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Acute Nutritional Neuropathy

General Axons   Myelin Loss   Schwann cell pathology   Myelin pathology   Unmyelinated Wallerian Degeneration Cell processes

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H&E stain

Myelinated Axons
  Reduced number
  Damaged myelin (Loss of staining)

H&E stain

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Gomori trichrome stain

Myelinated Axons
  Reduced number
  Damaged myelin (Loss of red color)

Gomori trichrome stain

Gomori trichrome stain

Myelinated Axons
  Reduced number
  Damaged myelin (Loss of staining)

VvG stain

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Acute Nutritional Neuropathy: Wallerian Degeneration

Acid phosphatase stain

Myelin Sheaths
  Diffusely stained by acid phosphatase

Acid phosphatase stain

Acid phosphatase stain

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Neurofilament stain

Myelinated Axons
  Loss of neurofilament stain
  Neurofilament stain: Diffuse through some myelin sheaths
Unmyelinated Axons
  Preserved numbers

Neurofilament stain

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Neurofilament (Green), Myelin basic protein (Red) stain

Neurofilament stained axons in sural nerve (Yellow)
  Lost within many MBP stained myelin sheaths (Red)
  Unmyelinated Axons: preserved numbers (Green)

Neurofilament (Green), Myelin basic protein (Red) stain

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Neurofilament (Green), Myelin basic protein (Red) stain

Neurofilament stained axons in anterior interosseus nerve (Yellow)
  Lost within some MBP stained myelin sheaths (Red)
  Unmyelinated Axons: preserved numbers (Green)

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Neurofilament (Green), Myelin basic protein (Red) stain

Acute & Chronic loss of myelinated axons in sural nerves
  Acute loss: MBP-stained myelin sheaths without axons
  Chronic loss: Reduced numbers of MBP-stained myelin sheaths

Neurofilament (Green), Myelin basic protein (Red) stain

Neurofilament (Green), Myelin basic protein (Red) stain

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C5b-9 stain

Myelin Degeneration with Axon loss
  C_5b-9 stains in & around myelin sheaths

C5b-9 stain

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From: R Schmidt

Myelin Damage & Ovoids
Schwann Cells
  Some contain Lipid debris

From: R Schmidt

From: R Schmidt

Myelin Damage: Lipid Droplets & Ovoids in Schwann cells

From: R Schmidt

From: R Schmidt

Myelin Damage: Lipid Droplets & Ovoids in Schwann cells

From: R Schmidt

From: R Schmidt

Myelin Damage: Lipid Droplets & Myelin debris in Schwann cells

From: R Schmidt

From: R Schmidt

Myelin Damage: Lipid Droplets & Myelin debris in Schwann cells

From: R Schmidt

From: R Schmidt

Myelin Damage: Lipid Droplets & some Myelin debris in Schwann cells

From: R Schmidt

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Lipid Droplets in an endoneurial cell

From: R Schmidt

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From: R Schmidt

Lipid Droplets & Myelin debris segregated in different Schwann cell processes

From: R Schmidt

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Cell Processes: Other

From: R Schmidt

From: R Schmidt

From: R Schmidt

From: R Schmidt

From: R Schmidt

From: R Schmidt

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From: R Schmidt

From: R Schmidt

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Axons: Large & Abnormal Structure with no surrounding Myelin

From: R Schmidt

Demyelinated Axons
  Contain: Filaments; Mitochondria; Vesicles
  Surrounded by: Thin Schwann cell processes containing Myelin, or Lipid, Debris

From: R Schmidt

From: R Schmidt

Demyelinated Axon
  Contain: Filaments; Vesicles
  Surrounded by: Thin Schwann cell processes containing Myelin, or Lipid, Debris

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From: R Schmidt

Demyelinated Axon
  Contain: Filaments; Vesicles
  Surrounded by: Multiple small Schwann cell processes

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From: R Schmidt

Demyelinated Axon
  Contains: Filaments; Vesicles
  Surrounded by: Multiple small Schwann cell processes
Neighboring Macrophage
  Contains lipid droplets

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From: R Schmidt

Demyelinated Axon
  Contains: Filaments; Vesicles
  Surrounded by: Multiple small Schwann cell processes

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From: R Schmidt

Demyelinated Axon
  Contains: Filaments; Vesicles
  Surrounded by: Multiple small thin processes

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From: R Schmidt

Demyelinated Axon
  Contains: Filaments, Densely packed
  Surrounded by: Schwann cell containing many vesicles

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From: R Schmidt

Demyelinated Axons
  Contains: Filaments; Vesicles
  Surrounded by
    Neighboring Thin Schwann cell processes containing Debris
    Pseudo- or immature onion bulb: Concentric layers of Schwann cell processes & connective tissue

From: R Schmidt

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From: R Schmidt

Schwann cells around Demyelinated Axons: Contain Myelin Degradation Products

From: R Schmidt

From: R Schmidt

Demyelinated Axon
  Contain: Filaments; Vesicles
  Surrounded by: Thin Schwann cell processes containing Myelin Debris, or Lipid Droplets

From: R Schmidt

From: R Schmidt

Demyelinated Axon
  Contain: Filaments; Vesicles
  Surrounded by: Schwann cells containing Myelin Debris, or Lipid Droplets

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From: R Schmidt

Demyelinated Axon
  Contain: Filaments; Vesicles
  Surrounded by: Schwann cells containing Myelin Debris, or Lipid Droplets
Neighboring Macrophage (Left)
  Contains lipid droplets

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From: R Schmidt

Demyelinated Axon
  Contain: Filaments; Vesicles
  Surrounded by: Schwann cells containing Myelin Debris, or Lipid Droplets

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Myelin Pathology: Early

From: R Schmidt

Histiocyte (Macrophage) (Top)
  Contains lipid droplets
Small Myelinated Axon (Below histiocyte)
  Associated with Schwann cell & its nucleus
Larger Myelinated Axon (Left)
  Schwann cell cytoplasm outside myelin sheath contains debris: Suggests early damage to myelin
Unmyelinated Axons, small (Bottom, Middle)
  Surrounded by processes of non-myelinating Schwann cells
Fibroblast processes
  Dark, thin processes along bottom of image

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From: R Schmidt

Myelin & Schwann cell Pathology, Early: 3 Myelinated axons
  Myelinated axons associated with pale & increased Schwann cell cytoplasm outside myelin sheath
  Uncompacted myelin layers (Double membranes) on outside of myelin sheath (Top Right)
Unmyelinated axons (Bottom)
  Surrounded by moderately pale Schwann cell processes

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From: R Schmidt

Larger Myelinated Axon (Left)
  Schwann cell cytoplasm outside myelin sheath contains debris: Suggests early damage to myelin (Also see below)
Wallerian Degeneration (Right)
  Schwann cell contains myelin debris & lipid droplets
  Axon has degenerated & is not visible
Macrophage-like cell (Bottom; Center)
  Contains debris in cytoplasm

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From: R Schmidt

Larger Myelinated Axons (Above & Below)
  Schwann cell cytoplasm outside myelin sheath contains debris: Suggests early damage to myelin (See above)

From: R Schmidt

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From: R Schmidt

Myelin sheath, Irregular
  Irregular myelin-like structures outside myelin sheath

From: R Schmidt

From: R Schmidt

Myelin sheath, Irregular
  Irregular Myelin & Schwann cell structure between axon & Myelin sheath

From: R Schmidt

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From: R Schmidt

Myelin sheath, Irregular
  Associated Schwann cell cytoplasm outside myelin sheath contains debris & pi granules

From: R Schmidt

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From: R Schmidt

Myelinated Axons
  A few have preserved structure

From: R Schmidt

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From: R Schmidt

Myelinated Axons
  A few have preserved structure

From: R Schmidt

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Non-Myelinating Schwann Cells & Unmyelinated Small Axons

NCAM stain

Non-myelinating Schwann cells
  Normal numbers

NCAM stain

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Neurofilament (Green), NCAM (Red) stain

Unmyelinated Axons
  Normal numbers: Few or no empty (Red) Schwann cells

Neurofilament (Green), NCAM (Red) stain

Neurofilament (Green), NCAM (Red) stain

Unmyelinated Axons
  Normal numbers: Few or no empty (Red) Schwann cells

Neurofilament (Green), NCAM (Red) stain

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Neurofilament (Green), NCAM (Red) stain

Unmyelinated Axons
  Mild loss in this nerve: Scattered empty (Red) Schwann cells

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From: R Schmidt

Unmyelinated Axons
  Numbers: Relatively preserved; Several per Schwann cell
Non-myeliinating Schwann cells
  May have pale cytoplasm (Below)

From: R Schmidt

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Neurofilament (Green)stain

Small Axons
  May appear beaded
  Numbers: Mildly reduced

Neurofilament (Green), NCAM (Red) stain

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1/13/2026