NMJs Normal Limb muscles Ultrastructure EOM Proteins Myasthenia gravis NMJs: Abnormal Congenital AChE deficiency AChR mutation Agrin mutations Immune Chronic, Undertreated Diagram Lymphorrhages Rippling muscles & Thymoma Pathological features Pathophysiology |
Esterase stain Congenital MG
AChR deficiency Small, pale NMJ |
Esterase stain |
Esterase stain |
Esterase stain |
Esterase stain |
Esterase stain |
H&E stain |
H&E stain |
H&E stain |
NEUROMUSCULAR JUNCTION ANATOMY: NORMAL & MYASTHENIA GRAVISFrom Drachman |
H&E stain |
Varied muscle fiber size: Atrophy & Hypertrophy Pyknotic nuclear clumps |
H&E stain |
Esterase stain |
Neuromuscular Junctions: Small, Irregular & Pale stained |
Esterase stain |
ATP pH 9.4 stain |
Fiber types Type 2 predominance Small are type 2 Large are type 1 (Above) or 2 (Below) |
ATP pH 9.4 stain |
Fiber types: Scattered type 2C fibers (Intermediate staining) are present |
ATP pH 4.3 stain |
H&E stain |
Muscle fibers: Occasional area with regenerating muscle fibers (Above) Normal muscle fibers: In most areas (Below) |
H&E stain |
Perimysial vessel: Associated inflammation extending into the endomysium |
H&E stain |
|
VvG stain |
Inflammation around intermediate-sized vessels Mostly mononuclear (probably with B-cells) Few cells stain for esterase (Below) Vessel endothelium: Stains for esterase |
Esterase stain |
Esterase stain |
Neuromuscular Junctions Size: Small or Elongated Intensity of staining: Normal |
Esterase stain |
Caveolin-3 Variably reduced or normal on muscle fiber surfaces |
Caveolin-3 stain |
MHC, Class I Abnormally upregulated on muscle fiber surfaces & cytoplasm in some regions |
MHC Class I stain |
H&E stain |
Muscle, Motor points (Areas with NMJs; Above = Top left & Bottom right near spindle) Endomysium: Mildly increased Muscle fibers: Enlarged nuclei (Below right) |
H&E stain |
Gomori trichrome stain |
Muscle, Motor points Endomysium: Mildly increased Muscle fibers: Coarse internal architecture (Above) Intramuscular nerves: Normal (Below) |
VvG stain |
Fiber types: Type 1 (pale) muscle fiber predominance |
ATP pH 9.4 stain |
Esterase stain |
Neuromuscular Junctions Very Pale stained (Above; Arrows) Some of the palest NMJs have neighboring acid phosphatase staining (Below; Arrows) |
Acid phosphatase stain |
VvG stain |
Gomori trichrome stain |
H&E stain |
Gomori trichrome stain |
NADH stain |
Esterase stain |
Esterase stain |
H&E stain |
H&E stain |
Gomori trichrome stain |
NADH stain |
ATPase pH 9.4 stain |
ATPase pH 9.4 stain |
ATPase pH 9.4 stain |
ATPase pH 4.3 stain Immature fibers (Intermediate stain; Type 2C): scattered in biopsy |
ATPase pH 4.6 stain |