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Alcohol (Ethanol) myotoxicity: Acute Myopathy

Muscle pathology   Necrosis     Early Distribution: Scattered fibers Cytoplasm: Pale   Muscle fiber properties     Alkaline Phosphatase     ATPase     PAS Also see   Necrosis: General features

Gomori Trichrome stain Necrotic Muscle Fibers: Early   Pale cytoplasm with small lipid droplets   Two fibers (Arrows) invaded by phagocytic histiocytes

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H&E stain

Necrotic Muscle Fibers
  Many
  Distribution: Scattered
  Pale staining: H&E, Gomori trichrome & NADH
    Contrast to: Dark H&E stain of fibers in rhabdomyolysis with Phosphorylase deficiency
  Dark staining of cytoplasm: C_5b-9

NADH stain

C5b-9 stain

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H&E stain

Necrotic Muscle Fibers
  Pale: Cytoplasm staining
    H&E
    Gomori trichrome
    NADH
    ATPase pH 4.3
  Dark: Cytoplasm staining
    C_5b9
Histiocytes
  Invasion of necrotic muscle fibers: Acid phosphatase
  Locations: Endomysial & Phagocytic (MHC-I stain)

Gomori Trichrome stain

Necrotic Muscle fibers: Pale staining on Gomori trichrome

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NADH stain

Necrotic Muscle Fibers: Cytoplasm
  Pale stained by NADH

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Acid phosphatase stain

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ATPase pH 4.3 stain

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Lipid droplets
  Small sizes
  Present in type I & II muscle fibers

Sudan Black stain

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C5b-9 stain

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MHC Class I
  Stains histiocytes scattered in endomysium & invading muscle fibers
  No upregulation by muscle fibers

MHC Class I stain

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Acute Alcohol Myopathy: Necrotic Muscle Fibers

H&E stain

Necrotic Muscle Fibers
  Pale: Cytoplasm staining
    H&E: Pale Cytoplasm & Myonuclei
    Gomori trichrome
    NADH
    ATPase pH 4.3
    Regional Δ
  Dark: Cytoplasm staining
    C_5b-9
  Cytoplasm: Other
    Lipid droplets: Small
    Misoriented myofibrils
    Disintegration
Histiocyte invasion
  Histiocyte invasion
  Invasion of necrotic muscle fibers: Acid phosphatase
  Locations: Endomysial & Phagocytic (MHC-I stain)

Gomori trichrome stain

NADH stain

Acid phosphatase stain

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Gomori trichrome stain

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H&E stain

Necrotic muscle fibers
  Regional cytoplasmic palor

H&E stain

Gomori trichrome stain

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NADH stain

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H&E stain

Necrotic Muscle Fibers: Early invasion by histiocytes

Gomori trichrome stain

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Necrotic muscle fibers: Invading histiocytes often stain for NADH

NADH stain

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Necrotic Muslce Fibers: Surrounded by Alkaline Phosphatase staining

Alkaline phosphatase stain

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Necrosis: Muscle fiber completely replaced by histiocytes

H&E stain

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11/6/2022