syncytial knot


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syn·cy·tial knot

a localized aggregation of syncytiotrophoblastic nuclei in the villi of the placenta during early pregnancy.

syncytial knot

A multinucleated aggregate of syncytial nuclei at the surface of terminal villi in the placenta, which is rarely seen under 20 weeks of gestation. In term placentas, most syncytial knots are regarded as artefacts of tangential sectioning; the minority are syncytial sprouts, bridges, or apoptotic knots. They are consistently present, increasing with gestational age, and can be used to evaluate villous maturity.

Syncytial knots are associated with uteroplacental malperfusion (maternal diabetes, hypertension, pre-eclampsia and anaemia) and are an important datum in placental examination. In placentas without a history of malperfusion or clinical conditions associated with malperfusion, at 20 to 25 weeks, syncytial knots average 7%; at 26 to 33 weeks, 13%; at 36 weeks, 22.5%; at term, 37 to 40 weeks, term placentas have an average of 28% syncytial knots.

syncytial knot

Obstetrics A multinucleated protrusion from the trophoblastic surface which is commonly found in later pregnancy, excessively so in post-term gestation. See Chorionic villi. Cf Syncytial bud, Syncytial sprout.

syn·cy·tial knot

(sin-sish'ăl not)
A localized swelling or aggregation of syncytiotrophoblastic nuclei in the villi of the placenta during early pregnancy.
Synonym(s): nuclear aggregation.
References in periodicals archive ?
The slides were studied under light microscope for identification of syncytial knots, fibrinoid necrosis, stromal fibrosis, congestion and calcification per low power field 10x objective for general architecture and 40x objective for further (conformed fibrosis, calcification and congestions in the slide of abruption placenta).
Whereas mean and standard deviation were calculated for numerical (continuous) variables which included fibrinoid necrosis, calcification, and syncytial knots, and weight and apgar score of fetus were calculated by Student ttest.
Microscopic study was done to evaluate placental infarcts and syncytial knots.
Syncytial knots were found in all placentas but they were considerably more at decreasing levels of maternal hemoglobin (19.79 5.22).
This study demonstrated high frequencies of decidual arteriopathy, accelerated villous maturation, syncytial knots, cytotrophoblastic proliferation, stromal fibrosis, and stromal oedema in the preeclamptic/eclamptic group compared with the control group.
Histological findings Mild PE, n Severe PE, n (%) (%) Stromal oedema 5 (35.7) 24 (61.5) Stromal fibrosis 7 (50.0) 19 (48.7) Syncytial knots 7 (50.0) 17 (43.6) Cytotrophoblastic proliferation 6 (42.9) 28 (71.8) Accelerated villous maturation 8 (57.1) 27 (69.2) Decidual arteriopathy 9 (64.3) 30 (76.9) Histological findings Eclampsia, n Control, n (%) (%) Stromal oedema 2 (25.0) 55 (45.1) Stromal fibrosis 3 (37.5) 38 (31.1) Syncytial knots 5 (62.5) 35 (28.7) Cytotrophoblastic proliferation 6 (75.0) 31 (25.4) Accelerated villous maturation 6 (75.0) 38 (31.1) Decidual arteriopathy 7 (87.5) 43 (35.2) Histological findings p value of mild PE, severe PE, and eclampsia, resp.
Because of villous enlargement, the placenta looks hypomature, except for the focally increased syncytial knots, which is not, however, a constant feature.
(63) The PU features homogeneous placental hypermaturity and hypovascularity, with slender, pencillike chorionic villi; so-called terminal villous hypoplasia (13); increased extracellular matrix of chorionic villi and apoptotic syncytial knots; and decreased villous Hofbauer cells and villous cytotrophoblasts.
Histological examination revealed that the incidences of villi with syncytial knots and that of cytotrophoblastic cells were significantly greater at high altitude compared to low altitude.
Syncytial knots are seen with increased frequency in the last weeks of pregnancy and more villi show these changes in high risk pregnancies.
Syncytial knots: Absent in 68% of cases and minimal in 32% of cases.
In light microscopic examination of the placental villi were screened for counting of number of syncytial knots per 100 villi, fibrinoid necrosis, stromal fibrosis, medial coat proliferation of foetal blood vessels, intervillous haemorrhage, cytotrophoblastic cellular proliferation and calcification.