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Cap Myopathy

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Cap Pathology: General

• Disorders of some of same molecules that produce Rod myopathies
• Pathologic features
• Histochemistry: Dark on Gomori trichrome
• May be selectively present one fiber type
• Location: Focal regions at periphery of muscle fibers
• Also stain for: Desmin; α-Actinin; Tropomyosin; Actin; SERCA2; Nebulin; Myotilin
• Ultrastructure
  • Abnormal Z-line material
  • Disorganized myofibrillar architecture

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Gomori trichrome stain

Caps: Dark regions (arrow) at the edge of muscle fibers
  Stain with Gomori trichrome, H&E, VvG & Desmin

VvG stain

H & E stain

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NADH stain

NADH stain

Caps
  No staining on ATPase pH 9.4 or NADH

ATPase pH 9.4 stain

ATPase pH 9.4 stain

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Caps: Desmin staining

Desmin Immunocytochemistry

Desmin: Present in caps

Desmin Immunocytochemistry

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Cap: Subsarcolemmal accumulation of filaments

From: R Schmidt

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Return to Cap myopathy

4/19/2021