Vascular anastomoses in dichorionic diamniotic-fused placentas.

Department of Anatomic Pathology, University of Bologna, Bologna, Italy.
International Journal of Gynecological Pathology (Impact Factor: 1.63). 11/2003; 22(4):359-61. DOI: 10.1097/01.PGP.0000070848.25718.3A
Source: PubMed

ABSTRACT A case of fetal twin-to-twin cytomegalovirus infection through a dichorionic diamniotic (DiDi)-fused placenta prompted our search for possible vascular anastomoses in this type of placenta. This case and three additional DiDi-fused placentas were studied with gross (macro) sections and a three-dimensional (3D) stereomicroscopic technique. Two twins were dizygotic (they differed in gender and blood groups) and the other two were probably monozygotic. Macrosections and 3D-image analysis demonstrated side-to-side connections between small subchorionic vessels. These findings demonstrate that vascular anastomoses are present in DiDi-fused placentas.

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    • "It does not happen that way. Anastomosis of placental circulation has been found to have happened only a handful of times in examination of several thousand fused dichorionic dizygotic placentas (Foschini et al., 2003). "
    Embryogenesis, 04/2012; , ISBN: 978-953-51-0466-7
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    • " It has , however , become clear that chimeras among delivered DZ twins are far more common ( van Dijk et al . , 1996 ) than blood vessel anasto - moses between dichorionic placentas ( Robertson and Neer , 1983 ; Bjoro and Bjoro , 1985 ; Lage et al . , 1989 ; Benirschke , 1990 , 1992 , 1995 ; Machin et al . , 1995 ; Benirschke and Masliah , 2001 ; Foschini et al . , 2003 ) . There are nowhere near enough anastomoses between dichorionic placentas to account for the observed frequency of chimeras . This can reasonably be considered to refute that traditional supposition . Reports of finding chimerism only in blood arise overwhelmingly from situations in which no tissue other than blood was examined ."
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