Neuromuscular

Local Hypertrophic Neuropathy/N-S HNST

Nerve
  Structure
  Organization
  Axons
  Vessels
  Other
Onion bulb-like structures
  Axons
  Nuclear patterns
  Schwann cells
  Patterns
  Ultrastructure

Nerve: Varied Structure
  Large & Small rounded regions separated by varied amounts of endoneurial connective tissue

H&E stain

N-S HNST Nerve organization


H&E stain
Onion Bulb-like Structures
  Varied sizes
  Scattered in pale endoneurium


Gomori trichrome stain
Onion Bulb-like Structures
  Scattered in pale endoneurium
  Myelinated axons (Red) are present in some areas

Gomori trichrome stain


H&E stain
Onion Bulb-like Structures
  Varied sizes
  Clustered in endoneurium

Gomori trichrome stain

Onion Bulb-like Structures
  ATPase stainining around periphery

ATPase ph 4.3 stain


H&E stain
Onion Bulb-like Structures: Varied Patterns
  Concentric layers of cells & connective tissue

Gomori trichrome stain

VvG stain
Onion Bulb-like Structures
  Concentric cell layers
  Connective tissue: Looser organization in outer layers

VvG stain

Onion Bulb-like Structures: Nuclei Patterns


Congo red stain
Onion Bulb-like Structures
  Surrounded by pale-stained endoneurial regions

Congo red stain
Onion Bulb-like Structures
  Verocay body-like organization in some areas
    Palisades of nuclei separated by fibrillary connective tissue

Congo red stain
Onion Bulb-like Structures
  Some structures have many nuclei

Congo red stain

Onion Bulb-like Structures: Schwann cells (NCAM stain)


NCAM/Gomori stain
Onion Bulb-like Structures: Molecular features
  Cells & concentric processes stain for NCAM: Similar to non-myelinating Schwann cells

NCAM/Gomori stain

Onion Bulb-like Structures: Molecular features
  Cells & concentric processes stain for NCAM
  Some cells co-stain for NCAM & P0 (Yellow): Similar Büngner band cells
Scattered myelinated axons (Red) are present in surrounding endoneurial regions

NCAM (Green)/P0 (Red) stain


CD163 stain
Onion Bulb-like Structures
  Some histiocytic cells are present

From: R Schmidt


Onion Bulb-like Structures: Structural Patterns

Toluidine blue stain
Onion Bulb-like Structures: Varied Patterns
  Concentric layers of cells & basal lamina
  Basal lamina: Looser organization in outer layers

Toluidine blue stain


Toluidine blue stain
Onion Bulb-like Structures: Varied Patterns
  Concentric layers of cells & basal lamina
  Basal lamina: Looser organization in outer layers

Toluidine blue stain

Toluidine blue stain

Basal Lamina Onion Bulb (BLOB) Structures: Ultrastructure


From: R Schmidt
Onion Bulb-like Structures: Components
  Basal lamina layers: Abundant
  Schwann cell processes: Circumferential
  Axons: Central (thin or no myelin) & Few peripheral
  Collagen: Less common than in onion bulbs related to demyelination

From: R Schmidt

From: R Schmidt
Onion Bulb-like Structures: Components
  Basal lamina layers: Abundant
  Schwann cell processes: Circumferential
  Axons: Central (thin or no myelin) & Few peripheral
  Collagen: Less common than in onion bulbs related to demyelination

From: R Schmidt

From: R Schmidt

Onion Bulb-like Structures: Variant
  Circumferential large processes
  Central axon: Thinly myelinated

From: R Schmidt

Onion Bulb-like Structures
  Abundant parallel basal lamina
  Schwann cell processes
  Little collagen

From: R Schmidt

From: R Schmidt

From: R Schmidt
Onion Bulb-like Structures
  Abundant parallel basal lamina
  Schwann cell processes
  Little collagen

From: R Schmidt

From: R Schmidt

From: R Schmidt

Onion Bulb-like Structures: Axons, Central& Other


From: R Schmidt
Onion Bulb-like Structures: Central axons
  Thin, or No, Myelin
  Some structures have no central axons

Neurofilament/Gomori stain
Onion Bulb-like Structures: Axons, Central & Other
  Larger axon: At center of some structures
  Smaller axons: Present in circumferential layers
  Some structures have no central axons

Neurofilament/Gomori stain

Neurofilament/Gomori stain
Onion Bulb-like Structures: Axons, Central & Other
  Larger axon: At center of some structures
  Smaller axons: Present in circumferential layers
  Some structures have no central axons

Neurofilament/Gomori stain

Neurofilament/Gomori stain


Neurofilament(Green)/P0 (Red) stain
Local Hypertrophic Neuropathy/N-S HNST: Molecular components
  P0 (Red) stains some cells in onion bulb-like structures
  Axons: More loss of large than small axons
  Varied degrees of pathology: More axon loss & larger onion bulb like structures in some areas

Neurofilament(Green)/P0 (Red) stain


Neurofilament(Green)/NCAM (Red) stain
Local Hypertrophic Neuropathy/N-S HNST: Molecular components
  NCAM (Red) stains most cells in all onion bulb-like structures
  Small axons are presnt in layers of many onion bulb-like structures
  Axons: More loss of large than small axons

Neurofilament (Green)/NCAM (Red) stain

Neurofilament (Green)/NCAM (Red) stain

Neurofilament(Green)/P0 (Red) stain


From: R Schmidt
Local Hypertrophic Neuropathy/N-S HNST: Central axons, Ultrastructure
  Axons have thin, or no, myelin

From: R Schmidt

From: R Schmidt

Local Hypertrophic Neuropathy/N-S HNST: Axons in regions other than onion bulb-like structures

From: R Schmidt
Some irregularly-shaped large myelinated axons are present

From: R Schmidt


Alkaline phosphatase stain
Local Hypertrophic Neuropathy/N-S HNST
  Endoneurial microvessels: Not increased in number
  This differes markedly from perineuriomas

Alkaline phosphatase stain

Ulex stain

From: R Schmidt

Local Hypertrophic Neuropathy/N-S HNST
  No endoneurial EMA staining

EMA stain

Local Hypertrophic Neuropathy/N-S HNST
  Büngner band cells associated with collagen pockets

From: R Schmidt

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9/28/2021