ACID MALTASE DEFICIENCY

Onset   Infant   Child   Adolescent   Adult Storage patterns   Ultrastructure Vascular

H&E stain

Adolescent Onset

H & E stain

• 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 (Below; Arrow)

H & E stain

H & E stain

H & E stain

H & E stain Clear vacuoles   Size: Small or Large   Location: Subsarcolemmal or Central   Number: Multiple in individual muscle fibers   May contain myonuclei   May be marked variation in muscle fiber involvement (Below): Some severe, Others none

H & E stain

H & E stain

Gomori trichrome stain

Gomori trichrome stain

Gomori trichrome stain

Gomori trichrome stain

Acid phosphatase stain

Acid phosphatase stain

• Diffuse, or patchy, increase in glycogen staining in muscle fiber cytoplasm
• Variably present in muscle fibers
• Vacuoles are not clearly delineated

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

Mid-Childhood Onset

• 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)
• Aggregates: Stain best for acid phosphatase

H & E stain

H & E stain

• Clear vacuoles: Small or Large
• 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

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

PAS stain

PAS stain

• Glycogen staining of vacuoles and cytoplasm in individual muscle fibers
• Some increased cytoplasm staining is present in many muscle fibers
• Cytoplasmic staining can be variable within fibers

PAS 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 Large: May have features of   Autophagic vacuoles with sarcolemmal features (AVSF) Small: Multiple punctate regions 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 Autophagic vacuoles with sarcolemmal features (AVSF) 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 Autophagic vacuoles with sarcolemmal features (AVSF) 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: Myofiber Storage Patterns

H&E stain

H&E stain

H&E stain

Gomori trichrome stain

Gomori trichrome stain

VvG stain

From: Robert Schmidt

H&E stain

H&E stain

Gomori trichrome stain

Gomori trichrome stain

Toluidine blue stain

AMPDA stain

VvG stain

Acid phosphatase stain

Acid phosphatase stain

From: Robert Schmidt

From: Robert Schmidt

From: Robert Schmidt

From: Robert Schmidt

From: Robert Schmidt

Acid Maltase Deficiency: CNS Aneurysms

Acid maltase deficiency, Adult onset: Fusiform basilar aneurysm