Placenta: Difference between revisions

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Mikael Häggström (talk | contribs)
Administrators, Editors, Image-reviewer, csmoderator, Interface administrators, Administrators, Upload Wizard campaign editors
7,148 edits
 
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{{Top
<noinclude>{{Top
|author1=[[User:Mikael Häggström|Mikael Häggström]]
|author1=[[User:Mikael Häggström|Mikael Häggström]]
|author2=
|author2=
}}
}}
{{Comprehensiveness}}
{{Comprehensiveness}}
 
</noinclude>
==Gross processing==
==Gross processing==
*Determine the '''shape''' of the placenta
*Determine the '''shape''' of the placenta
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*Examine the '''umbilical cord'''
*Examine the '''umbilical cord'''
:*Measure the '''distance''' between the insertion point and the nearest placental margin
:*Measure the '''distance''' between the insertion point and the nearest placental margin
:*Measure the cord '''length''' and give proximal and distal diameter. In placental pathology, the ''proximal'' umbilical cord refers to the segment closest to the placenta, and ''distal'' is the segment closest to the fetus.<ref group=notes>In contrast, in embryology and fetal medicine, the ''proximal'' umbilical cord refers to the segment closest to the fetus:<br>- {{cite journal| author=Wyburn GM| title=The formation of the umbilical cord and the umbilical region of the anterior abdominal wall. | journal=J Anat | year= 1939 | volume= 73 | issue= Pt 2 | pages= 289-310.9 | pmid=17104757 | doi= | pmc=1252509 | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=17104757  }}<br>{{cite web|url=https://medicine.yale.edu/obgyn/kliman/placenta/research/Umbilical%20Cord%20EOR_163162_284_18220_v1.pdf|title=The Umbilical Cord (from The Encyclopedia of Reproduction)|author=Harvey J. Kliman, M.D., Ph.D.|website=Yale School of Medicine|date=2006-10-29}}</ref>
:*Measure the cord '''length''' and give proximal and distal diameter. In placental pathology, the ''proximal'' umbilical cord refers to the segment closest to the placenta, and ''distal'' is the segment closest to the fetus.<ref group=note>In contrast, in embryology and fetal medicine, the ''proximal'' umbilical cord refers to the segment closest to the fetus:<br>- {{cite journal| author=Wyburn GM| title=The formation of the umbilical cord and the umbilical region of the anterior abdominal wall. | journal=J Anat | year= 1939 | volume= 73 | issue= Pt 2 | pages= 289-310.9 | pmid=17104757 | doi= | pmc=1252509 | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=17104757  }}<br>{{cite web|url=https://medicine.yale.edu/obgyn/kliman/placenta/research/Umbilical%20Cord%20EOR_163162_284_18220_v1.pdf|title=The Umbilical Cord (from The Encyclopedia of Reproduction)|author=Harvey J. Kliman, M.D., Ph.D.|website=Yale School of Medicine|date=2006-10-29}}</ref>
:*Count the number of '''vessels''' away from the insertion
:*Count the number of '''vessels''' away from the insertion
*'''Weigh''' the trimmed disk, after having trimmed away the cord and membranes, and after having removed excess amounts of loose retroplacental blood clots over the maternal surface.
*'''Weigh''' the trimmed disk, after having trimmed away the cord and membranes, and after having removed excess amounts of loose retroplacental blood clots over the maternal surface.
*Examine the '''fetal surface''' (chorionic plate):
*Examine the '''fetal surface''' (chorionic plate):
:*Note its '''color'''  
:*Note its '''color''', in particular if it is green (often faint and tan-green, brown-green to yellow-green (which indicates '''[[Meconium histocytosis|meconium staining]]''').
:*Look for any '''pathologies''' including granular excrescences, subchorionic fibrin or subamniotic hemorrhage  
:*Look for any '''pathologies''' including granular excrescences, subchorionic fibrin or subamniotic hemorrhage  
:*Look at the integrity and extent of the '''vasculature''', including any thrombosis and traumatic damage  
:*Look at the integrity and extent of the '''vasculature''', including any traumatic damage. Also palpate the vasculature for any thrombosis. If a thrombus is grossly found for a live birth, the baby may have thrombosis, so the finding must immediately be reported to the clinician in care of the baby.
*Examine the '''maternal surface''' (basal plate) for completeness, adherent blood clots, depressions, calcifications and fibrin
*Examine the '''maternal surface''' (basal plate) for completeness, adherent blood clots, depressions, calcifications and fibrin
*Take a '''membrane roll''' and '''cord sections''', before sectioning the placenta
*Take a '''membrane roll''' and '''cord sections''', before sectioning the placenta
*With the fetal surface down on the cutting board, '''cut''' the placenta at 1cm intervals so that it can be reconstructed.
*With the fetal surface down on the cutting board, '''cut''' the placenta at 1cm intervals so that it can be reconstructed.
[[File:Gross pathology of severe intervillositis.jpg|thumb|190px|center|Placental tissue after cutting, here showing severe intervillositis, with dark red and soggy tissue.]]
<gallery mode=packed heights=190px>
File:Making a fetal membrane roll.jpg|thumb|Making a fetal membrane roll.
File:Gross pathology of severe intervillositis.jpg|Placental tissue after cutting, here showing severe intervillositis, with dark red and soggy tissue.
</gallery>
*'''Palpate''' the parencyhmal sections for areas of induration.
*'''Palpate''' the parencyhmal sections for areas of induration.
*Note the '''color''' of the parenchyma and describe any pale areas, cysts, infarcts (estimate total amount of infarcted tissue), thrombi, increased fibrin and calcifications
*Note the '''color''' of the parenchyma and describe any pale areas, cysts, thrombi, increased fibrin, calcifications and infarcts. For possible infarcts, estimate the total amount of infarcted tissue as a percentage of the placental volume. Infarction is clinically significant if it involves at least 5-10% of the placental volume.
[[File:Gross pathology of placental disorders.jpg|thumb|520px|center|Gross pathology of placental disorders.<ref name="ChenZhang2020">{{cite journal|last1=Chen|first1=Yukun|last2=Zhang|first2=Zhuomin|last3=Wu|first3=Chenyan|last4=Davaasuren|first4=Dolzodmaa|last5=Goldstein|first5=Jeffery A.|last6=Gernand|first6=Alison D.|last7=Wang|first7=James Z.|title=AI-PLAX: AI-based placental assessment and examination using photos|journal=Computerized Medical Imaging and Graphics|volume=84|year=2020|pages=101744|issn=08956111|doi=10.1016/j.compmedimag.2020.101744}}<br>- Fig 5- available via license: Creative Commons Attribution 4.0 International.</ref>]]
[[File:Gross pathology of placental disorders.jpg|thumb|520px|center|Gross pathology of placental disorders.<ref name="ChenZhang2020">{{cite journal|last1=Chen|first1=Yukun|last2=Zhang|first2=Zhuomin|last3=Wu|first3=Chenyan|last4=Davaasuren|first4=Dolzodmaa|last5=Goldstein|first5=Jeffery A.|last6=Gernand|first6=Alison D.|last7=Wang|first7=James Z.|title=AI-PLAX: AI-based placental assessment and examination using photos|journal=Computerized Medical Imaging and Graphics|volume=84|year=2020|pages=101744|issn=08956111|doi=10.1016/j.compmedimag.2020.101744}}<br>- Fig 5- available via license: Creative Commons Attribution 4.0 International.</ref>]]
If you see a '''true knot''' (rather than "false knots" which are merely bulges or protuberances that may look like knots), report whether the diameter of the cord is significantly different before versus after the knot (which is a sign of constriction caused by the knot).


===Tissue selection===
===Tissue selection===
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*Placental section including '''maternal surface''' (full thickness if possible)
*Placental section including '''maternal surface''' (full thickness if possible)
*Any '''lesions''' or '''abnormalities'''
*Any '''lesions''' or '''abnormalities'''
Avoid taking placental sections near the margin
Avoid taking placental sections near the margin. {{Moderate-begin}}If transported or processed together with other cases, put the placental in thin-mesh cassettes or tissue bags to limit contamination{{Moderate-end}}.<ref group=note>Chorionic villi are promiscuous contaminants of other tissues, and may cause a false positive finding for a cassette containing products of conception.<br>- {{cite journal| author=Carll T, Fuja C, Antic T, Lastra R, Pytel P| title=Tissue Contamination During Transportation of Formalin-Fixed, Paraffin-Embedded Blocks. | journal=Am J Clin Pathol | year= 2022 | volume= 158 | issue= 1 | pages= 96-104 | pmid=35195717 | doi=10.1093/ajcp/aqac014 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=35195717  }} </ref>
 
Example report:
{|class=wikitable
| Container A. Labeled "bladder tumor". The specimen is received in formalin and consists of multiple fragments of tan-gray, friable soft tissue measuring about __ x __ x __ cm in aggregate. The specimen is entirely submitted for microscopic examination in __ cassettes.
|}


===Gross report===
===Gross report===
[[File:Placenta weight by gestational age.svg|thumb|Placenta weight by gestational age.]]
[[File:Placenta weight by gestational age.svg|thumb|340px|Placenta weight by gestational age.]]
Example in a normal case:
Example in a normal case:
{|class=wikitable
{|class=wikitable
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==Microscopic examination==
==Microscopic examination==


*Look for '''inflammation''', especially by the fetal surface in the intervillous spaces and around the fetal blood vessels.<ref group=notes>Minor inflammation in the decidua can be ignored as it doesn't have a clinical significance for the fetus.</ref>
*Look for '''inflammation''', especially by the fetal surface in the intervillous spaces and around the fetal blood vessels.
<gallery mode=packed heights=180>
<gallery mode=packed heights=200>
File:Histopathology of subchorionic intervillositis, annotated.jpg|Acute '''subchorionic intervillositis''', with neutrophils (annotated) in Langhan’s layer of fibrinoid (by the fetal surface, at the base of a chorionic villus, seen at top right).
File:Histopathology of subchorionic intervillositis, annotated.jpg|Acute '''subchorionic intervillositis''', with neutrophils (annotated) in Langhan’s layer of fibrinoid (by the fetal surface, at the base of a chorionic villus, seen at top right).
File:Insignificant intervillous neutrophils, annotated.jpg|On the other hand, a small amount of intervillous neutrophils by the fetal surface like this is insignificant.
File:Insignificant intervillous neutrophils, annotated.jpg|On the other hand, a small amount of intervillous neutrophils by the fetal surface like this is insignificant.
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File:Histopathology of acute choriodeciduitis.jpg|thumb|150px|Acute '''choriodeciduitis''', with neutrophils seen in the chorion and decidua.
File:Histopathology of acute choriodeciduitis.jpg|thumb|150px|Acute '''choriodeciduitis''', with neutrophils seen in the chorion and decidua.
</gallery>
</gallery>
*At least if there is a suspicion of '''meconium''' in the amniotic fluid (from clinical history and/or the gross exam), look for the following histopathologic signs of it:<ref>{{cite web|url=https://www.pathologyoutlines.com/topic/placentameconium.html|title=Placenta - Nonneoplastic placental conditions and abnormalities - Noninfectious - Meconium staining|website=Pathology Outlines|author=Mandolin S. Ziadie}} Topic Completed: 1 October 2011. Minor changes: 27 August 2020</ref>
*At least if there is a suspicion of '''[[meconium]]''' in the amniotic fluid (from clinical history and/or the gross exam), look for the following histopathologic signs of it:<ref>{{cite web|url=https://www.pathologyoutlines.com/topic/placentameconium.html|title=Placenta - Nonneoplastic placental conditions and abnormalities - Noninfectious - Meconium staining|website=Pathology Outlines|author=Mandolin S. Ziadie}} Topic Completed: 1 October 2011. Minor changes: 27 August 2020</ref>
<gallery mode=packed heights=180>
<gallery mode=packed heights=180>
File:Histopathology of fetal membrane edema as a sign of meconium, annotated.jpg|'''Edema'''
File:Histomathology of meconium histocytosis.jpg|The pigment-laden macrophages are presumably '''meconium'''-laden "meconiophages", the pathologic diagnosis can be termed "'''[[meconium histocytosis]]'''"
File:Histopathology of pigment-laden macrophages and epithelial vacuolation as signs of meconium, annotated.jpg|At the amniotic surface, with presumable '''meconium'''-laden "meconiophages", the pathologic diagnosis can be termed "meconium histocytosis".
</gallery>
</gallery>
'''Other relatively common findings'''
'''Other relatively common findings'''
<gallery mode=packed>
<gallery mode=packed heights=200>
File:Histology of calcification of a term placenta.jpg|'''Calcifications''', are normal in term placentas. Report if seen in a placenta younger than 36 weeks of gestational age.<ref>[https://www.researchgate.net/publication/287299495_Placental_calcification_Its_processes_and_impact_on_pregnancy Chapter 3. Placental Calcification: Its Processes and Impact on Pregnancy], {{cite book | last=Kachewar | first=Sushil | title=Calcification : processes, determinants and health impact | publisher=Nova Science Publishers, Inc | publication-place=New York | year=2013 | isbn=978-1-62618-155-7 | oclc=840507829}}</ref>
File:Histology of calcification of a term placenta.jpg|'''Calcifications''', are normal in term placentas. Report if seen in a placenta younger than 36 weeks of gestational age.<ref>[https://www.researchgate.net/publication/287299495_Placental_calcification_Its_processes_and_impact_on_pregnancy Chapter 3. Placental Calcification: Its Processes and Impact on Pregnancy], {{cite book | last=Kachewar | first=Sushil | title=Calcification : processes, determinants and health impact | publisher=Nova Science Publishers, Inc | publication-place=New York | year=2013 | isbn=978-1-62618-155-7 | oclc=840507829}}</ref>
File:Histopathology of fibrinoid necrosis of the placenta.jpg|'''[[Fibrinoid necrosis of the placenta|Fibrinoid necrosis]]'''. Only needs mention when severe {{Comprehensive-begin}}or moderate{{Comprehensive-end}}.
File:Histopathology of fibrinoid necrosis of the placenta.jpg|Villous '''[[Fibrinoid necrosis of the placenta|fibrinoid necrosis]]'''. Only needs mention when severe {{Comprehensive-begin}}or moderate{{Comprehensive-end}}.
File:Histopathology of chorangiosis.jpg|'''Chorangiosis''', an abundance of blood vessels within the chorionic villi.
File:Histopathology of chorangiosis.jpg|'''Chorangiosis''', an abundance of blood vessels within the chorionic villi.
File:Histopathology of placenta with increased syncytial knotting of chorionic villi, annotated.jpg|Increased syncytial knotting of chorionic villi, with two knots pointed out. Causes include both hypoxia and hyperoxia.<ref name="pmid17140657">{{cite journal| author=Heazell AE, Moll SJ, Jones CJ, Baker PN, Crocker IP| title=Formation of syncytial knots is increased by hyperoxia, hypoxia and reactive oxygen species. | journal=Placenta | year= 2007 | volume= 28 Suppl A | issue=  | pages= S33-40 | pmid=17140657 | doi=10.1016/j.placenta.2006.10.007 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=17140657  }} </ref>
</gallery>
</gallery>


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| {{Moderate-begin}}Placenta, <<vaginal/Caesarean>> delivery:{{Moderate-end}}<br>Third trimester placenta with term villous histology. Placental weight (__ gm), at __th percentile for gestational age. Membranes without significant histopathologic changes{{Comprehensive-begin}}, negative for chorioamnionitis{{Comprehensive-end}}. Trivascular umbilical cord, with no significant histopathologic changes{{Comprehensive-begin}}, negative for funisitis{{Comprehensive-end}}.  
| {{Moderate-begin}}Placenta, <<vaginal/Caesarean>> delivery:{{Moderate-end}}<br>Third trimester placenta with term villous histology. Placental weight (__ gm), at __th percentile for gestational age. Membranes without significant histopathologic changes{{Comprehensive-begin}}, negative for chorioamnionitis{{Comprehensive-end}}. Trivascular umbilical cord, with no significant histopathologic changes{{Comprehensive-begin}}, negative for funisitis{{Comprehensive-end}}.  
|}
|}
{{Bottom}}
 
Mild to moderate inflammation in the decidua alone can be ignored (as it is most commonly a physiological response and doesn't have a clinical significance for the fetus).
 
Example in a '''twin''' placenta:
{|class=wikitable
| Twin placenta, Caesarean section:
*Third trimester dichorionic, diamniotic twin placenta.
*Villous morphology histologically appropriate for gestational age.
*Placental weight approximately 25th percentile for gestational age.
*Two three-vessel umbilical cords.
*Negative for chorioamnionitis and funisitis.
|}
<noinclude>{{Bottom}}</noinclude>
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