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Sporadic, Late Onset Nemaline Myopathy (SLONM)

Muscle features

• Muscle fiber size: Varied
• Myonuclei: Large; May be clumped
• Internal architecture
  • Irregular
  • Aggregates
  • Nemaline Rods
• Fiber types
  • Type I: Predominance
  • Type 2: Small; Many 2C

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SLONM: Myopathy
  Fiber size: Varied
  Endomysial connective tissue: Increased

H&E stain

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H&E stain

SLONM: Myonuclei
  Large
  May be clumped

H&E stain

Congo red stain

SLONM: Myonuclei
  Large
  Clumped in some fibers

Congo red stain

Gomori trichrome stain

SLONM: Myonuclei
  Large
  Some fibers: Clumped or Occupy entire myofiber cytoplasm

Gomori trichrome stain

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SLONM: Muscle Fiber Internal Architecture

VvG stain

Myofiber cytoplasm
  Irregular, Coarse Internal architecture
  Internal nuclei

VvG stain

VvG stain

Myofiber cytoplasm
  Irregular, Coarse Internal architecture
  Internal nuclei

NADH stain

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SLONM: Nemaline Rods

Gomori trichrome stain

Nemaline Rods
  Size: Very small
  Distribution in fiber: Diffuse; Often in large of cytoplasm
  May be more common in small fibers

Gomori trichrome stain

Gomori trichrome stain

Nemaline Rods
  Size: Very small
  Distribution in fiber: Diffuse; Often in large of cytoplasm
  May be more common in small fibers

Gomori trichrome stain

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SLONM: Clustered Rod-like Material

Gomori trichrome stain

Nemaline Rods
  Size: Very small
  Distribution in fiber: Diffuse; Often in large of cytoplasm
  May be more common in small fibers

Gomori trichrome stain

Gomori trichrome stain

Nemaline Rods
  Size: Very small
  Distribution in fiber: Diffuse; Often in large of cytoplasm
  May be more common in small fibers

Gomori trichrome stain

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SLONM: AMPDA aggregates

AMPDA stain

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SLONM: Fiber types
  Type I predominance
  Small fibers mostly 2C

ATPase pH 4.3 stain

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3/15/2024