Neuromuscular

ACID MALTASE DEFICIENCY

Infant onset
Childhood onset
Adult onset

Later Childhood Onset


H & E stain

H & E stain

H & E stain
Muscle fibers with vacuoles.
  • The vacuoles are
    • Clear and unrimmed
    • Located in cytoplasmic and subsarcolemmal areas
    • Variably sized: Small and multiple, or Occupy most of fiber area
    • Most prominent in Type I muscle fiber
    • More prominent in some muscles, especially weak ones.
  • Rare necrotic muscle fiber (Arrow; Above right)

H & E stain

H & E stain
Storage Contents: Two patterns
  • Clear material: In small or large vacuoles (Above), or
  • Metachromatic purple granular material: Often replacing much of muscle fiber cytoplasm (Below)

H & E stain

H & E stain


Gomori trichrome stain

Gomori trichrome stain
Storage Contents & Aggregates: Three patterns
  • Clear material: In small or large vacuoles (Above)
  • Purple granular material: Often replacing much of muscle fiber cytoplasm (Below)
  • Darker staining cytoplasmic aggregates (Bottom row; Left; Arrow)

Gomori trichrome stain

Gomori trichrome stain

Gomori trichrome stain

Plastic sections: Toluidine blue stain

Acid phosphatase positive granules in muscle fibers
  • Present in focal regions in fibers
  • No correlation with vacuoles or storage material

Acid phosphatase stain

Acid phosphatase stain

Glycogen storage (PAS stain)
  • Diffuse increase in glycogen staining
  • Variably present in most muscle fibers
  • Vacuoles are not clearly delineated

PAS stain

PAS stain

Glycogen storage, Variant pattern (PAS stain)
  • Glycogen staining of vacuoles and individual muscle fibers
  • Some increased staining is present in all muscle fibers

PAS stain

PAS stain

Vacuoles: More common & larger in type I-like muscle fibers
  Type I fibers: Pale on ATPase pH 9.4 (Left) & Darker on NADH (Right)

ATPase pH 9.4 stain

NADH stain

Fiber types
  Muscle fibers with vacuoles are often type 2C (Intermediate stained)

ATPase pH 4.3 stain

ACID MALTASE DEFICIENCY

Adult Onset



H&E stain


Gomori Trichrome stain
Storage Contents & Aggregates
  • Clear material
    • In muscle fibers with rounded vacuoles (Dark arrow)
  • Cytoplasmic aggregates
    • Stained by GT & VvG (Light arrows)


VvG stain


Acid Phosphatase stain
Lysosomal Granules
  • Location: Cytoplasmic
  • Size
  • Can occur in
    • Morphologically normal muscle fibers
    • Muscle fibers with cracks or GT or VvG positive aggregates
  • May be most sensitive histochemical feature of Acid maltase deficiency
  • Stains
    • Acid phosphatase stain: Left
    • LAMP-2 stain: Below

LAMP2 stain


ATPase pH 9.4 stain
Fiber types
  • Aggregates occur in both type 1 & type 2 muscle fibers


NADH stain
Internal architecture
  • Abnormally punctate
  • Small, irregular, internal clear regions


Patient

Normal Control
Glycogen content (PAS stains): May appear near normal


Caveolin-3 stain
Aggregate membranes
  • Nosology
  • Have features of sarcolemmal, surface membranes
    • May be continuous with surface membrane
  • Stain for
    • Membrane: Caveolin-3; Dystrophin
    • Contents: LAMP-2; Acid phosphatase

Caveolin-3 stain


Dystrophin (Dys-2) stain
Aggregate membranes
  • Nosology
  • Have features of sarcolemmal, surface membranes
    • May be continuous with surface membrane
  • Stain for
    • Membrane: Caveolin-3; Dystrophin
    • Contents: LAMP-2; Acid phosphatase


Dystrophin (Dys-2) stain


Desmin stain
Desmin
  • Increased in cytoplasm of some smaller muscle fibers
  • May accumulate around some AVSFs

Acid maltase deficiency, Adult onset: Fusiform basilar aneurysm


Also see: Acid maltase deficiency in childhood; Phosphorylase deficiency

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10/23/2013