Placental hypoxic overlap lesions: A clinicoplacental correlation

Abstract

Placental hypoxic overlap lesions are associated with clinical complications of pregnancy and predispose to thrombotic lesions, some most likely stasis-induced.

Chorangiosis of Chorionic Villi: What Does It Really Mean?

“…5,33,34 As compared with group 2, groups 1 and 3 featured not only lower prevalence of clinical risk factors for in utero hypoxia, 35 but also lower prevalence of other placental abnormalities, particularly the complex of lesions associated with chronic poor uteroplacental perfusion (decidual arteriolopathy, excessive amount of extravillous trophoblasts, chorionic disc microscopic pseudocysts, maternal floor multinucleate trophoblasts), acute placental hypoxic lesions (infarction of chorionic villi; laminar necrosis of membranes, ie, acute-on-chronic hypoxic overlap lesions), and some features of fetal thrombotic vasculopathy (fetal vascular thrombi; dilatation of fetal veins; lobular villous hemosiderosis, ie, thrombotic-over-hypoxic overlap lesions). 30 The results also indicate that as in group 1, when in addition to hypervascularity other histologic features of diffuse preuterine placental hypoxia were present (delayed maturation, decreased extracellular matrix of chorionic villi, increased Hofbauer cells, increased villous cytotrophoblasts), the frequency of clinical risk factors and abnormal outcomes is higher than that in pure chorangiosis (group 3), that is, placentas without the additional histologic findings mentioned in Figure 2 in which chorangiosis was most commonly focal. Our results confirmed our previous findings of increased prevalence of chorangiosis in multiple pregnancies 16 but not in stillbirths.…”

“…32 The author regards this opinion as a moot point because even if villous capillaries are frequently congested in villous hypervascularity (Figure 1), their numbers of lumens are indeed increased as a result of branching angiogenesis. Of course, chorangiosis does not exclude poor placental perfusion leading to hypoxic overlap lesions 30 due to decidual arteriolopathy and hypoxic extravillous trophoblastic lesions in rare cases in group 1 or 3 (Table). This can modify the histologic pattern, producing variability in placental maturation (Figure 1, B and E).…”

“…30 The significance of this ''complicated'' versus ''pure'' chorangiosis is also unclear and has not been addressed so far. It is unknown whether abnormal pregnancy outcomes are indeed a consequence of chorangiosis itself or if chorangiosis is an adaptive and possibly protective mechanism against in utero hypoxia.…”

Hypoxia: From Placental Development to Fetal Programming

“…Hypoxia induced changes of the human placenta reflect a compensatory mechanism to guarantee fetal adequate nourishment; however, in most of the cases, these adaptive changes are not sufficient. Two major findings are key features to detect hypoxic insults: villous maturity and increased vascularization (Stanek, , ).…”

“…Stanek (, , ) investigated the correlation between placental histological characteristics of the three hypoxic injuries (preplacental, utero placental, and postplacental) with the clinicopathological findings. Briefly, preplacental hypoxic insults induce diffuse changes.…”