Neuromuscular

ACID MALTASE DEFICIENCY

Infant onset
Childhood onset
Adult onset

Later Childhood Onset


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

H & E stain


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


H & E stain

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

LAMP2 lysosomal granules: Scattered in muscle fiber cytoplasm; Not in vacuoles

LAMP2 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