Neuromuscular

VASCULITIS

Axons
  Differential fascicular loss
Early lesion
Fibrinoid necrosis
Hemosiderin
Inflammation
  Other
Syphilis
Vessels
  Intimal proliferation
  Large
  Normal
  Occluded
  Recanalization
  Epineural neovascularization
Vein & Artery: Occluded
  Nerve showed: Differential fascicular loss of axons



VASCULITIC LESION: EARLY


H&E stain

Acid phosphatase stain

Acid phosphatase stain

FIBRINOID NECROSIS


H&E stain

H&E stain


VvG stain
Vasculitis
  Fibrinoid Necrosis: Thick orange layer in center of vessel
  Vessel wall
    Thickness: Increased
    Fibril structure: Irregular or absent
  Neovascularization: Epineurial; Around vessel

VvG stain

Vasculitis
  Fibrinoid Necrosis: Blue-stained layer near lumen of vessel
  Vessel wall: Thickened
  Hemosiderin: IN connective tissue around vessel

Alcian blue/Nuclear fast red

Vasculitis
  Fibrinoid Necrosis: Thick layer in center of vessel near lumen
  Vessel wall: Cellular; Reduced connective tissue

Toluidine blue stain

CONNECTIVE TISSUE (Perimysium or Epineurium) NEAR VESSELS

Alkaline phosphatase staining

Alkaline phosphatase stain

Alkaline phosphatase stain

Hemosiderin


NADH stain
Perimysial vessels: Surrounded by hemosiderin deposits in connective tissue

Congo red stain

Epineurium: Hemosiderin deposits; Neovascularization

Congo red stain

VASCULITIS: Occluded Vessels & Lumen pathology


H & E stain

H & E stain

H & E stain

VvG stain

Acid phosphatase stain

Perimysial arteriole: Occluded, Early neovascularization

VvG stain

Perimysial vessel: Occluded, Early neovascularization

Gomori trichrome stain

Vessel wall: Thickened around area of occlusion

Toluidine blue stain

Toluidine blue stain

VASCULITIS (Chronic): Neovascularization; Multiply recanalized Vessels


VvG stain

H & E stain

Alkaline phosphatase stain

Gomori trichrome stain
Recanalization (Multiple lumens surrounded by endothelium) within intermediate-sized vessels with no elastin lamina

Elastin layer & fibrils: VvG stain

VvG stain
Artery: Damage
Connective tissue & Neovascularization: Proliferation inside elastin layer
Elastin layer: Abnormal in a region of vessel wall

VvG stain
A neighboring vein has normal wall structure



VvG stain
Connective tissue proliferation & Recanalization inside elastin layer
Elastin fibrils are reduced in number

VASCULITIS (Chronic & Ongoing): Epineurial neovascularization around Vessels

Differential diagnosis

H&E stain
Neovascularization: New small vessels in pale, hypercellular epineurial connective tissue around large vessels
Fibrinoid necrosis: Wide-stained region around vessel lumen

VvG stain


Congo Red stain
Epineurial connective tissue: Reorganized in region of neovascularization

VvG stain


Acid Phosphatase stain
Histiocytic cells: In epineurium & vessel walls


Alkaline Phosphatase stain
Epineurial vessels & connective tissue: Stains with alkaline phosphatase


Ulex (UEA-I) stain
Epineurial neovascularization: Many epineurial capillaries with endothelium stained by UEA-I


Toluidine blue stain
Epineurium: Abnormal structure & Neovascularization

Endoneurium: Microvessel proliferation

Toluidine blue stain

Epineurial Vessel: Intimal Proliferation


H&E stain
Artery
  Lumen: Connective tissue proliferation

Congo red stain

Neurofilament stain
Artery
  Lumen: Connective tissue proliferation
  Elastic lamina: Damaged & Interrupted

NCAM stain

Acid phosphatase stain
Artery: Intimal proliferation

Gomori trichrome stain

VvG stain

Vasculitis
  Vessel wall: Contains blue mucinoid material inside elastin layer

Alcian blue/Nuclear fast red

Perivascular Inflammation


H&E stain
Vaaculitis: Inflammatory Cells
  Mixture of lymphocytes & histiocytes surrounds vessels

H&E stain

H&E stain

VASCULITIS: Other Inflammatory features


H & E stain

H & E stain
Inflammation patterns
  • Giant cells (Above Left; Arrow) or granulomas may be present
  • Inflammatory cells in vessel wall may be fragmented (Above Right)
  • Eosinophils may be present in cellularity around vessel (Below)

H&E stain
Fibrinoid necrosis: In vessel wall
Eosinophils: In perivascular inflammation


Differential fascicular involvement of nerve
  • Some fascicles have fewer axons than the others

Gomori trichrome stain

VvG stain


Vasculitis: Larger vessels


VvG stain
Vessel Wall Damage
  Elastin fibril lamina: Interrupted
  Intimal proliferation: Increased tissue inside fibril layer (See: Normal)

VvG stain

Abnormal cells in vessel wall

Acid phosphatase stain

Vasculitis: Endoneurium

ATPase stain reduced except onendoneurial vessels

ATPase pH 4.3 stain

Vessels: Intermediate-Sized

Normal
  Muscle
    Fetal
  Nerve
Immune Myopathies
  DM-VP
  RIIM
Vasculitis

Normal Vessels


Nerve: Epineurial Vein & Artery

Artery (Black arrow): Linear fibrils near lumen; Thick wall
Vein (White arrow): Interlaced, thin fibrils around outside of vessel; Thin wall

VvG stain

Epineurial Artery: Normal

Alcian blue stain

Epineurial Vein: Normal
  Vein wall contains less mucopolysaccharide than artery

Alcian blue stain

Muscle: Perimysial Vein & Artery


Artery (Top right): Linear fibrils near lumen; Thick wall
Vein (Bottom left): Interlaced, thin fibrils around outside of vessel; Thin wall

VvG stain

Muscle: Perimysial structural variations

  Vascular Perimysium: Contains intermediate sized arteries & veins
  Avascular Perimysium: Contains connective tissue & fibrils, but no vessels
    DM-VP: Muscle fiber atrophy is most often near avascular perimysium

Elastin
  Forms a continuous ring inside the smooth muscle layer: Most prominent in artery
  Is present in a network outside the smooth muscle layer: Artery & Vein
Vein (Bottom left) & Artery (Top right)

Smooth muscle actin (SMA) (Green) & Elastin (Red) stains

PECAM (Endothelium marker)
  Fibrils inside the smooth muscle layer: Most prominent in artery
Vein (Left) & Artery (Right)

Smooth muscle actin (SMA) (Red) & PECAM (Green) stains


Syphilitic arteritis


Oppenheim 1894

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9/22/2017