PMC9845932_01
Ultrasound assessment of the umbilical cord in a 29-year-old mother at 37 WA, before stillbirth. (A) Ultrasound showed a bilocular cyst measuring 72 mm of major axis, and 31-52 mm of minor axis. (B) Umbilical vessel assessment of blood flow using tridimensional high definition Doppler ultrasound showing blood flow around the umbilical cord cyst.
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F1
Third-trimester ultrasound performed at 37 WA revealed a 73 mm (major axis) cystic heterogenous mass at the umbilical cord insertion (Figure 1).
Gross examination of the placenta of a 29-year-old with stillbirth at 38 WA. (A) Placental examination of the fetal plate revealed a false knot on the umbilical cord (arrow) associated with a large aneurysmal cyst at the insertion of the umbilical cord (arrowhead). (B) At dissection, the aneurysmal cyst was filled with large blood clots (arrowhead). (C) At cut-section, the placental parenchyma showed subchorionic whitish nodules and confirmed the presence of the aneurysm, in relation to the umbilical arteries (arrowhead).
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F2
At the fetal plate, a large bilocular cystic lesion was observed at the insertion of the umbilical cord (Figure 2) measuring ~8 cm of diameter. At dissection, the cystic lesion was filled up with hemorrhagic debris and large blood clots (Figure 2). Placental cut section revealed whitish subchorionic nodules compatible with subchorionic thromboses (SCT; Figure 2).
Histopathological analysis of the aneurysmal cyst of the umbilical cord in a 29-year-old mother with stillbirth at 38 WA. (A) (Hematoxylin Eosin Saffron:HES, x 100): histopathology showed a thick-walled large cyst (asterisk). (B) (HES, x 200)-(C) (Trichrome Blue, x 200): The wall of the cyst is mainly composed of mesenchymal cells and few scattered smooth muscle cells (arrows). (D) (CD34, x 200): Immunodetection of CD34 revealed few endothelial cells at the surface of the cyst (arrow). (E) (D2-40, x 200): Few mesenchymal cells exhibited cytoplasmic positivity after immunodetection (arrow). (F) (CD31, x 200): immunodetection of CD31 revealed few endothelial cells at the surface of the cyst (arrow). (G) (HES, x 200): calcified hemorrhagic debris (arrow) were seen after dissection and sampling of the aneurysmal cyst.
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F3
Histopathological analysis of the cystic lesion revealed a large cavity filled with hemorrhagic debris at the base of the umbilical cord (Figure 3). The wall of the cyst was mainly composed of elastic fibers intermingled with scattered smooth muscle cells (Figure 3). Few scattered CD34+ CD31+ D2-40+ endothelial cells were observed close to the lumen of the cyst (Figure 3).
Histopathological analysis of the placenta in a 29-year-old mother with stillbirth at 38 WA. (A) (HES, x 200): Increased perivillous fibrin (arrow) and distal villous hypoplasia (arrowhead) were seen, indicating maternal vascular malperfusion. (B) (HES, x 200): Subchorionic thrombosis was observed (arrow), characterized by linear deposition of fibrin and red blood cells in the intervillous space adjacent to the fetal plate. (C) (HES, x 400): Histopathology showed evidence of stage 1 grade 2 chorioamnionitis, characterized by neutrophilic infiltration of the decidua parietalis of the membranes (arrows), without amniotic necrosis. (D) (HES, x 200): Histopathology showed rarefaction of smooth muscle cells (arrow) at the level of umbilical vessels adjacent to the aneurysmal cyst, inserted at the fetal plate.
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F4
Histopathological analysis of the subchorionic nodules confirmed SCT (Figure 4). Concerning the placental villi, MVM and focal IPF were also observed (Figure 4). Histopathological analysis of the membranes revealed stage 1 grade 2 chorioamnionitis (Figure 4). Furthermore, histopathological analysis showed rarefaction of smooth muscle cells at the level of umbilical vessels adjacent to the aneurysmal cyst (Figure 4).