Sensitivity and specificity of finding of multinucleate trophoblastic giant cells in decidua in placentas from high-risk pregnancies.

This is a retrospective analysis of sensitivity and specificity of clustered placental basal plate multinucleate trophoblastic giant cells for various clinical conditions and placental lesions associated with fetal and placental hypoxia. Selected clinical and placental parameters of 375 consecutive cases of placentas with clusters of multinucleate trophoblastic giant cell (at least 3 cells with at least 3 nuclei) in the decidua (study group) were compared with all remaining 2674 placentas concurrently studied (control group) in 20-week-or-more high-risk pregnancies. Multinucleate trophoblastic giant cell was found in 12.3% of placentas. The study group had statistically significantly more cases of preeclampsia, abnormal Dopplers, induction of labor, and cesarean sections, with its placentas lighter and with more common other hypoxic lesions than in the control-group placentas. The multinucleate trophoblastic giant cell prevalence negatively correlated with gestational age (R = -0.56), peaking at the turn of the second and the third trimesters of pregnancy and declining afterward, and most strongly correlated with the excessive amount of extravillous trophoblasts in the chorionic disc (R = +0.33). The sensitivity of multinucleate trophoblastic giant cells was, on average, 3 times lower than the specificity, the latter averaging greater than 90%. In conclusion, finding of multinucleate trophoblastic giant cells is not exclusively limited to uteroplacental malperfusion of preeclampsia but is also seen in other types of high-risk pregnancy and in association with other placental hypoxic lesions and patterns. Multinucleate trophoblastic giant cells most likely reflect a premature fusion of extravillous trophoblasts because of several factors, likely including also hypoxia. Being highly specific, finding the multinucleate trophoblastic giant cells is unlikely to give a false-positive result and therefore has high value in retrospectively explaining the perinatal morbidity and mortality.