LHN

Local Hypertrophic Neuropathy: Neurofibroma/Schwannoma Hybrid Nerve Sheath Tumors (N-S HNST)

Nerve
Structure
Organization
Axons
Neurofilament stain
Ultrastructure
Less involved
In OB structures
Vessels
Other

Onion bulb-like structures
Axons
Nuclear patterns
Patterns
Schwann cells
Ultrastructure

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

H&E stain

See: Control

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

See: Cell composition

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

See: Ultrastructure

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

See: Other Molecular Features

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

Onion Bulb-like 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

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

See: Molecular features

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
See: Control nerve

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
Loss of most non-myelinating Schwann cells
Small axons
Are present in layers of many onion bulb-like structures
In other areas have no associated NCAM stain
Axons: More loss of large than small axons

Neurofilament (Green)/NCAM (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
Loss of most non-myelinating (NCAM) Schwann cells
Small axons are presnt in layers of many onion bulb-like structures
Axons: More loss of small than large axons

Neurofilament(Green)/P0 (Red) stain

From: R Schmidt

Local Hypertrophic Neuropathy/N-S HNST: Central axons, Ultrastructure
Large axons have thin myelin for size

From: R Schmidt

Local Hypertrophic Neuropathy/N-S HNST: Central axons, Ultrastructure
Larger axon with no myelin has irregular structure

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
Small Axons: Present individually surrounded by Schwann cells (Below)

From: R Schmidt

Neurofilament(Green)/MBP (Red/Yellow) stain

Small, Unmyelinated Axons: Immature pattern
Small axons: Co-stain (Yellow) for neurofilament & Myelin basic protein (MBP) in absence of myelin
Large axons (Above): Have MBP (Red) in surrounding myelin