Neuromuscular

PERINEURIOMA

Child
Adult
  Muscle
Ultrastructure

Perineurioma: Adult



Gomori trichrome stain
Perineurioma: Tissue organization
Enlarged nerve with many, variably-sized, sub-fascicles
Many capillaries (Arrow)
Higher magnification (Right) shows many whorled pseudo-onion bulbs

H&E stain


Whorled pseudo-onion bulbs

Variable types of axons in whorls: Some whorls have multiple small axons (Left); Other whorls contain large axons (Right)

Neurofilament stain

Neurofilament stain

Differential fascicular involvement: More axons in some fascicles than others

Neurofilament stain
Some whorls contain myelinated axons

VvG stain

Perineurioma: Many endoneurial vessels

Alkaline phosphatase stain

Epithelial Membrane Antigen (EMA)
Perineurioma (Right): Staining of cells diffusely in endoneurium of enlarged nerve fascicle
Normal nerve (Below): Staining in perineurium, but not endoneurium

Perineurioma: EMA stains cells in whorls around axons

Perineurioma with axon loss: Collagen IV & Neurofilament stains

Neurofilament Green; Collagen IV red


Perineurioma: Chronic denervation & reinnervation of muscle


H&E stain
Grouped Atrophy & Fiber type grouping


NADH stain

Fiber type grouping: Large

ATPase pH 4.3 stain
Small angular fibers with targets

NADH stain

Perineurioma: Child



H&E stain
Perineurioma: Cellular endoneurium

H&E stain

Gomori trichrome stain
Perineurioma
  Endoneurium: Cellular; Loss of myelinated axons

VvG stain

Perineurioma: Many endoneurial vessels (Alkaline phosphatase positive)

Alkaline phosphatase stain

Perineurioma: Axon loss is varied among fascicles

Neurofilament stain

Perineurioma: ATPase positive small round structures

ATPase pH 4.3 stain

Perineurioma: Cells contain Epithelial Membrane Antigen (EMA)


Epithelial Membrane Antigen (EMA) (Green); Collagen IV (Red)
Perineurioma
  EMA staining
    Abnormally present in endoneurial regions of 2 large fascicles
    Lost, or reduced, in usual perineurial region
Small normal fascicle (Arrow at bottom): EMA only stains perineurium
Perineurioma
  EMA staining in endoneurial regions

Epithelial Membrane Antigen (EMA) (Green); Collagen IV (Red)

Control nerve
  Epithelial Membrane Antigen (EMA): Present in perineurium but not endoneurium (Green-Yellow)
  Collagen IV: Present in perineurium & endoneurium (Red-Yellow)

Epithelial Membrane Antigen (EMA) (Green); Collagen IV (Red)

Perineurioma: Endoneurial Cell Population


Perineurioma: Abnormal (Loss NCAM in) Non-myelinating Schwann cells
    Large axons (Green; Neurofilaments): Most are lost
    Small axons (Green; Neurofilaments): Many may remain within perineurioma
    Non-myelinating Schwann cells (Red; NCAM stain)
      No staining: Small axons appear "Naked"
      Present on ultrastructure

Neurofilaments (Green); NCAM (Red)

Control nerve
    Large axons (Green; Neurofilaments): Many are present; No associated NCAM stain
    Small axons (Yellow; Neurofilaments): Associated with non-myelinating Schwann cells (Yellow)
    Non-myelinating Schwann cells (Red & Yellow; NCAM stain): Associated with small axons, normally present in clusters

Neurofilaments (Green); NCAM (Red)

Perineurioma
  Loss of NCAM-positive Non-myelinating Schwann cells in endoneurium

NCAM stain

Control nerve

NCAM stain
Non-myelinating Schwann cells: Present in bundles all through the endoneurium

NCAM stain

Perineurioma
  Most large axons (Yellow) have associated myelin (P0 stain (Red)) surrounding them

Neurofilament (Green) & P0 (Red) stain

Perineurioma: Axons surrounded by regions of Perineurial tumor cells (EMA staining)


Neurofilament (Green) & EMA (Red) stain


From: R Schmidt

Perineurioma: Layered whorls of cells around unmyelinated or myelinated axons


From: R Schmidt


From: R Schmidt
Perineurioma: Layered relationship of neoplasm to other endoneurial cells
  Center: Axon, Myelinated or non-myelinated
  Around axon: Myelin with Schwann cell, or Schwann cell alone
  Surround: Collagen
  Periphery: Perineurial cell processes
    Interdigitated
    Basal lamina: Varied thickness

From: R Schmidt
Schwann cell around non-myelinated axon: Abnormal
  Surrounds only single axon
  Not stained by NCAM

From: R Schmidt

Perineurioma

  Pinocytic vesicles in cell processes (Dark Arrow)
  Fusion of regions of apposed membranes (Light Arrow)

From: R Schmidt

Return to Perineurioma
Return to Biopsy illustrations
Return to Neuromuscular Home Page
Return to Nerve biopsy

1/21/2017