Neuromuscular

MYOTONIC DYSTROPHY

DM1: Chronic changes
DM1: Mild changes
DM2


Myotonic dystrophy (DM1): Chronic changes


H&E stain
  • Numerous internal nuclei: Often in longitudinal chains
  • Myopathic changes: Fiber size variation


Congo red stain
  • Numerous internal nuclei: Often in longitudinal chains


Gomori trichrome stain

NADH stain
Internal nuclei
Disordered internal architecture


Acid phosphatase stain

Acid phosphatase stain
Acid phosphatase positive granules in fibers



Myotonic dystrophy (DM1): Mild changes



Fiber size variation
Internal nuclei in some fibers
Smaller type I (darker) fibers
Disordered internal architecture



Myotonic dystrophy (DM2)


H & E stain

ATPase pH 9.4
Pyknotic nuclear clumps
Small fibers of both types
Internal nuclei (clear regions) most commonly
in type 2(dark) muscle fibers


NADH stain

Esterase
Pyknotic nuclear clumps stain darkly


From: Cory Toth MD
Pyknotic nuclear clump: Ultrastructure

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10/8/2008