Latest revision as of 13:26, 23 January 2014

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).

Monozygotic versus dizygotic twins

Monoamniotic-monochorionic gestation

Abbreviated MoMo.

General

Split at approximately 7th day.
Always monozygotic twins.
Very rare.
High rate of complications - cords get into knots.

Gross

No membrane between the fetuses - apparently clinically.
Umbilical cord attachments usually very close to one another.^[1]

Diamniotic-monochorionic gestation

Abbreviated DiMo.

General

The dogma is that the twins are always monozygotic.
- There is a case report of an exception.^[2]
Highest risk of TTTS (twin-to-twin transfusion syndrome).

Gross

Features - T-zone membrane is:^[3]

Thin.
Translucent.
No blood vessel remnants.

Microscopic

Features:^[4]

No chorion in the T-zone - key feature.

Images

Di-Mo placenta. (WC/euthman)

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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.

Diamniotic-dichorionic gestation

Abbreviated DiDi.

General

Most dizygotic (70%), may be monozygotic (30%).
If monozygotic -- split before 3 days.

Gross

Features - T-zone:^[5]

Thick.
Less translucent.
Blood vessels - fine branching.

Microscopic

Features:

Chorion present in the T-zone.

Images

DiDi placenta. (WC)
DiDi placenta. (WC/euthman)
DiDi placenta. (WC/euthman)

DiDi placenta (utah.edu).

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Normal

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.

Early delivery

 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.

Pathology seen only in twin pregnancies

Twin-to-twin transfusion syndrome

General

Abbreviated as TTTS.

Definition:

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.
- Only seen in monozygotic twins.
- Vascular connection may be vein-to-vein, artery-to-vein, artery-to-artery (uncommon).^[6]

Prevalence:

Seen in ~15% of monozygotic twins.^[6]

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

Large vessels that connect the two umbilical cords.

Image:

Painting thought to depict TTTS. (WC)

Microscopic

Features:^[7]

Artery-to-vein anatomosis - where artery and vein are associated with different umbilical cords.
Donor twin side of placenta:
- Edematous villi.
- Increased nucleated RBCs.
Recipient twin side of placenta:
- Congested.

References

↑ Baergen, Rebecca N. (2011). Manual of Pathology of the Human Placenta (2nd ed.). Springer. pp. 133. ISBN 978-1441974938.
↑ Redline, RW. (Jul 2003). "Nonidentical twins with a single placenta--disproving dogma in perinatal pathology.". N Engl J Med 349 (2): 111-4. doi:10.1056/NEJMp030097. PMID 12853583.
↑ Baergen, Rebecca N. (2011). Manual of Pathology of the Human Placenta (2nd ed.). Springer. pp. 128. ISBN 978-1441974938.
↑ URL: http://library.med.utah.edu/WebPath/PLACHTML/PLAC006.html. Accessed on: 30 October 2013.
↑ Baergen, Rebecca N. (2011). Manual of Pathology of the Human Placenta (2nd ed.). Springer. pp. 129. ISBN 978-1441974938.
↑ ^6.0 ^6.1 Humphrey, Peter A; Dehner, Louis P; Pfeifer, John D (2008). The Washington Manual of Surgical Pathology (1st ed.). Lippincott Williams & Wilkins. pp. 469. ISBN 978-0781765275.
↑ Humphrey, Peter A; Dehner, Louis P; Pfeifer, John D (2008). The Washington Manual of Surgical Pathology (1st ed.). Lippincott Williams & Wilkins. pp. 469-70. ISBN 978-0781765275.

[Ref_Placenta133-1] Baergen, Rebecca N. (2011). Manual of Pathology of the Human Placenta (2nd ed.). Springer. pp. 133. ISBN 978-1441974938.

[pmid12853583-2] Redline, RW. (Jul 2003). "Nonidentical twins with a single placenta--disproving dogma in perinatal pathology.". N Engl J Med 349 (2): 111-4. doi:10.1056/NEJMp030097. PMID 12853583.

[Ref_Placenta128-3] Baergen, Rebecca N. (2011). Manual of Pathology of the Human Placenta (2nd ed.). Springer. pp. 128. ISBN 978-1441974938.

[4] URL: http://library.med.utah.edu/WebPath/PLACHTML/PLAC006.html. Accessed on: 30 October 2013.

[Ref_Placenta129-5] Baergen, Rebecca N. (2011). Manual of Pathology of the Human Placenta (2nd ed.). Springer. pp. 129. ISBN 978-1441974938.

[Ref_WMSP469-6] 6.0 ^6.1 Humphrey, Peter A; Dehner, Louis P; Pfeifer, John D (2008). The Washington Manual of Surgical Pathology (1st ed.). Lippincott Williams & Wilkins. pp. 469. ISBN 978-0781765275.

[Ref_WMSP469-70-7] Humphrey, Peter A; Dehner, Louis P; Pfeifer, John D (2008). The Washington Manual of Surgical Pathology (1st ed.). Lippincott Williams & Wilkins. pp. 469-70. ISBN 978-0781765275.

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[2]

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@@ Line 1: / Line 1: @@
 '''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).
-==Monozygotic vs. dizygotic==
+=Monozygotic versus dizygotic twins=
-If no membrane between the fetuses.
+==Monoamniotic-monochorionic gestation==
+*Abbreviated ''MoMo''.
+===General===
 *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%).
 *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==
 ===General===
@@ Line 32: / Line 127: @@
 **Placental disc: large, pale.
 *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.
 ===Gross===
 *Large vessels that connect the two umbilical cords.
+Image:
+<gallery>
+Image:De Wikkellkinderen.jpeg | Painting thought to depict TTTS. (WC)
+</gallery>
 ===Microscopic===

Difference between revisions of "Twin placentas"

Latest revision as of 13:26, 23 January 2014

Contents

Monozygotic versus dizygotic twins

Monoamniotic-monochorionic gestation

General

Gross

Diamniotic-monochorionic gestation

General

Gross

Microscopic

Images

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Diamniotic-dichorionic gestation

General

Gross

Microscopic

Images

Sign out

Normal

Early delivery

Pathology seen only in twin pregnancies

Twin-to-twin transfusion syndrome

General

Gross

Microscopic

See also

References

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