Ring myopathy

Ring fibers (Ringbinden; Spiral Annulets) & Sarcomere disorientation

NADH stain

H&E stain

Congo red stain

Ring fibers

Stains
- NADH & AMPDA: Ring of striations, perpendicular to normal orientation, around circumference of muscle fiber
- H & E: Internal, ring-shaped, dark-staining regions; Often in smaller fibers
- Congo red: "Amorphous" ring in a muscle fiber with paler central region
Clinical correlations
- Poorly defined
- Associated disorders
  - Chronic myopathies
  - Myotonic dystrophy
  - Tenotomy
  - Muscle regeneration

NADH stain

AMPDA stain

NADH stain

Dark staining sarcoplasmic pad around rim of fiber (Right)

Ring Fiber
Circumferential sarcomeres around normally oriented sarcomeres
Sarcoplasm with abundant Mitochondria surrounds most of fiber
Lipofuscin granule (Top left)

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12/16/2021