Neuromuscular

HIV: Vasculitis

Nerve
  Artery damage
  Epineurial vessels, Small
Muscle involvement
  Veinitis
  Also see: IM-VAMP pathology

HIV: Arteritis

Arteritis during HIV

Toluidine blue stain
Epineurium
  Artery
    Damaged structure
      Fibril layer: Irregular or Interrupted
      Connective tissue inside fibril layer
    Neovascularization
    Histiocytes in wall
    No lumen
  Epineurial connective tissue
    Neovascularization
    Structure: Fragmented, Pale stained
    Hemosiderin
 Endoneurium
  Axon loss
    Myelinated axons: Severe (Above)
    Unmyelinated axons: May be relatively preserved
    Wallerian degeneration: Early or Later stage
  Subperineurial Edema
  Microvessels: Prominent endothelium, especially during Wallerian degeneration
  Pale staining: Patchy

Congo red

H&E stain
Arteritis
  Artery (Above, White arrow): Occluded; Wall damaged; Histiocytic cells (Below; White Arrow)
  Endoneurium: Pale regions (Above, Black arrow); Moderately prominent microvessels; Histiocytes, scattered (Below; Black Arrow)

Acid phosphatase
Epineurial Artery
  Increased cells in most of wall
  Neovascularization
  Lumen: Occluded

H&E stain
Hemosiderin
  Deposits in epineurium (Arrow)

H&E stain
Neovascularization: Within lumen of Occluded artery

VvG stain
Epineurial Artery (Serial sections)
  Fibril layer: Irregular (Arrow)
  Neovascularization
  Lumen: Occluded
  Connective tissue around artery: Damaged in some areas (Below)

VvG stain

Toluidine blue stain
Epineurial Artery
  Neovascularization
  Connective tissue around artery: Damaged in some areas; Irregular structure

Alkaline phosphatase stain
Epineurial Artery
  Neovascularization: New vessels within larger vessel stained with alkaline phosphatase

Toluidine blue stain
Epineurial connective tissue: Neovascularization & Fragmentation

Toluidine blue stain

Toluidine blue stain
Epineurial connective tissue: Fragmentation

Gomori trichrome

Congo red

Congo red
Occluded Artery
  No lumen
  Histiocytes within vessel wall: In patchy regions & Scattered
  Lymphocytes: Not prominent

Acid phosphatase

Acid phosphatase
Artery: Abnormal
  Many cells all through wall

Toluidine blue stain
Wallerian Degeneration: Myelinated Axon loss, Later stages
  Myelinated axons: Severe loss
  Remaining myelin fragments: Reduced staining (Arrows)

Gomori trichrome stain

Gomori trichrome stain
Axon loss: Later stages
  Myelinated axons: Severe loss
  Myelin remnants: Minimal staining on Gomori trichrome & VvG (Arrows)

VvG stain
Axon loss
  Myelinated axons: Severe loss
Perineurium
  Normal

Toluidine blue stain

Acid phosphatase stain
Axon loss: Later stages of Wallerian degeneration
  Histiocytic cells scattered in endomysium (Above)
  Probable histiocytic cells around an endoneurial microvessel (Below; Arrow)

Congo red stain
Complement C5b-9 stain
  Wallerian degeneration: Present in endomysium
  Endomysial microvessels: Mild staining

C5b-9 stain

HIV: Inflammatory Vasculopathy, Small Epineurial Vessels (Venitis in muscle)


H&E stain
Epineurial Vessels: Inflammatory Vasculopathy
  Lymphocytes: Present around & within walls of small epineurial vessels
  Epineurial connective tissue: Neovascularization
Endoneurium
  Myelinated axons: Wallerian Degeneration

VvG stain
Epineurial connective tissue: MHC I
  Increased staining
Epineurial Perivascular cells: MHC I
  Increased staining

MHC I stain

H&E stain
HIV: Inflammatory vasculopathy
  Inflammation: Surrounds small epineurial vessels
  MHC I
    Stains
      Cells around epineurial small vessels
      Epineurial connective tissue
  Wallerian Degeneration of Myelinated Axons: Common

MHC I stain
Small Vessel Inflammatory Vasculopathy: Epineurial Neovascularization

ATPase pH 4.3 stain
Neovascularization
  New vessels
    Small; Multiple
    Stained by: ATPase; Alkaline phosphatase
  Associated connective tissue: Pale; Fragmented; Cellular, including histiocytes

VvG stain

H&E stain
Neovascularization: Epineurial

VvG stain

Gomori trichrome stain
Neovascularization: Epineurial

Gomori trichrome stain

Acid phosphatase stain
Histiocytes
  Often present in epineurial connective tissue & around vessels in regions of neovascularization

Acid phosphatase stain
Endothelium in new Epineurial vessels stains with Alkaline phosphatase

Alkaline phosphatase stain

ATPase pH 4.3 stain
Endothelium in new Epineurial vessels stains with ATPase

ATPase pH 4.3 stain

ATPase pH 4.3 stain
MHC I positive cells & epineurium

MHC I stain
Wallerian Degeneration: Early, Active & Acute

Gomori trichrome stain
Wallerian Degeneration
  Myelin: Irregular structure or Pale stain

Gomori trichrome stain

Gomori trichrome stain
Wallerian Degeneration
  Myelin: Irregular structure

VvG stain
Wallerian Degeneration (Early)
  Histiocytes: Scattered in endoneurium

Acid phosphatase stain
Wallerian Degeneration (Early)
  NCAM: Mild staining of myelin

NCAM stain
Wallerian Degeneration (Early)
  Neurofilament staining of myelinated axons: Lost or fragmented
  Neurofilament staining of unmyelinaterd axons: Relatively preserved

Neurofilament stain

Toluidine blue stain
Wallerian Degeneration (Early)
  Myelin structure: Irregular
  Large myelin fragments: Present in cytoplasm of large "Degradative" Schwann cells

Toluidine blue stain

Toluidine blue stain
Wallerian Degeneration (Early)
  Myelin structure: Irregular
  Large myelin fragments: Present in cytoplasm of large "Phagocytic" Schwammm cells

Toluidine blue stain

Toluidine blue stain
Wallerian Degeneration (Early)
  Myelin structure: Irregular
  Large myelin fragments: Present in cytoplasm of large "Phagocytic" Schwammm cells

Toluidine blue stain

Neurofilament (Green) + MBP (Red)
Wallerian Degeneration (Early)
  Neurofilament staining of myelinated axons
    Lost or fragmented
    MBP & P0 stained myelin have no associated axons
  Neurofilament staining of unmyelinaterd axons: Relatively preserved

Neurofilament (Green) + P0 (Red)

Neurofilament (Green) + NCAM (Red)
Wallerian Degeneration (Early)
  Neurofilament staining of myelinated axons
    Lost or fragmented
  Neurofilament staining of unmyelinaterd axons
    Some Loss: Empty (red) non-myeliating Schwann cells
Myelin in Peripheral Nerve: 2 types
  Small myelin sheaths (Green): Contain only P0
  Large myelin sheaths (Yellow): Contain both P0 & MBP

P0 (Green) + MBP (Red)
Wallerian Degeneration
  Endothelial cells in Endoneurial microvessels: Often large

H&E stain

H&E stain
Wallerian Degeneration
  Endothelial cells in Endoneurial microvessels: Often large

H&E stain

HIV: Inflammatory Veinopathy

Same patient as: Small Vessel Inflammatory Neuropathy

VvG stain
Perimysial Veins
  Outer fibril layer: Damaged & Incomplete
  Inner layers: Pale & Cellular

VvG stain

VvG stain
Perimysial Veins
  Outer fibril layer: Damaged & Incomplete
    Inflammatory cells: Present around outside of vein
  Inner layers: Pale & Cellular
Perimysial Artery: Normal

VvG stain
Perimysial Veins
  Histiocytic Inflammatory cells: Present around periphery of vein

Acid phosphatase stain
Perimysial Veins
  Inflammatory cells: Present around periphery of vein & In perimysium

Congo red stain

Gomori trichrome stain
Perimysial Cell Foci
  Contain scattered esterase-positive histiocytes (Below)

Esterase stain

H&E stain
HIV-Vasculitis: Muscle fiber involvement
  Morphology: Mostly normla

H&E stain

MHC I stain
HIV-Vasculitis: Muscle fiber involvement
  MHC I: Upregulated on muscle fiber surfaces

MHC I stain
HIV-Vasculitis: Capillaries
  Sizes: Midly large
  Numbers: Normal or Mildly increased

UEA I stain
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6/1/2023