relevance:

  • None according to WMSP.[21]
    • In theory, the cord, dependent on its relation to the internal os, is at greater risk of injury (leading to vasa previa) and compression (fetal hypoxia). A retrospective study found cord position in relation to the internal os is predictive for vasa previa.[22]

Velamentous insertion

Definition:

  • The umbilical cord inserts into the fetal membranes.[21]
    • The vessels are not protected by Wharton's jelly.
      • Wharton's jelly = the connective tissue surrounding the vessels in the cord.

Details:[21]

  • 3/4 of the time the vessel also branch; in the remaining 1/4 the vessels stay together.

Relevance:

  • Increased risk of vasa previa.[22]

Sign out

PLACENTA, UMBILICAL CORDS AND FETAL MEMBRANES, BIRTH:
- THREE VESSEL UMBILICAL CORD WITH A VELAMENTOUS INSERTION, OTHERWISE WITHIN NORMAL LIMITS.
- FETAL MEMBRANES WITHIN NORMAL LIMITS.
- PLACENTAL DISC WITH THIRD TRIMESTER VILLI WITHIN NORMAL LIMITS.

Umbilical knot

  • AKA umbilical cord knot.
  • AKA cord knot.
  • AKA true knot.

General

Gross

Work-up:[24]

  • Diameter measures and colour on both sides of the knot.
  • Knot should be untied to assess for deformation of Wharton's jelly.
  • Sections from both sides of the knot - to look for thrombi.

Note:

  • False knots (large diameter - focally) are common - they cannot be untied.

Microscopic

Features:

  • +/-Thrombi.
    • Fibrin deposition.
  • +/-Lines of Zahn.

Images:

Coiling

  • Hypo- and hypercoiling are both considered problematic.[21]
    • Normal: 1-3 coils/10 cm.[25]
  • Associated with cord stricture, which is usu. at the fetal end of the cord.[26]

Notes:

  • There is little uniformity in how coiling is assessed in the medical literature - though 10% and 90% are considered the cut-points for normal.[27]
    • What are the 10% and 90% cut-points? They are not given in WMSP. UT access to a journal article[28] that might have it is screwed-up.

Cord hematoma

Features:[26]

  • Rare ~ 1/5500.
  • Mortality ~50% is severe.

Membranes

Amnion nodosum

Placental meconium

Squamous metaplasia of the amnion

General

  • Benign common finding thought to be of no clinical significance.[29]
  • Needs to be separated from amnion nodosum - important.[31]

Gross

Features:[32]

  • White (or yellow) plaques - irregular outline.

DDx:

Images:

Microscopic

Features:[32]

  • Dense, paucicellular (pink) compact keratin - key feature.

Image:

Circumvallate placenta

  • AKA circumvallate insertion of the membranes.

General

Note:

  • Membranes usually attach to the edge of the placenta.

Gross

  • Fetal membranes attach to the fetal surface of the placenta away from the margin of the placental disc.

Classification:

  • Partial - not circumferential.
  • Complete.

DDx:

Images:

Twin placentas

These are often submitted... even if they are normal. In these specimens, usually, the chorion is the key.

It covers:

  • Monozygotic vs. dizygotic twins.
  • Twin-to-twin transfusion syndrome.

Placental disc

Villous edema

General

  • Non-specific finding.
  • Reported in associated with congenital adrenal hyperplasia for the stem villi.[35]

Microscopic

Features:

  • "Swiss chesse-like" appearance / bubbly appearance.
  • Usually patchy and focal.

Note:

  • Cistern formation is reported in the stem villi in association with congenital adrenal hyperplasia.[35]

DDx:

Image:

Placental villous immaturity

Villous hypoplasia

  • AKA terminal villus deficiency.[37]

Diseases of the placental attachment

Placenta creta

Includes placenta accreta, placenta increta, and placenta percreta.

Placental abruption

Inflammatory pathologies

Overview of infections

General:[38]

Types

By site:[38]

  • Fetal membranes: chorioamnionitis, membranitis.[39]
  • Umbilical cord: funisitis.
  • Placenta: placentitis, villitis.

Membranitis

Chorionitis redirects here.

General

Microscopic

Features:

  • PMNs in the decidua.
  • +/-PMNs in subamniotic tissue.
  • +/-Necrosis in decidua or chorion/subamniotic tissue.

Note:

DDx:

Grading membranitis

Sternberg:[39]

  1. PMNs - decidua only.
  2. PMNs - in subamniotic tissue.
  3. 1 or 2 + necrosis in decidua or chorion/subamniotic tissue.

Sign out

PLACENTA, UMBILICAL CORD AND FETAL MEMBRANES, CESAERIAN SECTION:
- FETAL MEMBRANES WITH CHORIONITIS.
- THREE VESSEL UMBILICAL CORD WITH VASCULITIS.
- PLACENTAL DISC WITH THIRD TRIMESTER VILLI.

Waffle

PLACENTA, UMBILICAL CORD AND FETAL MEMBRANES, BIRTH:
- FETAL MEMBRANES WITH MECONIUM-LADEN MACROPHAGES AND ABUNDANT DECIDUAL NEUTROPHILS
  SUSPICIOUS FOR EARLY CHORIONITIS.
- PLACENTAL DISC WITH THIRD TRIMESTER VILLI.
- THREE VESSEL UMBILICAL CORD WITHIN NORMAL LIMITS.

Chorioamnionitis

Umbilical cord vasculitis

Funisitis

  • Inflammation of Wharton's jelly - the connective tissue of the umbilical cord.

Acute villitis

Villitis of unknown etiology

Chronic intervillitis

General

  • Rare.
  • Massive chronic intervillitis - associated IUGR, spontaneous abortion, perinatal fetal death.[42]
  • Recurs.

Microscopic

Features:[41][42]

  • Intervillous inflammatory cells:
    • Lymphocytes.
    • Histiocytes.
  • Fibrinoid deposition.

Images

Chronic deciduitis

  • AKA plasma cell deciduitis.

Placental infarction

True infarcts

Perivillous fibrin deposition

  • Abbreviation PFD.

General

  • Thought to be an immunologic problem - resulting in platelet activation and fibrin deposition.[43]
  • May be associated with diabetes mellitus.[44]

Gross

  • Pale (white).
  • Firm.
  • White fibrous sepatae.

Microscopic

Features:

  • Acellular eosinophilic material around formed villi.
  • Obliteration of intervillous space.
    • Intervillous distance increased vis-a-vis normal - key feature.

Notes:

  • Nuclei of villi are usually preserved.
  • Villi may have secondary infarction, i.e. there may be nuclear destruction (karyolysis, karyorrhexis, pyknosis).

DDx:

Images:

Sign out

Thrombi

PLACENTA, UMBILICAL CORD AND FETAL MEMBRANES, BIRTH:
- THREE VESSEL UMBILICAL CORD WITHIN NORMAL LIMITS.
- FETAL MEMBRANES WITHIN NORMAL LIMITS.
- PLACENTAL DISC WITH THIRD TRIMESTER VILLI AND THREE LARGE INTERVILLOUS 
THROMBI (BLOCKS A7-A9).

Maternal floor infarction

  • Abbreviated MFI.
  • Formally placental maternal floor infarction.
  • AKA massive perivillous fibrin deposition.[45]

Fetal disease

Fetal thrombotic vasculopathy

  • Abbreviated FTV.
  • A large number of terms are used for this including:[46]
    • Fibrinous vasculosis.
    • Fibromuscular sclerosis.
    • Fetal artery stem thrombosis.
  • The multitude of terms reflects the confusion about this finding and that it has numerous etiologies.[46]

Hemorrhagic endovasculitis

  • Abbreviated HEV.

General

  • Associated with stillbirth.[47]

Microscopic

Features:[48]

  • Walls of the (fetal) placental blood vessels (in the villi) are disrupted.
  • +/-Intraluminal necrotic debris.
  • RBC fragmentation.

Maternal disease

Hypertensive changes

General

Associated pathologic changes:[49]

  • Placental infarcts.
  • Increased syncytial knots.
  • Hypovascularity of the villi.
  • Cytotrophoblastic proliferation.
  • Thickening of the trophoblastic basement membrane.

Microscopic

Features:[49]

  • Enlarged endothelial cells - fetal capillaries.
  • Atherosis of the spiral arteries - placental bed (maternal).

Notes:

  • One should look for the changes in the membrane roll, not the maternal surface.[50]

Images:

Hypertrophic decidual vasculopathy

AKA decidual vasculopathy.

HELLP syndrome

Malaria

General

  • Uncommon in Canada.
  • May lead to fetal demise.

Microscopic

Feature:

  • RBCs with basophilic dots ~1-2 micrometres.

Image

Tumours

Chorangioma

Chorangiomatosis

General

Associated with:

Gross

  • Multiple tan nodules.

Microscopic

Features:

  • Multiple chorangiomas - the difference between chorangioma and chorangiomatosis is not well defined.[51]

Images:

Chorangiosis

Other

Fetus papyraceus

  • May be spelled foetus papyraceus.
  • AKA fetus compressus.

Placental mesenchymal dysplasia

  • Abbreviated PMD.

Placental cysts and pseudocysts

Types:[52]

  • Amnionic epithelial inclusion cyst (amniotic cyst).
  • Epidermal inclusion cyst - lined by keratinized squamous epithelium.
  • Chorionic cyst (AKA chorionic pseudocyts).
  • Cell island cyst.

Other considerations:[53]

  • Hematoma.
  • Fibrin-lined pseudocyst.

General:[53]

  • Usually good outcome.
  • Large cysts (>4.5 cm) or multiple cysts (>3) are associated with IUGR.

Images:

See also

References

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Recommended reading

External links