Fetal Vascular Ectasia Can be an Artifact of Placental Fixation.

Background: Placentas from outlying hospitals are formalin-fixed en route to our laboratory. We identified that chorionic, stem villus, and umbilical vessels in these fixed placentas are ectatic with greater frequency than in our in-house fresh placentas.

Methods: We searched our LIS for third trimester placentas using keywords "ectasia" or "ectatic" over a 12-month period. We fixed incoming in-house placentas over a 2-week period for 24-72 hours and tabulated the presence or absence of vascular ectasia as defined by Parast et al, 2008.

Results: The LIS search identified 61% of placental cases from outlying hospitals that had ectatic vessels vs 3% of in-house placentas ( < .001). Of 38 placentas fixed in a 2-week period, 45% had ectatic chorionic or stem villus vessels and 21% had umbilical vessel ectasia. In comparison, in the 2 subsequent weeks, 3.8% ( < .001) of fresh placentas had vascular ectasia.

Conclusion: These data suggest that large fetal vessels in the placenta become engorged with blood at delivery and, if fixed soon after delivery, remain ectatic and congested when processed for pathology. The identification of artifactual ectasia is important because fetal vessel ectasia can suggest the presence of fetal vascular malperfusion (FVM) if diagnostic signs of FVM are present.