Table 3.
Pathologic features.
| Case | GA | Placental weight (g) | Weight percentile [32] | Gross pathology | H&E microscopic pathology | H&E microscopic category/grade (see Table 2) | ACE2 IHC | TMPRSS2 IHC | nCapsid IHC | SARS-CoV-2 RNA ISH |
|---|---|---|---|---|---|---|---|---|---|---|
| MGH2 | 30 | 473 combined | ~25th | DDTP, circumvallation both twins | Both twins with acute chorioamnionitis (maternal stage 1, grade 1) Twin B with focal AVV (FVM, LG) |
FVM/LG Infe/LG Gross |
ST—circumferential EVT CT Scattered decidua parietalis cells |
Negative | Negative | Negative |
| MGH3 | 33 + 4 | 336 | ~10th | Marginal insertion of the umbilical cord | Subchorionic thrombus | Other/LG Gross |
ST—primarily biased CT EVT Scattered decidua parietalis cells |
Negative | Negative | Negative |
| MGH4 | 40 + 1 | 403 | <10th | None | Meconium pigment Acute chorioamnionitis (maternal stage 2, grade 1) with fetal inflammatory response (fetal stage 1, grade 1) Membrane myometrial fibers |
Infe/LG Hypo/LG Other/LG |
ST—biased CT EVT Scattered decidual parietalis cells |
Focal in muscularized stem villous vessels walls | Negative | Rare ST and CT |
| MGH8 | 37 + 4 | 428 | ~25th | Green discolored, 1 cm central firm parenchymal mass | Meconium pigment Decidual arteriopathy with acute atherosis Single small central placental infarct, usual type Patchy increased perivillous fibrin |
MVM/HG Hypo/LG |
ST—primarily biased, some circumferential CT EVT Scattered decidua parietalis cells |
Weak in villous endothelium | Negative | Negative |
| MGH9 | 36 | 469 | ~45th | Hypercoiled umbilical cord, central parenchymal mass not measured | Single central placental infarct, usual type with peripheral increased perivillous fibrin, Hofbauer cell hyperplasia, focal |
MVM/LG Infl/LG Gross |
ST—circumferential CT EVT Maternal endothelium Scattered decidua parietalis cells |
Spotty weak villous endothelium | Multiple foci of strong staining in ST | Multiple foci of strong staining in ST |
| MGH10 | 22 | 54 | <10th | None | Postmortem AVV, VSK, SVO Chorangiomatosis Necrotizing acute chorionitis Plasma cell deciduitis |
FVM/HG- postmortem Infe/LG Infl/LG Other/HG |
ST—stromal biased CT EVT |
Negative | Negative | Negative |
| MGH11 | 30 + 6 | 524 | ~30th | Fused DDTP, velamentous cord insertion twin A | Patchy chorangiosis | Hypo/LG Gross |
ST—stromal biased EVT Decidual parietalis stromal cells and maternal endothelium |
Negative | ||
| MGH12 | 38 + 5 | 522 | ~60th | Green discolored membranes, Rightward coiled umbilical cord | IMFD Meconium pigment VUE, ungradeable Intervillositis |
FVM/LG Infl/LG Hypo/LG Gross |
ST—stromal biased CT EVT |
Negative | ||
| MGH13 | 36 | 487 | ~65th | None | Meconium pigment IMFD Subchorionic thrombus Decidual arteriopathy, hypertrophic type Adherent basal plate myometrial fibers |
FVM/LG MVM/LG Other/HG |
ST—stromal biased EVT Decidual parietalis stromal cells and maternal endothelium |
Negative | ||
| MGH14 | 41 + 1 | 353 | <10th | 5 firm parenchymal regions up to 1.6 cm in size | Multifocal regions of increased perivillous fibrin | MVM/HG | ST—stromal biased CT EVT |
Negative | ||
| BWH2 | 39 + 5 | 518 | ~50th | Marginal insertion of the umbilical cord | Acute chorioamnionitis with fetal (maternal stage 1, grade 1) with fetal inflammatory response (fetal stage 1, grade 1) | Infe/LG Gross |
ST—circumferential with some stromal biased CT EVT Maternal endothelium Decidua Scattered decidua parietalis cells |
Negative | Negative | Negative |
| BWH4 | 37 | 595 | >90th | Marginal insertion of the umbilical cord | Acute chorioamnionitis (maternal stage 1, grade 1) Meconium pigment Fetal normoblastemia Adherent myometrial fibers |
Infe/LG Hypo/HG Other/LG Gross |
ST—stromal biased CT EVT Maternal endothelium Decidua |
Negative | Negative | Focal positive maternal endothelial cells in decidua parietalis Placenta-negative |
| BWH5 | 37 + 1 | 797 | >90th | True knot of the umbilical cord | Acute chorioamnionitis (maternal stage 1, grade 2) with fetal inflammatory response (fetal stage 2–3, grade 2) Intervillous thrombus with associated placental infarct |
Infe/HG Other/LG Gross |
ST—stromal biased CT EVT Maternal endothelium Rare umbilical artery endothelial cells Decidua |
Weak focal villous endothelial cells and stem vessel smooth muscle | Negative | Negative |
| BWH6 | 38 + 3 | 477 | ~45th | Rightward coiled umbilical cord | Decidual arteriopathy | MVM/LG Gross |
ST—mix of circumferential and stromal biased CT EVT Scattered decidua parietalis cells |
Negative | Negative | Negative |
| BWH9 | 38 + 3 | 330 | <10th | Velamentous insertion of the umbilical cord | None | Gross | ST—circumferential CT EVT Decidua |
Weak in villous endothelium | Negative | Negative |
| BIDMC1 | 37 + 2 | 526 | ~75 | None | None | None | ST—stromal biased EVT Decidua |
Weak in villous endothelium, negative in membranes and umbilical cord | Negative | Negative in placental tissues |
| BIDMC2 | 35 + 3 | 454 | ~60 | None | None | None | ST—stromal biased EVT Decidua |
Weak in villous endothelium, Umbilical cord endothelium and very weak and patchy in the ST | Negative | Negative in placental tissues |
| BIDMC3 | 31 + 6 | 290 | ~10th | None | Villous edema Subchorionic thrombus |
Hypo/LG Other/LG |
ST—stromal biased EVT Decidua |
Very weak in villous endothelium, negative in membranes and umbilical cord | Negative | Negative in placental tissues |
| BIDMC4 | 29 + 3 | 363 | >90th | None | Acute chorioamnionitis (maternal stage 1, grade 1) with fetal inflammatory response (fetal stage 1, grade 1) Villous edema |
Infe/LG Hypo/LG |
ST—stromal biased, rare circumferential EVT Squamous metaplasia of amnion on umbilical cord |
Weak in villous endothelium, negative in membranes and umbilical cord | Negative | Negative |
| BIDMC5 | 35 + 5 | 518 | ~80th | Marginal insertion of the umbilical cord | None | Gross | ST—stromal biased EVT Decidua |
Weak in villous endothelium, negative in membranes and umbilical cord | Weak and focal in ST | Negative in placental tissues |
AVV avascular villi, CT cytotrophoblast, DDTP diamniotic dichorionic twin placenta, EVT extravillous trophoblast, HG high grade, IHC immunohistochemistry, ISH in situ hybridization, LG low grade, ST syncytiotrophoblast, SVO stem vessel obliteration, VSK villous stromal-vascular karyorrhexis, VUE villitis of unknown etiology.