---

ACID MALTASE DEFICIENCY

Onset   Infant   Child   Adolescent   Adult Storage patterns   Ultrastructure Vascular

H&E stain

---

Adolescent Onset

---

H & E stain

Vacuolar Myopathy
Muscle fiber sizes: Varied
Vacuoles in muscle fibers
  Locations: Subsarcolemmal & Internal
  Contents: Clear or Pink-red staining material

Gomori trichrome stain

---

H & E stain

H & E stain

H & E stain

Muscle fibers with Vacuoles

• Vacuoles
  • Border: Sharp; No rim
  • Location: Cytoplasmic & Subsarcolemmal
  • Size: Variable: Small & Large, May occupy most of fiber area
  • Multiple in individual fibers
  • Most prominent in Type I muscle fibers
  • More prominent in some muscles, especially weak ones
  • Contents: Pale punctatew or wispy red material
• Muscle fibers: Other features
  • Necrosis: Rare fibers (Above; Arrow)
  • Size: Varied
  • Myonuclei: Large

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

Muscle fibers contain
  Clear vacuoles
  Small aggregates: Red (Below); Purple (Above right; Arrow)

Gomori trichrome stain

VvG stain

Acid Maltase deficiency
  Vacuoles & Aggregates in muscle fibers

VvG stain

---

Granules & Vacuoles: Acid phosphatase positive (Lysosomal)

Acid phosphatase stain

  Vacuoles: Some, but not all, have acid phosphatase positive material
  Acid phosphatase granules: May occur in muscle fibers without vacuoles (Below)

Acid phosphatase stain

LAMP2 stain

Acid Maltase deficiency
Lysosomal properties (LAMP2 stains) of punctate regions in muscle fibers

LAMP2 stain

---

Esterase+ aggregates in a few muscle fibers

Esterase stain

---

PAS stain

Glycogen storage (PAS stain)

• Diffuse, or patchy, increase in glycogen staining in muscle fiber cytoplasm
• Variably present in muscle fibers
• Vacuoles: Not clearly delineated; Many have no staining
• Aggregates: PAS+ (Arrow, Above)

PAS stain

PAS stain

---

Acid Maltase deficiency: Vacuoles & Fiber types

ATPase pH 9.4 stain

NADH 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; Above)
  Type 2 fiber sizes: Often larger than type I

ATPase pH 9.4 stain stain

---

Acid Maltase deficiency: Vacuoles & Fiber types

ATPase pH 4.3 stain

Fiber types
  Muscle fibers with vacuoles are often type 2C (Intermediate stained at pH 4.3)
  On ATPase pH 9.4 fibers with vacuoles appear to be type 1.
  Type 2C fibers are the most abundant fiber type.

ATPase pH 4.3 stain

---

Muscle fibers with vacuoles are moderately less dark than Type I fibers

ATPase pH 4.6 stain

---

Acid Maltase deficiency: Endomysial capillaries
  Increased numbers of endomysial capillaries stain at ATPase pH 4.3

ATPase pH 4.3 stain

---

Mid-Childhood Onset

Storage Contents in Muscle fibers: 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)
• Aggregates: Stain best for acid phosphatase

H & E stain

H & E stain

Storage Contents & Aggregates: Three patterns

• 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 storage (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 round 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

Storage material
  Pale-staining
  Metachromatic
  Aggregates

---

Vacuoles with Pale-stained, wispy material
  Vacuoles may be subsarcolemmal or internal
  Some vacuoles contain nuclei
  Multiple vacuoles in individual muscle fibers
  Vacuoles may partially or completely displace normal muscle fiber cytoplasm

H&E stain

H&E stain

H&E stain

Gomori trichrome stain

Gomori trichrome stain

VvG stain

---

Metachromatic, Granular Storage Material
  Magenta-colored granular material
  Probably later stage of pathology
  Often replaces most, or all, of muscle fiber cytoplasm

H&E stain

H&E stain

Storage material in muscle fibers
  Varied patterns of staining

Gomori trichrome stain

---

Gomori trichrome stain

Metachromatic, Granular Storage Material: Infant

Toluidine blue stain

---

Acid Maltase Deficiency: Aggregates

AMPDA stain

VvG stain

Acid phosphatase stain

Acid phosphatase stain

---

Acid Maltase Deficiency: Ultrastructure

From: Robert Schmidt

Cytoplasmic clusters of glycogen: Round shape
  Rare membrane-like material (Upper right)

---

From: Robert Schmidt

Cytoplasmic clusters of glycogen: Not membrane bound

From: Robert Schmidt

---

Cytoplasmic clusters of glycogen: Partially surrounded by membrane

From: Robert Schmidt

---

From: Robert Schmidt

Cytoplasmic Membrane-bound Aggregates

From: Robert Schmidt

---

Acid Maltase Deficiency: CNS Aneurysms

Acid maltase deficiency, Adult onset: Fusiform basilar aneurysm

---

Also see
  Acid maltase deficiency in childhood
  Phosphorylase deficiency

---

Return to Glycogen disorders
Return to Neuromuscular Home Page

8/25/2021