Neuromuscular

Nerve Specific (Non-Systemic) Inflammatory Vasculopathic Neuropathy (NSVN)

Pathology features

H&E stain
Perivascular Inflammation
  Surrounds small epineurial vessels
  Larger epineurial Arteries & Veins: Varied pathology
    May be Normal (Below) or Damaged (Above)
  Epineurium: May have neovascularization (Above)

Congo red stain


H&E stain
Perivascular Inflammation
  Surrounds small epineurial vessels
  Larger epineurial arteries & veins: Varied pathology
    May be Normal (Below) or Damaged (Above)
  Epineurium & Vessel walls: May have neovascularization (Above)

H&E stain


H&E stain
Perivascular Inflammation: T-cells
  Surrounds small epineurial vessels
  Contains CD4 & CD8 lymphocytes

CD4 stain


CD8 stain

Histiocytes in & near Epineurial Vessel walls

Acid Phosphatase stain

NSVN: Neovascularization

H&E stain

H&E stain

NSVN: Large vessel damage

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NSVN: Endoneurium

H&E stain
NSVN: Nerve Edema
  Present in subperineurial & endoneurial regions between fascicles

Gomori trichrome stain

NSVN: Axons

VvG stain
NSVN: Differential Fascicular Involvement
  Varied Loss (Above) & Degeneration (Below) of axons within & among fascicles

Acid Phosphatase stain

ATPase stain pH 4.3
  Reduced staining in endoneurium
  Vessels in endoneurium are normall stained

ATPase pH 4.3 stain

NSVN: Wallerian degeneration

Neurofilament stain
Axon loss: Acute
  Granular, punctate staining in areas that previously contained large myelinated axons

Neurofilament stain

Wallerian degeneration
  Irregularly stained myelin sheaths

VvG stain

Wallerian degeneration
  Schwann cells associated with degenerating axons abnormally express NCAM

NCAM stain

Wallerian degeneration
  Acid phosphatase stains phagocyticx endoneurial cells

Acid Phosphatase stain


Toluidine blue stain
Wallerian degeneration
  Phagocytic endoneurial Schwann cells & Histiocytes contain myelin debris & lipid droplets

Toluidine blue stain

Toluidine blue stain

NSVN: Acutely denervated muscle
  Muscle fibers: Midly small; Myonuclei are mildly large
NSVN: Acutely denervated muscle
  Muscle fibers: Irregular staining of cytoplasm
NSVN: Acutely denervated muscle
  Muscle fibers: Irregular internal architecture

Endomysial histiocytes near capillaries

Return to Muscle biopsies

2/13/2022