Neuromuscular

FHL1 myopathy: Emery-Dreifuss phenotype

Muscle
  Mild pathology
  Myopathy
FHL1: Reducing Body

H & E stain
H & E stain
Muscle fibers
  Small polygonal & angular: Scattered
  Very small, basophilic: Few

Gomori trichrome stain
Gomori trichrome stain
Muscle fibers
  Small polygonal & angular: Scattered
  Very small: Few

NADH stain
Muscle fibers
  Internal architecture: Coarse or irregular

NADH stain

NADH stain
Muscle fibers
  Internal architecture: Coarse or irregular

COX stain
COX stain
Muscle fibers
  Internal architecture: Irregular

Toluidine blue stain
Toluidine blue stain

Esterase stain
Esterase stain
Esterase stain
  Cytoplasm of Small muscle fibers: Dark
  Neuromuscular Junctions (Right): Small or Multisegmented

ATPase pH 9.4 stain
Type 2 muscle fibers: Mildly predominant

ATPase pH 9.4 stain
ATPase pH 4.3 stain

FHL1: Myopathy (C276Y heterozygous mutation)


H&E stain
Myopathy, Chronic & Severe
  Muscle Fibers
    Sizes: Varied
    Internal nuclei
  Connective tissue
    Endomysium: Markedly increased
    Perimysium: Marked fat replacement

Gomori trichrome stain

H&E stain
Muscle Fibers
  Myonuclei: Large; Irregular shapes
  Cytoplasmic aggregate (Arrow)

H&E stain
Muscle Fibers
  Vacuole: Irregular shape (Arrow)
  Ring fibers + Sarcoplasmic pads (Arrowhead)

H&E stain
Myonuclei
  Sizes: Mostly large
  Shapes: Irregular
  Number: Some fibers have increased numbers, scattered or clustered

H&E stain
Muscle Fibers
  Irregular cytoplasm structure (Arrow)
  Large nuclear clumps

H&E stain

H&E stain
Muscle Fibers
  Ring fibers + Sarcoplasmic pads

VvG stain

AMPDA stain

NADH stain
Muscle Fibers
  Scattered fibers are small & dark stained
  Internal architecture: Coarse

VvG stain

Esterase stain
Neuromuscular Junctions: Small or Multisegmented

Esterase stain

Esterase stain

Acid phosphatase stain
Histiocytes
  Scattered in endomysial connective tissue
  Intramuscular nerves: Myelin has increased staining

ATPase pH 4.3 stain
Muscle fibers
  Type 2 predominance
  Scattered Immature (type 2C) fibers

ATPase pH 9.4 stain

Phalloidin stain
Actin (Phalloidin) stain
  Actin in muscle fiber cytoplasm is often reduced & irregularly distributed.

Phalloidin stain

Laminin-α2 stain
Muscle fiber basal lamina
  Thick & Irregular around muscle fibers

Laminin-α2 stain

α-Dystroglycan stain
Muscle fiber basal lamina
  α-Dystroglycan is irregularly distributed on muscle fiber surfaces

MHC I stain
Muscle fibers
  MHC Class I: Mildly upregulated on muscle fiber surfaces

C5b-9 stain
C5b-9
  Stains endomysial capillaries

C5b-9 stain

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5/8/2023