Chorangiosis of Chorionic Villi: What Does It Really Mean?

Abstract

Chorangiosis has been regarded as a result of low-grade placental hypoxia associated with pregnancy risk factors and abnormal outcomes. It is unknown whether these are a consequence of chorangiosis itself or of associated other placental pathology.Context.— To prove that chorangiosis itself does not portend an increased risk for pregnancy unless associated with other placental pathology.Objective.— This retrospective statistical study analyzes 1231 consecutive placentas with diffuse or focal hypervascularity of chorionic villi: 328 with preuterine pattern of chronic hypoxic placental injury (group 1), 297 with uterine type of chronic hypoxic placental injury (group 2), and 606 cases with chorangiosis (group 3) not fulfilling the inclusion criteria for groups 1 or 2.Design.— Group 2, with 33 cases of chorangiosis (11.1%), featured 10 and 11 statistically significant highest percentages of abnormal clinical and placental variables, respectively; group 3 featured the highest percentages of multiple pregnancy, the heaviest placentas, and the most common acute chorioamnionitis, fetal inflammatory response; and group 1 had the highest proportion of mild erythroblastosis of fetal blood. When comparing groups 1 and 3, 21 of 29 clinical risk factors/outcomes (72.4%) and 30 of 41 placental variables (73.2%) were more common in group 1.Results.— Presence of diffuse hypoxic patterns of placental injury adds prognostically negative significance to increased vascularity of chorionic villi. Chorangiosis without those patterns portends minimal risk for the pregnancy, and is associated with significantly fewer pregnancy risk factors, abnormal outcomes, and other placental abnormalities.Conclusions.—

Histological Analysis of Term Placentas from Hyperimmune Globulin-Treated and Untreated Mothers with Primary Cytomegalovirus Infection

“…Chorangiosis is defined as extreme villous hypervascularity and has been regarded as a placental adaptive response to long-standing hyp­oxia (Fig. 2) [18]. The term was introduced by Altshuler [24] 34 years ago and defined as at least 10 vascular profiles per terminal/intermediate chorionic villous in 10 chorionic villi per ×10 objective microscopic field in at least 10 areas of three or more random cotyledons.…”

“…Similarly, Maidji et al [9] reported an increased villous microvascular density in the three treated placentas studied, suggesting a compensatory effect of HIG. However, it should be taken into account that chorangiosis has also been found in placentas with physiological hypoxia from high altitudes, in placentas from women who smoked during gestation, and in several other conditions such as maternal diabetes mellitus, maternal anemia, and air pollution [18]. Therefore, chorangiosis is a mechanism of compensation that can be induced by many different conditions.…”

Histopathological Study of Villous Hypervascularity and Chorangiosis at Different Maternal Hemoglobin Levels

“…The effects of hypoxia on vascularity of villi have been evaluated in Ohio and it was observed that presence of diffuse patterns of hypoxic placental injury adds negative significance to increased vascularity of the chorionic villi. 5 Increased capillaries per chorionic villous in maternal anemia is also confirmed by Soni RB in 2013. 13 Placental chorangiosis was studied by De La Ossa et al and it was found that hypoxic stimulus may lead to an extreme villous capillary proliferative activity, maybe via growth factors such as vascular endothelial growth factor.…”

“…Presence of diffuse patterns of hypoxic placental injury imparts prognostically undesirable significance to increased vascularity of the chorionic villi. 5 Chorangiosis is linked with adverse perinatal outcomes, however the definitive mechanism is still unknown but the interaction of fetal, placental and maternal factors may well combine to produce such pathologic change. Whatever the cause, chorangiosis can be considered as a sign of possible clinical significance.…”

Clinicopathologic Correlations in Histopathologic Report of Placenta: Can We Do Something More?

“…4 Its significance is still not completely clear, but it is traditionally related to intrauterine hypoxia/underperfusion, diabetes, and many other conditions. As Stanek 4 recently stated, chorangiosis/ villous hypervascularity per se is not related to poor pregnancy outcome, but it can be considered as the epiphenomenon of intrauterine placental hypoxia. On some occasions, chorangiosis/hypervascularity is the very first readily observed lesion, and it may arouse suspicions about possible hypoxia, leading us to look for other, sometimes very subtle lesions.…”