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 |
