Placenta

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Revision as of 17:19, 17 August 2020 by Mikael Häggström (talk | contribs) (+Comprehensiveness)
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Author: Mikael Häggström [note 1]

Comprehensiveness

Comprehensiveness

On this resource, the following formatting is used for comprehensiveness:

  • Minimal depth
  • (Moderate depth)
  • ((Comprehensive))

Gross processing

  • Determine the shape of the placenta
  • Look for any accessory lobes
  • Determine the completeness of placental membranes, opacity, color and consistency (slimy/slippery?)
  • Determine the point of rupture from nearest margin
  • Note where the membranes are inserted
  • Examine the umbilical cord
  • Measure the distance between the insertion point and the nearest placental margin
  • Measure the cord length and give proximal and distal diameter
  • Count the number of vessels away from the insertion
  • Weigh the trimmed disk, after having trimmed away the cord and membranes, and after having removed excess amounts of loose retroplacental blood clots over the maternal surface.
  • Examine the fetal surface (chorionic plate):
  • Note its color
  • Look for any pathologies including granular excrescences, subchorionic fibrin or subamniotic hemorrhage
  • Look at the integrity and extent of the vasculature, including any thrombosis and traumatic damage
  • Examine the maternal surface (basal plate) for completeness, adherent blood clots, depressions, calcifications and fibrin
  • Take membrane rolls and cord sections, before sectioning the placenta
  • With the fetal surface down on the cutting board, cut the placenta at 1cm intervals so that it can be reconstructed
  • Palpate the parencyhmal sections for areas of induration.
  • Note the color of the parenchyma and describe any pale areas, cysts, infarcts (estimate total amount of infarcted tissue), thrombi, increased fibrin and calcifications

Tissue selection

  • Distal (toward fetus) membrane roll and cross section of distal cord. It should include the area of rupture.
  • Proximal (toward placenta) membrane roll and cross section of proximal cord ( 2-3 cm from insertion). They should include membranes up to the chorionic plate.

A membrane roll is created by cutting a strip, about 3 cm wide, of membrane, from the rupture site to the placental insertion. Hold the edge with forceps and roll it around the forceps, and then cut a transverse section of the roll.
Cord sections should be no thicker than 4mm.

  • Placental section including fetal surface ( full thickness if possible)
  • Placental section including maternal surface (full thickness if possible)
  • Any lesions or abnormalities

Avoid taking placental sections near the margin

Gross report

Example:

Labeled -with patient's name and medical record number. The specimen is received fresh and consists of a placenta with attached membranes and umbilical cord. The trimmed placental weight is __ grams. The membranes are pink and translucent with a marginal insertion. The site of rupture is __ cm from the nearest placental margin. There is no accessory lobe. The placental disc measures __ cm and varies in thickness from __ to __ cm. The umbilical cord is tan-white and marginally inserted, __ cm from the nearest placental margin, and measures __ cm in length, __ cm in proximal diameter and __ cm in distal diameter. Cut sections of the cord reveal three blood vessels. The fetal surface is __. The maternal surface is __. Sectioning reveals a __. Representative sections are submitted for microscopic examination in four cassettes.

KEY OF SECTIONS:

  • 1- distal membranes and umbilical cord
  • 2- proximal membranes and umbilical cord
  • 3- placental section including fetal surface
  • 4- placental section including maternal surface
This example is Public Domain, and can be copied without any need for author attribution.

Microscopy report

Example:

Third trimester placenta with term villous histology. Placental weight (__ gm), at __th percentile for gestational age. A focal organizing mural thrombus of a stem villous blood vessel. Tiny intervillous thrombus in a random placental section. A chorionic cyst (1.3 cm) in the subchorionic zone. Membranes without significant histopathologic changes. Trivascular umbilical cord with marginal insertion, with no significant histopathologic changes.

Notes

  1. For a full list of contributors, see article history. Creators of images are attributed at the image description pages, seen by clicking on the images. See Patholines:Authorship for details.

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