Neuromuscular

MYOTONIC DYSTROPHY

DM1
DM2


Myotonic Dystrophy 1 (DM1)

Chronic
Late
Mild

Rossolimo "De la myotonie atrophique" 1902

DM1: Adult, Chronic changes

Muscle fibers
  Size: Variation
  Nuclei
    Internal
      Present in many muscle fibers
      Several in individual fibers
      Often clumped & in longitudinal chains
    Pyknotic clumps
  Acid phosphatase + granules
  Replacement by Fat

H&E stain
Perimysium: Connective tissue replaced by fat

H&E stain


Congo red stain

Congo red stain

H&E stain
Internal nuclei: Many; Irregular shapes; Often in longitudinal chains


H&E stain

H&E stain

Gomori trichrome stain

Internal nuclei
  Nuclei may be mildly large & clustered

Rossolimo "De la myotonie atrophique" 1902

Gomori trichrome stain

Internal architecture of muscle fibers: Disordered
  Aggregates
  Clear regions

NADH stain

NADH stain

Aggregates in muscle fiber cytoplasm

AMPDA stain
Fiber type abnormality: All fibers are type 1

ATPase pH 9.4 stain

Acid phosphatase positive granules in muscle fibers

Acid phosphatase stain

Acid phosphatase stain


H&E stain
Pyknotic nuclear clumps: May be large

Congo red stain


Myotonic dystrophy (DM1): Mild & Earlier changes


H&E stain
Internal nuclei
Pyknotic nuclear clumps


H&E stain

H&E stain

H&E stain
Fiber sizes:
Internal nuclei: In some fibers

NADH stain
Type I (darker) fibers: Smaller
Internal architecture: Disordered

NADH stain

Internal nuclei: In type 1 & 2 muscle fibers

ATPase pH 9.4 stain

Myotonic dystrophy (DM1): Late changes


H&E stain
Muscle fibers
  Size: Atrophy & Some hypertrophy
  Pyknotic nuclear clumps
  Nuclei: Large & Irregular shapes
Endomysial connective tissue: Moderately increased

Congo red stain

VvG stain


H&E stain
Pyknotic nuclear clumps
  Large
  May be present in connective tissue with few intact muscle fibers

H&E stain

Myotonic dystrophy, Type 2 (DM2)

Pathology
  Nuclei: Internal; More in type 2 fibers
  Pyknotic nuclear clumps
  Replacement of muscle by fat


H & E stain
Internal nuclei: Multiple in individual fibers

H & E stain

H & E stain

Congo red stain

H & E stain
Internal nuclei: Multiple in individual fibers

ATPase pH 9.4
Internal nuclei (clear regions)
Most commonly in type 2 (dark) muscle fibers

ATPase pH 9.4


Cytoplasmic granules:
  Acid Phosphatase positive



Acid Phosphatase

Acid Phosphatase

Pyknotic nuclear clumps


H & E stain
Pyknotic nuclear clumps: Large & small clusters of nuclei

H & E stain

Congo red stain
Pyknotic nuclear clumps: Large clusters of nuclei among larger muscle fibers

Congo red stain

H & E stain

NADH stain

Esterase
Pyknotic nuclear clumps: Dark-stained

NADH stain


From: Cory Toth MD
Pyknotic nuclear clump: Ultrastructure

Myotonic dystrophy, Type 2 (DM2): Late


Pyknotic nuclear clumps: Large
Muscle fibers: Largest are hypertrophied

Congo red stain

Pyknotic nuclear clumps: Nuclei stained for emerin

Emerin stain

Muscle fibers & Perimysium: Replaced by fat

Sudan Black stain

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6/2/2016