Neuromuscular

NEMALINE RODS

General description
Infant
  Diffuse
  Type 1 small
  Ultrastructure
Child
Adult
Targets

Nemaline Rod Pathology

  • Light microscopy
    • Rods best visualized with Gomori trichrome stain
    • Dark blue structures
    • Most in muscle fiber cytoplasm
  • Contain
    • Z-line like material
    • α-actinin, actin & tropomyosin ± desmin at the periphery
  • Located in sarcoplasm: Often in regions with disrupted sarcomere structure
  • Occur in
  • Similar appearance & staining to: Cytoplasmic bodies
  • Also see: Rods or Cytoplasmic bodies in target fibers

Nemaline rod myopathy: Infantile

 
Gomori trichrome
Nemaline rods in gastrocnemius muscle from 4 month old child



No nemaline rods in quadriceps muscle from same child biopsied at 2 months of age

Nemaline rod myopathy, Infantile: Toluidine blue stains








Nemaline rod myopathy, Infantile: Other stains


H& E stain

Variable muscle fiber size
Refractile rods can be seen

ATPase stain, pH 9.4

Type I muscle fiber predominance


H& E stain

Rods: Actin stain


Phalloidin staining for actin
Focal (bright green), large and small aggregates of actin are present in some muscle fibers

Phalloidin staining for actin



Nemaline Rod Ultrastructure


Infantile-onset Rod myopathy

From: R Schmidt

 


From E Hardeman
Electron microscopy of rods from Z-lines in Met9Arg αTMslow mouse

Nemaline rod myopathy, infant (8 months of age): Type 1 muscle fiber smallness

Rods: More prominent in smaller muscle fibers

Gomori trichrome


ATPase pH 9.4
Type 1 muscle fibers: Small (Pale)

H&E
Muscle fiber sizes: Bimodal

NADH
Internal architecture of muscle fibers: Irregular

Nemaline rod myopathy, Childhood: 2 Different patients


Rods: In smaller muscle fibers

GT stain
 

ATPase stain, pH 9.4
Type I muscle fibers: Smaller than type II

Rods: In small & large muscle fibers

GT stain
Type I predominance

ATPase stain, pH 9.4
Fiber size variation: Bimodal distribution

H&E stain

Rods: In clusters in muscle fibers

Toluidine blue stain

Toluidine blue stain



Rods: Adult nemaline myopathy, 2 patients

Rods: Larger & Aggregated
 
Gomori trichrome

Rods: Small & Diffusely distributed in some muscle fibers
  Myopathic features: Varied muscle fiber size; Internal nuclei; Endomysial connective tissue increased

Gomori trichrome


H&E stain

Return to Rod myopathies

12/3/2014