Eosinophilic Vasculitis
Vasculitic Pathology
Serum testing:
ANCA+ with pANCA- & cANCA-; RNP mildly+
![](../pics/biopsy/vasculitis/eovasc/eosgranvaschelp.jpg)
H&E stain
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Vessels
Wall: Damaged; Cellular
Lumen: Lost
Epineurium
Eosinophils (Scattered) & other Cells
Nerve fascicle
Subpoerineurial edema
![](../pics/biopsy/vasculitis/eovasc/eosgranvascepineurvesscrlp2.jpg)
Congo red stain
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![](../pics/biopsy/vasculitis/eovasc/sgranvascvvglp.jpg)
VvG stain
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Vessels
Wall: Damaged; Cellular; No fibrils
Endothelial cells: Large
Lumen: Lost
![](../pics/biopsy/vasculitis/eovasc/eosgranvascepineurvesshe.jpg)
H&E stain
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Vessels
Wall: Damaged; Cellular; No fibrils
Endothelial cells: Large
Lumen: Lost
![](../pics/biopsy/vasculitis/eovasc/eosgranvascvvgvhp.jpg)
VvG stain
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![](../pics/biopsy/vasculitis/eovasc/eosgranvascepineursmvessvvg2.jpg)
VvG stain
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Vessels: Three types
Within cell focus: No fibrils; Endothelial cells large
Vein: No fibrils
Vascular remnants: Clustered
![](../pics/biopsy/vasculitis/eovasc/eosgranvascepineurvesscrhp.jpg)
Congo red stain
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Inflammatory Cell Focus
Contains scattered eosinophils
![](../pics/biopsy/vasculitis/eovasc/eosgranvascepineurinflamgthp.jpg)
Gomori trichrome stain
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![](../pics/biopsy/vasculitis/eovasc/eosgranvascepineurgranvvg.jpg)
VvG stain
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Granuloma: Epineurial
All cells in focus stain for acid phosphatase
![](../pics/biopsy/vasculitis/eovasc/eosgranvascacpmp.jpg)
Acid phosphatase stain
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![](../pics/biopsy/vasculitis/eovasc/eosgranvascacphp.jpg)
Acid phosphatase stain
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Vasculopathy: Smaller Epineurial Vessels
![](../pics/biopsy/vasculitis/eovasc/eosgranvascepineursmvessvvg.jpg)
VvG stain
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Epineurial Vessels: Small
Surrounded by: Cells; Pale epineurial connective tissue
![](../pics/biopsy/vasculitis/eovasc/eosgranvascepineurvesseoshe.jpg)
H&E stain
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Epineurial Vessels: Neovascularization
Multiple small vessels within region of larger vessels
![](../pics/biopsy/vasculitis/eovasc/neovasculex.jpg)
UEA I stain
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Histiocytes in several structures
Epineurial Vessel: Acid phosphatase stained connective tissue inside fibril layer
Perineurium around small nerve fascicle (Arrow): Histiocytic cells
Epineurial connective tissue: Scattered histiocytic cells
![](../pics/biopsy/vasculitis/eovasc/eosgranvascperineuracpmpar.jpg)
Acid phosphatase stain
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![](../pics/biopsy/vasculitis/eovasc/eosgranvascspehelp.jpg)
H&E stain
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Subperineurial Edema
Pale-stained region under Perineurium
![](../pics/biopsy/vasculitis/eovasc/eosgranvascspegtlp.jpg)
Gomori trichrome stain
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Eosinophils: Within area of subperineurial edema
![](../pics/biopsy/vasculitis/eovasc/eosgranvascspeeoshehp.jpg)
H&E stain
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Wallerian Degeneration
![](../pics/biopsy/vasculitis/eovasc/eosgranwdvvgar.jpg)
VvG stain
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Wallerian Degeneration: Early
Myelin sheath
Pale; Vesicular; Irregular (Arrow, Above)
Acid phosphatase stain (Below)
See:
Intramuscular nerve
![](../pics/biopsy/vasculitis/eovasc/eosgranwdacp.jpg)
Acid phosphatase stain
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Wallerian Degeneration: Intramuscular Nerve
![](../pics/biopsy/vasculitis/eovasc/egpamuscwdvvg.jpg)
VvG stain
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![](../pics/biopsy/vasculitis/eovasc/egpamuscwdvvg2.jpg)
VvG stain
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Wallerian Degeneration: Early
Myelin sheath
Pale; Vesicular; Irregular (Arrow, Above)
Acid phosphatase stain (Below)
![](../pics/biopsy/vasculitis/eovasc/egpamuscwdacp.jpg)
Acid phosphatase stain
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Axon Loss
Differential: Intrafasciclar
More loss of large (Green) axons in some regions
NCAM-stained Schwann cells: Empty (Red) without associated axons
Active: Punctate or Irregular neurfilament staining
![](../pics/biopsy/vasculitis/eovasc/egpawdNF(g)NCAM(r).jpg)
Neurofilament (Green) + NCAM (Red)
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Axon Loss: Acute
Loss of large axons within pale areas (Myelin)
Punctate or Irregular neurofilament staining
![](../pics/biopsy/vasculitis/eovasc/eosgranvascwdnfmp.jpg)
Neurofilament stain
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Axon Loss: Acute
Regions of myelin abnormally express NCAM
NCAM stain
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![](../pics/biopsy/vasculitis/eovasc/egpawdNF(g)MBP(r).jpg)
Neurofilament (Green) + MBP (Red)
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Axon Loss: Acute
Regions of myelin (MBP above or P0 below) have no axons
![](../pics/biopsy/vasculitis/eovasc/egpawdNF(g)P0(r).jpg)
Neurofilament (Green) + P0 (Red)
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Eosinophilic Vasculitis: Muscle features
![](../pics/biopsy/vasculitis/eovasc/egpamuschelp.jpg)
H&E stain
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Histiocytic Vasculitis
Vessel location: Perimysium
Perivascular cells: Mostly histiocytes
![](../pics/biopsy/vasculitis/eovasc/egpamuschemp.jpg)
H&E stain
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Eosinophilic Vasculitis
Fibrinoid Necrosis: Inside fibril layer
Fibril layer: Irregular damaged
Surrounding vessel wall: Contains many histiocytes; Little other structure
![](../pics/biopsy/vasculitis/eovasc/eovasclvvvg.jpg)
VvG stain
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![](../pics/biopsy/vasculitis/eovasc/eosgranvascmuscacp.jpg)
Acid phosphatase stain
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Histiocytic Vasculitis
Vessel location: Perimysium
Perivascular cells: Mostly histiocytes
![](../pics/biopsy/vasculitis/eovasc/eosgranvascmuscacpvhp.jpg)
Acid phosphatase stain
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![](../pics/biopsy/vasculitis/eovasc/egpamusccd4.jpg)
CD4 stain
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Histiocytic Vasculitis
Vessel location: Perimysium
Perivascular cells: Often stain for CD4 & MxA; Few stain for CD8
![](../pics/biopsy/vasculitis/eovasc/egpamuscmxa.jpg)
MxA stain
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![](../pics/biopsy/vasculitis/eovasc/egpamusccd8.jpg)
CD8 stain
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Eosinophilic Vasculitis: Myopathic features
![](../pics/biopsy/vasculitis/eovasc/egpamusche.jpg)
H&E stain
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Muscle Fibers
Sizes: Moderately varied
Internal nuclei: Some fibers
![](../pics/biopsy/vasculitis/eovasc/egpamuscvvg.jpg)
VvG stain
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![](../pics/biopsy/vasculitis/eovasc/egpamuscacp.jpg)
Acid phosphatase stain
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Muscle Fibers: Internal Architecture
Cytoplasmic aggregates
Acid phosphatase positive (Above)
Contain LC3 (Autophagy marker; Below)
![](../pics/biopsy/vasculitis/eovasc/egpamusclc3.jpg)
LC3 stain
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![](../pics/biopsy/vasculitis/eovasc/egpamuscmhc1.jpg)
MHC Class I stain
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Muscle fibers
MHC1 upregulation
Perimysial vessels
Irregular fragments without lumens (Below; Arrow)
![](../pics/biopsy/vasculitis/eovasc/egpamuscpmvessmhc1mpar.jpg)
MHC Class I stain
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C5b-9 deposition
Location: Connective tissue, Endomysial & Perimysial
![](../pics/biopsy/vasculitis/eovasc/egpamuscc5b9.jpg)
C5b-9 stain
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![](../pics/biopsy/vasculitis/eovasc/egpamusccd163.jpg)
CD163 stain
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Histiocytic markers
CD163 histiocytes: Scattered in endomysium & perimysium (Above)
HAM56: Unusual distribution on endomysium & around surface of muscle fibers (Below)
![](../pics/biopsy/vasculitis/eovasc/egpamuscHAM56.jpg)
HAM56 stain
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Eosinophilic Vasculitis
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7/3/2023