ACID MALTASE DEFICIENCY

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

Vacuoles are more common & larger in type I muscle fibers   Pale on ATPase pH 9.4 (Left) & Darker on NADH (Right)
ATPase pH 9.4 stain	NADH 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

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

PAS stain	Glycogen content May appear 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, Adult onset: Fusiform basilar aneurysm