Neuromuscular

Focal Myositis

Morphology, General
Perimysium
Muscle fibers
Calcification


Focal Myositis: Muscle morphology


H&E stain
Focal myositis
  Perimysium: Wide; Cellular in some areas
  Endomysium: Hemorrhage
  Muscle fibers: Varied size; No necrosis

H&E stain

Focal Myositis: Perimysium


VvG stain
Perimysium: Wide; Abundant connective tissue

Gomori trichrome stain

H&E stain


H&E stain
Some areas of connective tissue are sworled or disrupted.

H&E stain
Perimysiym
  Some areas contain scattered large cells with large nuclei
  Diffuse staining of perimysium & endomysium with alkaline phosphatase

Alkaline phosphatase stain

Histiocytic cells: Scattered in perimysium & endomysium

Acid phosphatase stain


H&E stain

H&E stain
Lymphocytes: Occasional focal accumulations, perimysial or pervascular

Focal myositis: Muscle fibers


H&E stain
Muscle fibers
  Varied size
  Many 2C fibers
  No necrosis

ATPase pH 4.3 stain

NADH stain
Muscle fibers
  May be smaller at edges of fascicles
  Coarse internal architecture

NADH stain

Endomysial capillaries: May be large

H&E stain

Focal myositis: Calcification


H&E stain



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12/26/2014