Neuromuscular

Subperineurial Edema

Differential diagnosis
Histochemistry
Plastic sections
Vessels, Endoneurial
Ultrastructure

Subperineurial edema: Diferential Diagnosis

SUBPERINEURIAL EDEMA ± INFLAMMATION


H&E stain

Gomori trichrome stain

Subperineurial edema (Narrow arrow)
In neighboring fascicle
Inflammation
Near a small epineurial vessel (Wide arrow)


Subperineurial edema (Arrows)
Variable severity in different fascicles
Clear space between the perineurium and endoneurial contents (arrows).


H&E stain

H&E stain
Clear space contains hyaline material and occasional vessels and cells.


Toluidine blue stain

Toluidine blue stain
Subperineurial space contains hyaline material, vessels and cells.
There may be a variable degree of axon loss within fascicles.

Toluidine blue stain

Toluidine blue stain

Subperineurial Edema (Arrow): Contents

Alcian blue stain

Alcian blue stain
Subperineurial Edema: Contents
  Background: Irregular & punctate clusters of mucopolysacharides (Alcian blue positive)
  Cells: Large nuclei; Some have Alcian blue positive cytoplasm

Alcian blue stain

Subperineurial Edema: Endoneurial vessels


Gomori trichrome stain

Gomori trichrome stain
Endoneurial vessels: Large with large endothelial nuclei

Gomori trichrome stain

Gomori trichrome stain


Toluidine blue stain

Toluidine blue stain

Toluidine blue stain
Endoneurial vessels: Large with large endothelial nuclei

Toluidine blue stain

Toluidine blue stain

Toluidine blue stain


C5b-9 stain
C5b-9 complement: Deposited on endoneurial microvessels (capillaries)

Subperineurial Edema: Ultrastructure
  Contains
    Granular, Proteinaceous fluid
    Cells: Few fibroblasts & Macrophages
  Bordered by
    External: Perineurium
    Internal: Endoneurial collagen, axons & Schwann cells
Subperineurial space: Contains
  Granular material
  Small amounts of collagen
  Rare macrophages & fibroblasts

Endoneurial microvessel (capillary) within region of subperineurial edema
  Contains
    Endothelial cell (Large): In lumen
    Pericyte: In vessel wall
    Fibroblast: Outside vessel

Subperineurial edema
  Space under perineurium: Contains granular, mostly acellular material

Subperineurial edema
  Axon loss pattern: Differential fascicular
    Varies within and among fascicles
    Some regions (Left fascicle) have complete loss of large and small axons
    Other regions (Right) have relatively preserved populations of large and small axons.

Neurofilament stain

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3/25/2017