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Myopathy with deficient Chondroitin Sulfate C in Connective tissue

Myopathy   Myonuclei Δ   Atrophy Inflammation Perimysium   Histiocytes   Alkaline phosphatase Chrondroitin SO4 C

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H&E stain

H&E stain

Muscle fiber morphology

• Fiber size: Varied
• No active myopathic changes
• Myonuclei: Irregular shapes

H&E stain

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H&E stain

Muscle fibers
  Myonuclei with irregular shapes
  Varied fiber size

H&E stain

Congo red stain

Muscle fibers: Myonuclei with irregular shapes

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Gomori trichrome stain

Muscle fibers: Varied size

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H&E stain

Perifascicular muscle fiber atrophy

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Type 2 muscle fibers: Very small
Type 1 muscle fibers: Mild atrophy; Varied size

ATPase pH 9.4 stain

ATPase pH 9.4 stain

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Congo red stain

Inflamatory pathology
  Cells near & around Perimysial vessel

Congo red stain

H&E stain

H&E stain

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Acid phosphatase stain

Perimysium
  Acid phosphatase positive histiocytic cells

Acid phosphatase stain

Alkaline phosphatase stain

Alkaline phosphatase stain

Perimysium
  Increased staining by alkaline phosphatase

Alkaline phosphatase stain

Connective tissue changes

• Perimysial cells staining with acid phosphatase
• Perimysium staining with alkaline phosphatase

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Chondroitin sulfate C: Patterns of Staining

Chondroitin sulfate C stain

Normal control
  Dark staining on endomysum & capillaries (Arrow)

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Chondroitin sulfate C stain

Myopathy
  Reduced staining on endomysum & capillaries

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Chondroitin sulfate C stain

Myopathy
  Reduced staining on endomysum & capillaries; Increased staining in muscle fiber cytoplasm

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Chondroitin sulfate C stain Patient muscle: Pre-Rx

Chondroitin sulfate C stain Patient: Post steroid Rx

Chondroitin sulfate staining in muscle endomysium

• Normal: Abundant on skeletal muscle endomysium & endomysial capillaries
• Myopathy: Absent in patient muscle before treatment
• After corticosteroid treatment: Returns to near normal

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1/28/2019