Neuromuscular

FACIOSCAPULOHUMERAL (FSH) DYSTROPHY

FSH
  Adult
    Early
    Late
  Congenital

FSH: Adult

Capillaries
Inflammation
Muscle fibers
  Fiber types
  MHC-I
  Myopathy
  Necrosis
  Fiber pathology


H&E stain

H&E stain

H&E stain
Muscle fiber size: Varied; Atrophy & Hypertrophy
Regeneration: Basophilic muscle fibers
Endomysial connective tissue: Moderately increased
Inflammation: Around smaller, intermediate-sized vessels, not arteries or veins


VvG stain
Inflammation: Perivascular
  Location
    Around small perimysial vessels with no elastin in their wall (Above)
    Not usually around arteries or veins (Below)
  Cell types
    Mononuclear: Especially CD4 & CD8
    Large with large nuclei: ? Muscle regeneration

Congo red stain

Capillaries


VvG stain
Capillary pathology
  Multiple large endomysial capillaries

VvG stain

Necrotic muscle fibers
  Scattered
  Histiocytic cells slow to migrate away from necrotic fiber
  More common in muscles with less fibrosis

H&E stain
Necrosis: Early
  Pale muscle fiber cytoplasm

H&E stain
Necrosis
  Muscle fibers replaced by histiocytic cells

Acid phosphatase stain


Congo red stain
Necrotic muscle fiber
  Replaced by esterase-positive histiocytic cells

Esterase stain


ATPase, pH 4.3 stain
Small & large fibers are both types.
A few immature, type 2C, fibers are present.

(Intermediate staining; Arrow)

ATPase pH 9.4 stain, Patient 1
Large fibers: Types I & II.
Small fibers: Types I & II.

ATPase, pH 9.4 stain

FSH: Fiber pathology

H&E stain
FSH fibers: Basophilic muscle fibers with large, often clustered, nuclei

Gomori trichrome stain

H&E stain

Muscle fiber internal architecture
  Larger fibers: Whorled or Irregular
  Small fibers: Dark stained

NADH stain

MHC-1 is upregulated
  On the rim of all muscle fibers
  In the cytoplasm of smaller, immature fibers.

MHC-1 stain


Sudan black stain
Fat replaces perimysial connective tissue

FSH: Later stage

Myopathy
  Active
  Chronic
  Muscle fibers
Inflammation


H&E stain
Varied fiber size: Marked
Hypertrophic & Very small fibers

NADH stain
Hypertrophic fibers: Often have pale centers.
Small fibers: Dark & Pale stained

ATPase pH 9.4 stain, Patient 2
Large fibers: Types I & II.
Small fibers: Often type II.

Muscle fiber sizes: Marked variation
Endomysial connective tissue: Increased between muscle fibers
Inflammation: Foci surrounding smaller perimysial vessels

H&E stain

Varied muscle fiber size
  Small rounded muscle fibers
  Vary large, hypertrophied muscle fibers

VvG stain

Inflammation: Foci surrounding smaller perimysial vessels

H&E stain

Inflammation: Foci surrounding smaller perimysial vessels
Endomysial connective tissue: Increased betwen muscle fibers

Gomori trichrome stain

Inflammation: Perimysial focus

Congo red stain
Inflammatory foci: Mostly lymphocytes; Minority of cells stain for acid phosphatase & esterase

Esterase stain

VvG stain
Inflammation: Foci surrounding smaller perimysial vessels
Larger vessels: Normal

VvG stain

Intermediate-Sized vessels & Intramuscular Nerves: Normal in FSH

VvG stain


VvG stain
Active myopathy
  Necrotic muscle fibers
  Immature, regenerating muscle fibers: Darker stained, rounded, small muscle fibers
  Acid phosphatase positive cells scattered in endomysium

Acid phosphatase stain


Esterase stain
Necrotic muscle fibers: Replaced by histiocytic cells that stain for Acid phosphatase & Esterase

Acid phosphatase stain


NADH stain
Internal architecture
  Small muscle fibers: Varied staining, from normal to dark
  Hypertrophied muscle fibers: Often have clear central regions

NADH stain

Immature muscle fibers
  Small, rounded
  Cytoplasm: Stains for alkaline phosphatase

Alkaline phosphatase stain


ATPase pH 9.4 stain
Fiber types
  Large fibers: Types I & II
  Small fibers: More commonly type II

ATPase pH 4.3 stain

Congenital FSH


H&E stain
  Muscle fiber size: Varied
  Many small basophilic fibers
  Mononuclear inflammatory cells: Around smaller, intermediate sized perimysial vessel
Congenital FSH
H&E stain
Varied muscle fiber size.
Basophilic (immature) fibers.
No hypertrophy.
Endomysial inflammation.
Congenital FSH: ATPase
ATPase pH 9.4 stain
Smaller fibers are
  Type I & II

Gomori trichrome stain

Myopathlogy patterns

H&E stain
Fiber size
  Varied
  Small fibers: Rounded; Some basophilic
Nuclei: Irregular shapes; Large; One or several internal

H&E stain

Endomysial cell clusters

H&E stain

Small muscle fibers: Basophilic cytoplasm; Large nuclei

H&E stain

Internal architecture: Coarse; Immature

NADH stain


ATPase pH 4.3 stain
Immature muscle fibers
  Type 2C: Intermediate color on ATPase pH 4.3
  Alkaline phosphatase positive
  Scattered; Small

Alkaline phosphatase stain

Endomysial cells
  Histiocytic; Scattered
  Common pattern with MHC-I upregulatioon by muscle fibers

Esterase stain

MHC-1: Abnormal upregulation by muscle fibers

MHC-1 stain

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2/24/2016