Placenta
Author:
Mikael Häggström [note 1]
Contents
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:
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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
- ↑ 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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References
Image sources