Monday, June 29, 2009


Surface Chorionic Vasculitis

Today I had a case of what appears to be insudation of protein or possibly mural fibrin in the superficial chorionic vessels with acute inflammation. The lesion has some resemblance to acute atherosis or TTP. This placenta is from a 25 week, 825 g birth weight infant with purulent chorioamnionitis, but not very intense three vessel funisitis or chorionic vasculitis, at least in terms of neutrophil density. The membranes show a marked thickening of the amnion connective tissue with neutrophils and neutrophil debris.
This vessel lesion is very distinctive, although it probably falls under the SPP category of fetal inflammatory response with thrombus. There must be specific factors causing this pattern of vascular injury. The localization suggests a direct effect either from surrounding inflammatory cells, or even amniotic fluid components. Serum factors may be detectable in umbilical vein blood. Serum factors injuring this vessel (one of several seen in this placenta) might be capable of causing similar vascular injury in the fetus, especially if the umbilical venous blood adjacent to the lesion is going directly to the fetal brain via the foramen ovale. Dr. Redline and colleagues were able to demonstrate an association of chorionic non-occlusive thrombi with cerebral palsy and other neurologic impairment1. I could not tell from this article, since it was retrospective based on neurologic impairment, the predictive value of thrombi in the chorionic vessels for neurologic impairment. I am willing to bet it is high.
The Society for Pediatric Pathology created provisional guidelines for staging and grading chorioamnionitis2. Dr. Redline led the group based on his experience and publications investigating chorioamnionitis in very low birth weight infants. These guidelines were meant to be validated through further research. The problems with obtaining research and HIPPA protocols for follow-up are daunting, and I know I shall not pursue this case. However, these advanced inflammatory placental lesions are still an area in need of better clinical pathological correlation.


1. Redline RW, Wilson-Costello D, Borawski E, Fanaroff AA, Hack M. Placental lesions associated with neurologic impairment and cerebral palsy in very low-birth-weight infants. Arch Pathol Lab Med 1998;122(12):1091-8.
2. Redline RW, Faye-Petersen O, Heller D, Qureshi F, Savell V, Vogler C. Amniotic Infection Syndrome: Nosology and Reproducibility of Placental Reaction Patterns. Pediatr Dev Pathol 2003.

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