AAA Syndrome
Denervation: Chronic Partial
 H&E stain |
Fiber Sizes: Varied
Large fibers: Hypertrophy
Small fibers: Angular, Elongated
Internal nuclei: Frequent
Partial fusion (Split): Common
Endomysial connective tissue
Mildly increased
Perimysium
Some replaced by fat
 H&E stain |
 H&E stain |
Fiber Sizes: Varied
Large fibers: Hypertrophy
Small fibers: Angular, Elongated
Internal nuclei: Frequent
Partial fusion (Split): Common
Endomysial connective tissue
Mildly increased
 H&E stain |
 Gomori trichrome stain |
Fiber Sizes: Varied
Large fibers: Hypertrophy
Small fibers: Angular, Elongated
Internal nuclei: Frequent
Partial fusion (Split): Common
Endomysial connective tissue
Mildly increased
 Congo red stain |
 Esterase stain |
Esterase stains small fibers darker
 ATPase pH 9.4 stain |
Large fibers: Mostly type 1
Small fibers: Mostly type 2
 ATPase pH 4.3 stain |
 H&E stain |
Split fibers
Internal nuclei
Myonuclei: Irregular shapes
 H&E stain |
 NADH stain |
Large fibers: Irregular internal architecture
Small fibers: Often dark stained by NADH
 NADH stain |
 NADH stain |
Large fibers: Irregular internal architecture; Split fibers
Small fibers: Often dark stained by NADH
 NADH stain |
Large fibers: Irregular internal architecture
 NADH stain |
 NADH stain |
 NADH stain |
Large fibers: Moth-eaten patterns
 NADH stain |
 NADH stain |
Partially-Fused/Split Muscle fibers
 VvG stain |
Partial fusion
 Gomori trichrome stain |
 Congo red stain |
Region of partial fusion often contains capillaries
Small fibers: Multiple myonuclei; Nearly pyknotic nuclear clumps
 Congo red stain |
 Congo red stain |
Partial fusion/Split
 Congo red stain |
 Congo red stain |
Partial fusion/Split
 NADH stain |
 NADH stain |
Partial fusion of 3 fibers
 Congo red stain |
Target fiber
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8/18/2024