Neuromuscular

MUSCLE FIBER NECROSIS

Images
  Necrosis
  Paraneoplastic
  BCIM

General features


Muscle Fiber Necrosis: Morphology


H & E Stain
Normal muscle fiber
Necrotic muscle fiber: Pale; Little phagocytosis
Necrotic muscle fiber: Phagocytosis by macrophages
Hypercontracted necrotic muscle fiber
Perimysium


H&E stain
Necrotic muscle fibers: Pale; Little phagocytosis (Arrows)

Gomori trichrome stain

H&E
Necrotic muscle fiber, Early
  • Fiber is pale & enlarged.
  • Internal nuclei may reflect
    invasion by macrophages.

NADH stain
Necrotic muscle fibers: Internal architecture has lost NADH staining (Arrow)


H&E stain
Necrotic muscle fibers: Phagocytosis (Arrows)

Gomori trichrome stain

Esterase stain
Necrotic muscle fiber, Late
Muscle fiber is invaded and
  replaced by phagocytes.

NADH stain
Phagocytic cells within pale necrotic muscle fibers: Mild NADH staining


Acid phosphatase stain
Necrosis: Stages
  Early: Pale stained muscle fibers
  Later: muscle fibers replaced by acid phosphatase + cells


Alkaline phosphatase stain
Necrosis: Alkaline phosphatase stains around the rim of muscle fibers


Toluidine blue stain

Necrotic muscle fiber (Longitudinal section)
  Pale
  Invaded by cells


Toluidine blue stain

Necrotic muscle fiber (Cross-section)
  Pale
  Invaded by cells

Toluidine blue stain

Necrotic muscle fiber
  Pale
  Invaded by cells


Toluidine blue stain

Cells in necrotic fiber

Toluidine blue stain

Non-necrotic, abnormal muscle fiber (Left): Dilated SR

Necrotic muscle fibers: Complement C5b-9 (MAC) deposition


Stain: C5b-9 components of complement (Membrane attack complex (MAC))

Necrosis: C5b-9 deposition diffusely within muscle fibers


Also see: Multi-Regional Paraneoplastic Myopathy


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11/1/2013