placenta




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  • Normal

    • membrane
      • amnion
      • artificial space
      • chorion
      • decidua
    • cord
      • 2 arteries
      • 1 vein
      • +/- vestigial remnants
      • stroma
      • extra vessels may just be single convoluted vessel
    • parenchyma
      • villi
        • trophoblast
        • mesenchyme
        • fetal vessels
      • lacuna
        • maternal blood
        • fibrin
      • fetal surface
        • has big umbilical vessels
      • maternal surface
        • not seen unless accreta

  • Ddx by clinical

    • twins
      • __chorionic / __amnionic
      • dichorionic = 2 placentas
      • diamnionic = there's a dividing amnionic membrane on placenta
      • combinations
        • di/di: 2 placentas
        • mono/di: has dividing membrane
        • mono/mono
        • conjoined twins
    • abruption
      • retroplacental hematoma
        • located centrally, causing depression
    • diabetes
    • gastroschisis
      • amnion vacuoles
    • IUGR
      • decidual vasculopathy
      • chronic abruption
      • large chorangioma
      • fetal thrombotic vasculopathy
      • infarcts
      • intervillositis
    • oligohydramnios
    • preeclampsia
    • preterm labor
    • PROM

  • Ddx by location

    • Membrane
    • Cord
      • funisitis
      • number of vessels
      • remnants
        • allantoic remnant
        • omphalomesenteric remnant
      • other
        • meconium induced necrosis
        • warton jelly ulcer
        • vascular
          • thrombus
          • hematoma
          • hemangioma
          • aneurysm
          • discordant arteries
        • mechanical
          • knots
          • strictures
          • torsion
          • velamentous insertion
    • parenchyma
      • GTDs
      • villitis
        • TORCH
          • toxoplasma
          • other
            • syphilis
            • varicella
            • parvovirus
          • rubella
          • CMV
          • herpes
        • listeria
        • candida
        • other
          • listeria
          • candida
          • HIV
      • intervillositis
        • chronic histiocytic intervillositis
      • vascular
        • chorangiosis
        • chorangiomatosis
        • TTTS
        • infarct
          • maternal floor infarct
            • early = collpased intervillous space, perivillous fibrin
            • late = ghost outlines
            • massive perivillous fibrin deposition mimicks infarct
        • obstruction
          • fibrotic avascular villi
          • stem vessel thrombus
          • intimal fibrin cushion
        • hematoma
          • stromal hemorrhage
            • laminated fibrin and blood
          • locations
            • retroplacental
            • marginal
            • intraplacental
            • subchorial
            • subamnionic
        • vasculitis
        • mesenchymal dysplasia
          • large stem villi
          • abundant cystic stroma
          • focally degenerate thick muscular vessels
      • maturity
      • rares: hepatic adenoma, metastasis (breast, melanoma)

  • Ddx by stains

    • cytokeratin and HSD3B1
      • positive in all GTDs
    • p63
      • positive in ETT, PSN
      • negative in EPS, PSTT
    • hPL
      • strongly positive in EPS, PSTT
      • +/- in ETT, PSN
    • hCG
      • positive in choriocarcinoma syncytial trophoblasts
    • cyclin E
      • positive in ETT
      • negative in PSN
    • Ki67
      • positive in PSTT (> 10%), ETT (> 12%)
      • weak in EPS (< 1%), PSN (< 8%)

  • Sign out

    • placenta
      • term/preterm (__weeks) singleton/twin placenta, ___ g (__ percentile)
      • __ vessel cord, mature chorionic villi
      • no chorioamnionitis, decidual vasculopathy, funisitis, or villitis
    • products of conception
      • Immature/mature chorionic villi with degenerative changes and acute inflammation consistent with retained products of conception
    • abortus
      • Immature chorionic villi consistent with early second trimester gestation
      • Acute chorionitis
      • Three vessel umbilical cord with no funisitis identified
      • Bacterial colonies in the membranes and umbilical cord (may be a secondary phenomenon occurring after fetal demise)
    • retained products
      • Necrotic, hemorrhagic and acutely inflamed decidua consistent with acute endometritis
      • No retained chorionic villi identified
      • Immature/mature chorionic villi with degenerative changes and acute inflammation consistent with retained products of conception
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