Difference between revisions of "Twin placentas"

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Twin placentas (view source)

Revision as of 13:26, 23 January 2014

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→‎Twin-to-twin transfusion syndrome
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'''Twin placentas''' often come to the pathologist... even if they are normal.  In these specimens, usually, the chorion is the key; the pathologist may be able to sort-out whether the twins are monozygotic (identical) or dizygotic (fraternal).
'''Twin [[placenta]]s''' often come to the pathologist... even if they are normal.  In these specimens, usually, the chorion is the key; the pathologist may be able to sort-out whether the twins are monozygotic (identical) or dizygotic (fraternal).


==General==
=Monozygotic versus dizygotic twins=
If no membrane between the fetuses.
==Monoamniotic-monochorionic gestation==
*Abbreviated ''MoMo''.
===General===
*Split at approximately 7th day.
*Split at approximately 7th day.
*Monozygotic twins.
*Always monozygotic twins.
*Very rare.
*High rate of complications - cords get into knots.


===Diamnionic-monochorionic (DiMo)===
===Gross===
*No interposed chorion.<ref name=Ref_H4P2_979>{{Ref H4P2|979}}</ref>
*No membrane between the fetuses - apparently clinically.
*Always monozygotic.
*Umbilical cord attachments usually very close to one another.<ref name=Ref_Placenta133>{{Ref Placenta|133}}</ref>
*Highest risk of TTTS (twin-to-twin transfusion syndrome).


===Diamnionic-dichorionic (DiDi)===
==Diamniotic-monochorionic gestation==
*Abbreviated ''DiMo''.
===General===
*The dogma is that the twins are always monozygotic.
**There is a case report of an exception.<ref name=pmid12853583>{{Cite journal  | last1 = Redline | first1 = RW. | title = Nonidentical twins with a single placenta--disproving dogma in perinatal pathology. | journal = N Engl J Med | volume = 349 | issue = 2 | pages = 111-4 | month = Jul | year = 2003 | doi = 10.1056/NEJMp030097 | PMID = 12853583 }}</ref>
*Highest risk of TTTS ([[twin-to-twin transfusion syndrome]]).
 
===Gross===
Features - T-zone membrane is:<ref name=Ref_Placenta128>{{Ref Placenta|128}}</ref>
*Thin.
*Translucent.
*No blood vessel remnants.
 
===Microscopic===
Features:<ref>URL: [http://library.med.utah.edu/WebPath/PLACHTML/PLAC006.html http://library.med.utah.edu/WebPath/PLACHTML/PLAC006.html]. Accessed on: 30 October 2013.</ref>
*No chorion in the T-zone - '''key feature'''.
 
====Images====
<gallery>
Image:Monochorionic Diamniotic Twins, Intervening Membrane.jpg | Di-Mo placenta. (WC/euthman)
</gallery>
*[http://www.pathologypics.com/PictView.aspx?ID=1304 Diamniotic-monochorionic gestation (pathologypics.com)].
*[http://library.med.utah.edu/WebPath/PLACHTML/PLAC006.html Di-Mo placenta (utah.edu)].
 
===Sign out===
<pre>
TWIN PLACENTA, UMBILICAL CORDS AND FETAL MEMBRANES, BIRTH:
- FETAL MEMBRANES AT T-ZONE:
-- CHORION ABSENT (DIAMNIOTIC-MONOCHORIONIC GESTATION).
- TWIN A:
-- THREE VESSEL UMBILICAL CORD WITHIN NORMAL LIMITS.
-- FETAL MEMBRANES WITHIN NORMAL LIMITS.
-- PLACENTAL DISC WITH THIRD TRIMESTER VILLI WITHIN NORMAL LIMITS.
- TWIN B:
-- THREE VESSEL UMBILICAL CORD WITHIN NORMAL LIMITS.
-- FETAL MEMBRANES WITHIN NORMAL LIMITS.
-- PLACENTAL DISC WITH THIRD TRIMESTER VILLI WITHIN NORMAL LIMITS.
</pre>
 
==Diamniotic-dichorionic gestation==
*Abbreviated ''DiDi''.
===General===
*Most dizygotic (70%), may be monozygotic (30%).
*Most dizygotic (70%), may be monozygotic (30%).
*If monozygotic -- split before 3 days.
*If monozygotic -- split before 3 days.


===Gross===
Features - T-zone:<ref name=Ref_Placenta129>{{Ref Placenta|129}}</ref>
*Thick.
*Less translucent.
*Blood vessels - fine branching.
===Microscopic===
Features:
*Chorion present in the T-zone.
====Images====
<gallery>
Image:Diamniotic-dichorionic_twin_placenta_-_low_mag.jpg | DiDi placenta. (WC)
Image:Diamniotic dichorionic placenta, HE 1.jpg | DiDi placenta. (WC/euthman)
Image:Diamniotic dichorionic placenta, HE 2.jpg | DiDi placenta. (WC/euthman)
</gallery>
*[http://library.med.utah.edu/WebPath/PLACHTML/PLAC005.html DiDi placenta (utah.edu)].
===Sign out===
====Normal====
<pre>
TWIN PLACENTA, UMBILICAL CORDS AND FETAL MEMBRANES, BIRTH:
- FETAL MEMBRANES AT T-ZONE:
-- CHORION PRESENT (DIAMNIOTIC-DICHORIONIC GESTATION).
- TWIN A:
-- THREE VESSEL UMBILICAL CORD WITHIN NORMAL LIMITS.
-- FETAL MEMBRANES WITHIN NORMAL LIMITS.
-- PLACENTAL DISC WITH THIRD TRIMESTER VILLI WITHIN NORMAL LIMITS.
- TWIN B:
-- THREE VESSEL UMBILICAL CORD WITHIN NORMAL LIMITS.
-- FETAL MEMBRANES WITHIN NORMAL LIMITS.
-- PLACENTAL DISC WITH THIRD TRIMESTER VILLI WITHIN NORMAL LIMITS.
</pre>
====Early delivery====
<pre>
TWIN PLACENTA, UMBILICAL CORDS AND FETAL MEMBRANES, CESAREAN SECTION:
- FETAL MEMBRANES AT T-ZONE:
-- CHORION PRESENT (DIAMNIOTIC-DICHORIONIC GESTATION).
- TWIN A:
-- THREE VESSEL UMBILICAL CORD WITHIN NORMAL LIMITS.
-- FETAL MEMBRANES WITHIN NORMAL LIMITS.
-- PLACENTAL DISC WITH FOCALLY MILDLY LARGE THIRD TRIMESTER VILLI AND
  ZONAL CONGESTION.
- TWIN B:
-- THREE VESSEL UMBILICAL CORD WITHIN NORMAL LIMITS.
-- FETAL MEMBRANES WITHIN NORMAL LIMITS.
-- PLACENTAL DISC WITH FOCALLY MILDLY LARGE THIRD TRIMESTER VILLI.
</pre>
=Pathology seen only in twin pregnancies=
==Twin-to-twin transfusion syndrome==
==Twin-to-twin transfusion syndrome==
===General===
===General===
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Clinical:
Clinical:
*Donor:
*Donor:
**Twin: hypovolemic, oliguric, oligohydramnic, +/- anemia, +/-hypoglycemia, +/- small pale organs.
**Twin: hypovolemic, oliguric, oligohydramnic, +/- [[anemia]], +/-hypoglycemia, +/- small pale organs.
**Placental disc: large, pale.
**Placental disc: large, pale.
*Recipient:
*Recipient:
**Twin: hypervolemia, polyuria, polyhydramnios, +/- hydrops fetalis, +/- CHF, hemolytic janundice, +/- large congested organs.
**Twin: hypervolemia, polyuria, [[polyhydramnios]], +/- [[hydrops fetalis]], +/- CHF, hemolytic janundice, +/- large congested organs.
**Placental disc: small, firm, congested.
**Placental disc: small, firm, congested.


===Gross===
===Gross===
*Large vessels that connect the two umbilical cords.
*Large vessels that connect the two umbilical cords.
Image:
<gallery>
Image:De Wikkellkinderen.jpeg | Painting thought to depict TTTS. (WC)
</gallery>


===Microscopic===
===Microscopic===
Michael
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