MUSCLE
Amyloid myopathy
- Amyloid (Red): Locations
- Extracellular
- Tissues
- Muscle fibers: Around surface
- Perimysium
- Vessel walls
- Amyloid properties: Apple green birefringence of amyloid
- Amyloid Components
- Hereditary
- Apolipoprotein A1, Apolipoprotein A4, Apolipoprotein E, Serum amyloid P component
- No Anoctamin-5 or Dysferlin
- Acquired: Amyloidogenic proteins (AL & SSA)
- Amyloid in IM-VAMP (IBM)
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Congo red
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Congo red (Polarized light) |
Congo red (Fluorescence) |
Amyloid Muscle Fibers
Amyloid surrounding, and on, muscle fibers
- Mild pathology (Above): Thin layer of amyloid around normal sized muscle fiber
- More severe changes (Below)
- Thick deposit of amyloid around, and on, small muscle fibers
- Nuclei and NADH-positive membranes are present in regions of amyloid deposits
- Myofibrillar contractile apparatus (ATPase staining) is absent from areas of amyloid deposition but present in the center of fibers
Congo red
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Congo red (Polarized light) |
Congo red (Fluorescence) |
Muscle fiber pathology in amyloid myopathy
- Abnormal nuclei: In ring within muscle fibers
- Irregular deposits of amyloid: On muscle fibers outside nuclear ring
Congo red
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Congo red stain
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Congo red stain |
Congo red stain (Polarized light)
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Congo red, polarized light
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Congo red
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Amyloid Fibers
Muscle fiber pathology in amyloidosis
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H&E stain
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H&E stain
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Gomori trichrome
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VvG
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Congo red
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Amyloid Fibers
VvG
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Congo red
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Congo red: Fluorescence
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Amyloid Fibers
ATPase pH 9.4
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ATPase pH 9.4
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NADH
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Dystrophin
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Surface membrane (Above) & Basal lamina (Below): Thickened & reduplicated around muscle fibers
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α2-Laminin
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IgAκ M-protein: Amyloid
Congo red
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Amyloid deposits in perimysium and along the perimysial surface of muscle fibers
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Congo red
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IgGλ M-protein: Amyloid
Congo red
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Congo red
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Congo red
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Congo red
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NERVE: Amyloid
Patterns of axon loss
Amyloid deposition in nerve may be
Amyloid: Distribution
- Organs: Many
- Vessels: Common
- More abundant in large nerves
Severe Axon Loss
Marked axon loss
Small axons are even more involved than large axons
See: Control nerve
Neurofilament stain
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Neurofilament stain
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Moderate axon loss
Differential fascicular loss: More axon loss in some areas than others
Neurofilament stain
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Moderate axon loss
VvG stain
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More loss of small axons, than larger myelinated axons
Neurofilament stain
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Large axons: Moderate loss
Small axons: Severe loss
Neurofilament stain
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NCAM stain
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Non-myelinating Schwann cells
Normal or Increased Numbers
NCAM stain
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Toluidine blue stain
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Moderate axon loss
More loss of small, than large, myelinated axons
Subperineurial edema in some fascicles
Toluidine blue stain
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Toluidine blue stain
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Toluidine blue stain
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Amyloid Deposition
Relative preservation of larger myelinated axons
Amyloid Deposition
Capillary walls: Thick
Sub-Perineurial edema
H&E stain
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Congo red stain
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Capillary walls
Contain red-stained amyloid
Amyloid is birefringent
Congo red stain
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Endoneurial amyloid, Multifocal, often near endoneurial vessels (Arrow)
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Congo red stain
Congo red stain |
Amyloid: Amorphous deposits surround endoneurial microvessels
Congo red stain
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Toluidine blue stain
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Amyloid: Amorphous deposits around endoneurial microvessels
Toluidine blue stain
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Endoneurial amyloid, Diffuse
Congo red stain |
Congo red stain |
Toluidine blue stain |
Amyloid: Amorphous deposits in endoneurium
Toluidine blue stain |
SUBPERINEURIAL AMYLOID (Arrow)
Congo red stain |
Moderate sized vessels: Amyloid
Vessels in Perimysium & Epineurium: May have amyloid deposits
Congo red stain
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Congo red stain (± Polarized light)
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Congo red stain (Polarized light)
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Amyloid in vessel walls
Red-Stained
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Birefrengence ± Polarization
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Amyloid in vessel wall
Apple green
with polarized light.
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Amyloid: Artery
Congo red stain |
Amyloid: Vein + Perimysium
Congo red stain |
Amyloid: Fibrils
From: J Karamchandani |
Nerve
H&E stain |
Amyloid: Amorphous clusters in endoneurium
H&E stain |
H&E stain |
Amyloid: Amorphous, rounded clusters in endoneurium
Gomori trichrome stain |
VvG stain |
Toluidine blue stain |
Amyloid
Amorphous, rounded clusters in endoneurium
Amyloid surrounded by pale cell-free regions
Toluidine blue stain |
Congo red stain |
Amyloid
Amorphous, rounded clusters in endoneurium
Perineurial deposition, scattered
Congo red stain |
Amyloid
Surrounds endoneurial microvessel
Congo red stain |
Amyloid (TTR Val30Met): Muscle
H& E stain |
Chronic denervation & Reinnervation, Progressive
Grouped atrophy
Larger muscle fibers are hypertrophied
VvG stain |
ATPase pH 9.4 stain |
Chronic denervation & Reinnervation, Progressive
Fiber type grouping
ATPase pH 4.3 stain |
ATPase pH 4.3 stain |
Chronic denervation & Reinnervation, Progressive
Muscle fibers in region of grouped atrophy
Varied degrees of immaturity (Type 2C)
Esterase positive cytoplasm
Esterase stain |
Congo red stain |
Amyloid deposits
Most prominent in smaller perimysial vessels
Congo red stain |
Amyloid (TTR Thr60Ala): Muscle
H&E stain |
Congo red stain |
Amyloid deposits
Most prominent in connective tisue & around muscle fibers
Congo red stain |
Congo red stain |
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Amyloidosis
10/27/2023