Cytoplasmic Bodies

• Structure
  • Central region: Homogenous; Dark stain on Gomori trichrome similar to rods
  • Outer zone: Radially oriented filaments; May contain actin
• Location
  • Within cytoplasm: Central or subsarcolemmal
  • Early stage: May be associated with Z-Band
• Histochemical properties
  • Stain strongly with: Gomori trichrome; Myoadenylate deaminase
  • Stain poorly with: Myofibrillary ATPase & NADH
  • Type I fibers in distal type; Type I or II fibers in limb-girdle syndromes
    
  • PAS +
  • Molecular contents
    • General: Actin; Stain for Phalloidin
    • Other variable: Desmin, Dystrophin, β-Amyloid precursor, N-CAM
  • Differential diagnosis: Nemaline rods
• Ultrastructure: Variable
  • Foci of myofibrillary destruction: Z-disk derived bodies & streaming
  • Cytoplasmic or spheroid bodies: Thick & thin filament remnants
  • Aggregates of Z-disk filaments
• Disease associations
  • "Cytoplasmic bodies" described in
    • Cytoplasmic body myopathies
      • Properties: Larger; Less dark stained
    • Myofibrillar myopathies
    • OPMD
    • Plectin
    • Denervation: Associated with Targets
    • Immune & Inflammatory
      • IM-VAMP & Inclusion body myositis
      • HIV: Myopathy; IRIS
    • Myopathies, Other: Myotonic; Periodic paralysis; ? Dystrophies
  • Differential diagnosis
    • Rods: Also associated with abnormal Z-band structure
      • Rod properties: Similar color; Smaller; Many per muscle fiber; Often clustered